@@TheGT350Garage - Looking past the obvious, I would at least like to know what tool to pick up and what to adjust, and for what outcome I am looking for. I have an idea what I am looking for, but I came here to see if you had something special to tell me, that I dont know. Since you didnt mention anything about what tools to use, what to adjust and or tips n tricks, cant say I know anything NOW I dont already know. Was all that, just to say "set your a/f to 14:1 on non ethanol gas and pull back timing? If so, I will give you 10 minutes of credit while still demanding my 40 minutes of life back!
A very informative video. Kinda made me look at things a little different. It does make sense considering that how you tune a forced induction type engine i would imagine. I have been trying to figure out how to do this. I tried fiddling with the dynamic cr calculators. But they are all over the place. Would you have any examples in videos or upcoming videos? I have an 11:1 cr aluminum headed 383 chevy. And I have been trying to figure out if I could run a 224/224 110 icl/ 114lsa cam. And if I could install it on a 106icl. Running 91-93 pump gas.
@JoshF89 I do have a video in the works that will really help you. As for your cam selection at your compression ratio, it’s quite small and will make far more cylinder pressure than you want. Duration will need to be 12-18° more than you have and the ICL/LSA numbers I use on high compression builds for street use are drastically different than what you’re describing. If you’d like to discuss cam selection further, please shoot me an email to thegt350garage@gmail.com and we can go from there.
Great video, and some tuning tech genius that I suggest every enthusiast takes a moment to archive! I was running a poncho on evil "pump gas" with a 13:1 compression 400 Tri-power in a 4200lb car back in the early 90's. A few interesting projects since then as well. Everything you discussed is spot on with the tuning conditions utilized in my Pontiac builds. The one topic you didn't touch on, but was anticipating, was your knowledge of how spark plug design, voltages, and heat range selections tie into (affect) the flame propagation cycle, timing, and mitigating pre-ignition.
My take on plugs is different from most. I’m not a fan of big gaps, .025-.035” depending on the engine and ignition system being used. I like Autolite Copper and Autolite Racing plugs for most engines, which inevitably leads to an argument from someone who thinks NGK TR6 Iridium’s are gods gift to engines. I’m not a fan of “gimmick” plugs, it doesn’t need multiple ground straps, V shapes, Y shapes, U shapes, or any special metals. I don’t run platinum or iridium plugs because of heat range issues and inconsistencies I’ve had with them. And I’m not a fan of fine-wire center electrodes, I’ve seen many go “missing”. Also, plugs are cheap, and relatively easy to service, if you want longevity from spark plugs, keep the car stock. Heat range only needs to be hot enough to keep the plug from fowling at idle, gap needs to deliver a spark that’s strong and consistent. This is an area where people tend to overthink things and end up spending money they don’t need to. Copper plugs will typically last 10-15k in a reasonably maintained street application, and they should be checked every oil change or seasonally. Coppers are also cheap enough to keep a set stashed in the car if it’s a driver and can be changed on the road if you have an issue.
@mikemaguire5507 if you don’t take the time to understand the difference between modern fuel and fuel of the past, you’re probably not going to get the results you want.
Great video, I agree. I ran a 11:1 289 with a 650 dblpumper & 32/34 deg.on any premium pump fuel for years in the mid 70s. Never had a problem. Had to use 2:79 gear once(built a 9"w/Detroit Locker 4:10) and got 28 mph hyw.
You could only run 28 mph on the highway? Damn, should have geared it differently, that's slow as f***!! My car would whip dat ass! Talk about getting gapped!! ROFLMFAO!!
I've been building engines for street and strip since 1970. Yes, I'm old. 71. I agree with what you're saying. I still have a small hot rod shop in Texas and am still playing with cars. My daily driver is a 1962 Falcon , powered by a modified 302 .12.5 compression, 351 Edelbrock heads, Offenhuser Tunnel Ram with Holley 550cfm Tunnel Ram carburetors. Top loader 3 55 posi. 9 inch . 2400 lbs car. Iv been running 92 oct for the years iv been driving it. Timing full advanced at 28 degrees. When I'm racing it I use 110 oct. advance timing through my MSD Ignition. Anyway I just run across your channel. Thanks enjoyed the presentation.
You have a fun setup, it’s likely you’re running a decently large camshaft. The point of the video is to help people understand what’s possible, it’s rare to find someone like you who will admit to doing it successfully.
One of the most fascinating things that impress me in the modern internal combustion world is the 5.3 liter V8 with cylinder deactivation in my 2015 GMC Sierra 1500 pickup. It delivers 355 net hp on an 11 to 1 compression ratio on 87 octane gas! It makes great power and I can hypermile in it by running a reduced fuel load (weight) a lightweight tonneau cover for the bed (reduced turbulent drag) and higher tire pressures (35 psi cold). On cruise control on the rolling highway at 55 mph I have repeatedly achieved 30 plus mpg with an all-time high of 32. I'm not flying along like everybody else at 80mph, but the point is that you can achieve great mpg on a 5,000 half ton pickup if you want to. I can imagine even better results on flat terrain.
Without the benefit of a knock sensor to detect the threshold of too much spark advance, it’s a bit risky to run 87 octane above about 10.5:1 compression. But with a knock sensor, I’ve run 87 octane win fuel injected engines as high as 13:1 with good results.
.....You my friend are blessed with a high intellect.................far above average hot rodders..................................I'm 71........Been around studies of engine building and Drag Racing since 1965..........I'll have to watch this video a few times and record on paper what I may forget......Thanks.......
@Fordcertian if you tune to the fuel, you don’t need to change the fuel. Octane boosters are inconsistent and essentially a bandaid fix for incorrect ignition timing. They do nothing to improve the energy content of the fuel or the conversion of the energy in the fuel.
Brother, you are a Godsend!!!.....I have had many sleepless nights of the last few days contemplating how to set up my new 496 Chrysler...at 3400 ft in Hesperia California my calculation shows I need at least 10.6 static compression BUT I like to go down the hill to Riverside to see friends where it's 500 to 800 ft...yes, I have issues, but after this, I'm more confident I can make this work with a little attention!
I’m originally from SoCal and lived there until 2017. If you run a vacuum secondary carburetor it senses demand and opens less at higher elevations. You basically just tune the carb as if the tune was for “elevation” on the primary side, and at 3500ft you’ll want an AF ratio of 12.7-12.9:1 at WOT and 13.3-13.5 at cruise. Easy to do with a Holley 4150 Vacuum Secondary, you’d just need the big 870cfm model. For the lower elevation tuning, you’ll leave the primary side of the carb alone and increase the jet size 4-6 numbers so that your AF ratio is about 12.2-12.5 at WOT and so you cruise in the 13.0-13.2 range down in the IE. The numbers sound rich, but the fuel in CA is heavily oxygenated and burns like a leaner mixture with its lower stoichiometric air-fuel ratio of 14.0:1-14.1:1. I used to live in the AV and I’ve run cars at LACR, Famoso, and Irwindale, all using the same tune, and driven them at 4000+ft elevation over the Crest, the Grapevine or Tehachapi to get to the track. If you’re still building the engine, the big Mopars like compression, I wouldn’t hesitate to go 11-11.5:1, then run a bit more cam and let the cam specs help you arrive at a dynamic compression in the 9.0-9.5:1 range. If you use the information I provided about timing, and I’m doing a follow up video to give even more insight into building the timing curve, you’ll be able to dial it in so you don’t have drivability or temperature issues.
@@TheGT350Garage thanks for the reply, it means alot to me right now, I am currently reconfiguring this engine, and yes, it appears that 9.0 to 9.5 is what seems right...but the common "thought" is saying I need to be at 8.5 to be "safe"....I actually have flat tops in it now that are .025 down in the hole..I'm showing 11.3 static, but they are sitting. 025 in the hole right now.. I was thinking about getting new pistons with a 12cc dish to put me at 10.6 or a true 11.1 if I take a bit more off the deck..I think with the quench issue, this would be best.(but I'd be interested in your opinion) I'm using the Trickflow heads with a 78cc chamber so I think this setup would be good.ive see 3 builds with these heads, and 32 to 34 degrees totalis what they seem to like best, this falls in line with your timing strategy from what I can decern..I'll probably go with a 250 @ 50 cam like you suggest...I already have a Ultra 850 HP carb, which may be a bit counter productive, but I will probably stick with it seenings that my car is a 4 speed....I'll be looking forward to your next video!
The “conventional thinking” of the past 50 years still holds a lot of guys back, and combined with a very poor understanding of modern fuel, it has lead to many an argument surrounding the operation of high compression engines on pump fuels. On my 289 Ford, the static compression is going to be 12.0:1. The intake valve closes at 70°ABDC and that comes in at 9.09:1 Dynamic compression. In reality it’s higher than that due to cylinder filling characteristics and other factors, much as I describe in the video. If you want to provide more cam info we can discuss the details specific to your engine. I will say a flat top with quench is better than a generic dish at “zero deck”. If you really wanted to fine tune the combination for a specific compression ratio, you’d want the piston at zero deck and an inverted dome (a dish that mirrors the shape of the combustion chamber to limit quench and control the charge better. Your 850 HP Ultra carb is A LOT of carburetor for street use. Not the CFM rating, that’s fine, it’s the extremely adjustable nature of those carbs that get a lot of guys in trouble. You will need to study what all of the various adjustments are doing and carefully adjust accordingly. It’s going to take some effort to truly understand how capable that carb is and make it work for your needs. I would also suggest splitting the difference from an altitude perspective and tune to the middle, meaning if you live at 3400ft and you’ll occasionally get down to 600ft, tune the car to operate best in the 2000-4000ft area and don’t beat on it at lower elevations with higher air pressure and density without verifying your AF ratio. (Investing in a wideband AF Ratio sensor kit is prudent, and about a $400 expense these days for a dual sensor kit.)
@@TheGT350Garage well, I have a hand full of cams on hand, and I'm ready to pull the trigger tomorrow on pistons if needs be. This is a "back up" engine for my 528 Hemi that I will pass on to my son eventually. I don't want to make it too complex for him, but I don't want a "girley-man" engine either...looking for a maximum effort pump gas engine. I've got a 243 @ 50, with a closing on intake at 46 This is a trickflow hydraulic roller that is pretty popular, and I've got a solid flat tappet with a 260 @ 50 duration with a closing at 54...I think this is a bit outside of where I want to be, but I've seen it done before in Diamond bar with a similar engine I built 20 yrs ago with the same problem (I gave up on it because it rattled on pump and I was outta $$$ and sanity)...I've got new tappets and pushrods for either setup, and I could see going either way..but for simplicity probably stay hydraulic roller. Yes, the HP carb is a bit complicated, but that is what attracted me to it. I've had Fuel curve West fully prep it, so it should be a barrel of monkeys at some point.
Depending on how you calculate dynamic compression, by using duration at 0.050” vs 0.006” you get very different numbers. Going back to my combination at 12:1, using the .006” duration gives 9.1:1, but using the 0.050” duration value gives 10.7:1. Your cam spec is at 0.050”, with 11:1 would give 9.9:1, but using the 0.006” advertised duration it’s 8.3:1. Between .050” and .006” the valve is closing with the piston rising and you will have reversed flow out of the port against the air mass stacking on the back side of the intake valve, so it’s going to be something in between those numbers. You should be fine running around 11:1 with that cam. If you want to fine tune it, you can advance or retard the cam 6-8 degrees from where it’s ground to get the desired result you want.
Great video. It has definitely shot my fuel / octane theories all to hell. I found it extremely informative. Thank you Professor I will have to study much harder.
If you had a fairly decent cam in the engine that makes complete sense. It also depends on temperature, elevation, and some other factors. One of my favorite 302/5.0L Ford combinations 20+ years ago was a champion of 87 octane at 9:1 compression. It made 345hp to the wheels, about 415hp at the flywheel, year round in n 87. There was no gain from increasing the octane, it made slightly less power on 91. Back then I was obviously much younger and the guys I was working with were very stuck in the mindset that the fuel of the day was grossly inferior because they had experienced the Muscle Car era and I couldn’t possibly have any idea of what I was doing.
Walter, I just found your channel today and I subscribed right after watching your video on Performance Re-Curve. I have some distributor re-curving I was planning on doing this Spring and I learned a lot from you. Thanks for sharing!
Lots of good info. I will have to watch this multiple times to actually soak it up. Really makes me question if I really can drive my 400 SBC at 12.5:1 on pump fuel with iron heads. With the way you describe thing it really makes me question what I thought I knew but has me wanting to confirm it’s wrong too. U got a new follower that will be sharing your content. Thanks and look forward to learning, understanding more
Second gen camaro. 409 c.i. SBC. 4 speed versus TH400. What compression should i use? No pwr steering. No pwr brakes. ALthough has AC. The engine planned is a sleeper stock look engine having a 4.035" bore X 4" stroke. Custom mahLe pistons. Ported and worked Iron eagle heads. Hydraulic Roller Retro 288* cam with 106* LSA 70* IVC. And the safety margin during chassis dyno or versus stand dyno only.
This isn’t a straightforward question. The transmission doesn’t determine the compression ratio. There is a lot of missing information, like is that the duration at .050” or the advertised duration (I suspect advertised). The @.050” number is a better gauge of cam size. If the @.050” numbers are in the 225-235° range, compression should be roughly 10-11:1, 235-245° 11-12:1. The 106° LSA is pretty tight and will work fine with higher compression, but there are a lot of factors that go into cam selection, and ultimately cam installation. The manual transmission won’t care what the combination is, just use a good clutch and gear the rear axle appropriately. A TH400 however will need a converter that matches the engine’s output characteristics if you want it to be successful. I’m not sure what you are looking for in the way of a safety margin for dyno testing. Be thorough and maximize the average power. Testing isn’t cheap so have a plan, stick to it. Start with 26-28° of ignition timing, get the air fuel ratio dialed in at about .83-.85 Lambda (slightly rich) maximize your ignition timing to find the highest average and peak horsepower and torque. Then fine tune the air fuel ratio into the .86-.88 Lambda range for the hero numbers. On the street I would pull out 2° of timing and jet up 1-2 jet sizes on all four corners of the carb.
You are a good teacher, you have a great demeanor for teaching. Im a car guy DIY'er and an Engine Parameter Numbers Cruncher. I started back in the early 80's myself doing my own wrenching and noticed back then the wall of nonsence you go thru in the engine building world way back then. Anytime I run into one of "those" ppl who grew up on [all that misinformation] on hot rodding an engine; I always ask one question. That question addresses "Size". When someone uses vague or ambiguous language as Big and Lots of Hp or Lots of Tq - they get asked the question; How do you qualify small, medium, large engine parameters relative to mild, moderate, maximum engine output? Most hot rodding bench racers look at me with blank eyes and give me the shoulder shrug I Dont Know answer. If they respond by asking me to tell them more, then I know I have someone who is teachable. If they respond by arguing their brain washed nonsense, I'll give them a few more questions that will/should allow them to break through the brain washing. If they dont come around - they arent teachable; I dont waste my time I just walk away! Ive even asked my questions to some of the big guys - and dont get an answer. Its interesting how some very knowledgable engine builders have egos that wont allow them to say, "I dont know, tell me more". Your content is just the tip of the Iceberg, but theres only so long you can make your video before it turns into a college semester class room on engine theory. Thx for taking the time, enjoyed the vid Edit: You actually addresed Dynamic Compression. Most content on Dynamic Pressure is based on the 50's thru 70's tech. If ppl wanna understand Dynamic Compression they should look up The Slider Crank Mechanism and how to chart that data thru 180° of travel (piston travel). It will help them see how much volume remains in the cylinder at each degree of crank rotation. Having watched all of this video now, which I consider Part 1, you should make a Part 2 that moves beyond the basics. Part 2 should focus on Energy Content of the Fuel relative to High Static Compression and Lamda. I just found your Part 2 on this subject; gonna watch that vid now
Thanks! I’ve had a rough year for making content, I hope to be back at it soon, but Part 3 addressing my stance on dynamic compression ratios is about ready to present and Part 4 isn’t far behind. I’ve compiled most of the work I’m presenting in the videos and may self publish it, or lean on some industry friends for a favor to get hooked up with a publisher. It’s always hard to get acceptance whenever you’re presenting ideas that aren’t popular or change longstanding opinions. Great feedback.
@@TheGT350Garage I wasnt going to say anything until you mentioned trying to publish your knowledge to others. Back in the late 90's early 2000's I went thru an adventure on trying to understand the engine. The internet back then wasnt as helpful as it is now. In my few years of research I ended up purchasing 70 books. Back then I wasnt planning on writing a book, I simply wanted to understand the engine. In my early research I decided to put my notes in book form name it, "Dynamic Compression: Never Overcam Your Engine Again". Upon further research I changed the name to, "Understanding The Performance Engine Equation". I held off selling the book as I hadnt any process for the reader on how to properly custom match a Cylinder Head to the Block's Cylinder when upgrading performance: or how to qualify performance in general. I didnt want my book to be incomplete like everone else's book; full of pic's but no useable content. I had to figured out how the relationship changes between the Cylinder Head and Cylinder with each incremental upgrade in Engine Output? A year later, I finally understood. Life took me in another direction so I never really publicized my book, other than being on multiple bulletin boards. A guy in Brazil who owned a Custom Intercooler shop wanted my book. I sold him a copy even tho I was still in the editing process; he adamantly wanted it - guess that makes me an International Author; woo'hoo. He later sent me an email stating he never would've understood why the engine behaves the way it does without understanding dynamic compression. Engine math is Terciary, not one dimensional. Once you know what I call the three overriding parameters, you can Transpose your equations and know ALL parameters of someone else's engine. Ive said all this so you know, I know what your going thru.., I feel your pain. In our passion to work on, build cars, enjoy their performance, and teach others, you will always run into the disinformation crowd. I call them the never wanna say Volume Cult. I call them the Volume Colt as they've bought into only knowing a Cylinder Head's Intake Port's Pinch Point Area Sq.In. and never address how that Pinch Point Sq.In. is relative mathmatically to a specific Intake Port Volume. They are of the Volume Cult mind; remember tho, they are your target market. You'll go thru 100 heavily brainwashed ppl before you find that one person that says they wanna know more. We wanna teach and pass on our knowledge because of that one person that wants to know more, so be patient - which you are. You can always get published by someone. However, with the internet - self publishing is always an option. Create your own website and automate the sale of your book, digitally. My book in paper form was over 600 pages. Once you have your book in Ebook format, your talking kilobytes. Bandwidth is much cheaper now days than it was in the late 90's. If you go the self publishing route keep in mind if you go cheap on the Bandwidth your website will buffer on your customer's end. Dont know if you are knowlegeable on how Bandwidth providers divi up the Tower wherein their websites are stored. If choose minimum bandwidth, your website is shared on a Blade within the Tower until that Blade is full. If you choose unlimited bandwidth, you get your own Blade, your customers are happy as there is no buffering. The problem I didnt like about trying to sell my Ebook was how easy it is to Page Copy from the Internet. Can you actually stop ppl from buying or copying your book, repurposing your book as their own, and what are you willing to do when someone violates your copywrite. Another question that I realized was how many copies would I have to sell to make my efforts profitable? Bandwidth costs from the late 90's was the hurdle I couldnt get over, maybe you will have better luck as bandwidth is cheaper now days. Anyway, hope I was able to throw some things at you to think about.
@kevinshasteen5682 I’m not to the point of being able to publish my work yet, too much to do, minimal time because my day job is teaching young automotive technicians engine operation, diagnostic practices, emissions technology and preparing them for ASE A1, A8 & L1, L3, L4, & G1. My student have passed over 65 ASE certification tests so far this year after completing my classes. I’m very proud of my students who push themselves to achieve their goals and get hired into the industry with guaranteed wages as apprentice technicians instead of being stuck in a lube pit somewhere. I actually don’t like using “dynamic compression” at all. It doesn’t work, the science, physics and thermodynamics involved easily disprove its value. Modern automotive engineering has adopted “effective compression” as a result of the simulated Atkinson cycle and this is a scientifically accurate approach that addresses real conditions. You’ll like the next video. And on the topic of hosting on the Internet, bandwidth is a concern, copyright infringement is a major concern, and how to disseminate the content is not straightforward at all. I know several magazine editors and automotive authors who have published books and articles over the past 30+ years and I’ll probably try to work with one of them to make a book happen with a known publisher when the time is right. There are a few of them who I might convince to lend their blessing to the book. Time will tell.
You are a teacher, explains why your so good at it; your students passing their tests are indicative that you are an effective teacher! Dynamic Compression is only ineffective if you use 1950's parameters. Dont dismis the process simply because the #'s are outdated. Update the #'s so your equation for the process will be updated. The numbers can blur the lines the more efficient your engine becomes. Fuel Injection can be very efficient, more efficient than carbs - some will argue otherwise. So junk #'s in equals junk #'s out which is why I changed my books title: it was incomplete on its own. Ppl's minds will open when they undetstand Dynamic Compression - so, its still a good teaching tool. Looking forward to your next video.
@kevinshasteen5682 I suspect your numbers probably lean hard on what is now termed Effective Compression to be able to get things right. I think you’ll find the next video a satisfying watch, and I’d be happy to compare more detailed notes via email after you’ve had a chance to see where I’m coming from with it.
Excellent! Great research and presentation. I’m working on a 1970 boss 302 that has suffered detonation and it forced the porcelain section of the plugs right out of the steel portion of the spark plugs. The engine uses a @13:1 piston. I’m pulling the heads on 11/25/23 I’ll see what damage occurred. Thanks again.👍
A 13:1 Boss 302 is a wicked combination, check the piston to deck clearance (should be zero) you want to really tighten up the quench area to about .040” (just the thickness of the gasket, no more. The closed chamber Boss/Cleveland heads do benefit from more cam duration and carefully chosen cam timing events to get the best out of them. In 11:1 or higher Cleveland and Boss 302 engines using iron heads, I install Autolite Racing AR25 spark plugs because they are a cold plug and produce good results. The AR25 is a much colder plug than an Autolite 23 (Autolite 25 is stock) or NGK UR5, I avoid platinum and iridium in these older engines, because they are designed to run hotter and self clean in modern engines with knock sensors and the computer can sense and catch the early signs of detonation that can wreak havoc on our older engines. I also run tighter gaps with high compression to improve the intensity of the spark, typically in the .028-.032” range with compression over 12:1 or when running boost (artificial high compression). Basically if your ignition system is up to the task, the cold plugs will work perfectly, you need a quality spark, but don’t want the spark plug acting as a glow plug. As for timing, the chambers are a good design, but I’m assuming you have a dome to get the compression that high and that really kills combustion efficiency. I shoot for the smallest chamber and flattest piston possible in small displacement engines, in big displacement combinations like a 408 Clevor, I use the small chamber and order a custom inverted dome piston where the dome mirrors the chamber and still nets that critical .040” quench area. You may find that you can give up a little compression and gain some power by improving the efficiency of the chamber.
@@TheGT350Garage thanks for all the info, it gives me much to think about. Yes I’m using Autolite25’s, car ran strong until my son let the fuel get stale during winter and then took it out on the back roads to warm it up. I suspect that the head gaskets are blown, yes it was zero decked. I’m using ARP head studs, also cam lift on paper was 0.540 but with the .030 clearance, if I go any tighter I run into coil bind. So maybe I should address all of this during this head removal. I dont have the cam card handy. Thank you for answering me. You can see my car on my channel called Laut Burns!
I'm currently building a .030" over Ford 302 with domed SRP pistons. With 60cc chamber heads it should fall in the 13.5:1 range. I've never built anything with that much comppression. I have got alot of interesting insight from your video, especially when you spoke of boosted applications on pump gas. I'll break the cam in, flat tappet solid, with Torco 112. Once the preliminary break in is performed I'll do a compression test to measure pressure. Thank you for the info.
13.5:1 with a dome isn’t ideal. The dome interferes with flame travel. Shoot me an email if you’d like some guidance on how to improve the combustion event and make the chamber work better with the dome. TheGT350garage@gmail.com
I watched the video hoping to hear some talk about Quench. Maybe I missed it. I am building a 460 Ford bored .040 over. The pistons are .036 below deck so I am having the block milled .036 to zero deck. With a Fel-Pro head gasket with .041 compressed thickness I will have .041 Quench. With my Dove C heads I will end up with 10 to 1 compression and hope to run regular pump gas if possible. If not I have some D3VE heads with 20 more CCs in the chamber which are more pump gas friendly. The problem is the D3VE heads need guides and also the pedestals converted over to studs for my roller rockers. This will cost some $$$. Hoping I can use the DOVE C heads cuz they are ported and ready to go with bronze guides.
I’m guessing you’re using a later 10.322” block and you don’t mention which pistons you’re running. If you have a flat top with eyebrow reliefs and you cut the deck to 10.300 you will be just over 11.2:1 compression. A dish will obviously be less, and the shape of the dish will play a major factor in combustion efficiency, by which, anything other than a dish that matches the shape of the combustion chamber will reduce quench area and impact flame propagation in the dish portion of the overall combustion chamber space. The reason I wouldn’t cut .036 off of the deck is because with the large bore on a 460 the piston will rock on the pin in the piston to cylinder wall clearance space and you get dangerously close to contacting the head with the piston at TDC. A big bore like the 460 needs .055-.060” piston to head clearance to avoid collision, but that’s still great for quench. Quench is a whole concept to itself that I will cover at some point in a future video. I’ve had some challenges getting content made for a while now, but I’m working on it.
@@TheGT350Garage Thanks for the advice. I have a set of Silvolite 1143H.040 with a +21cc piston volume. The block came out of a 1973 Lincoln Continental.
Take the deck to 10.300” and the D0VE-C heads. Take what you get for compression and quench. That piston is generic, the dish isn’t ideal, but the combination will work better than it would with the D3 heads.
@@TheGT350Garage I really appreciate the advice. The block is at the engine shop waiting for the pistons to arrive so they can mic them for the finish hone. I know the pistons are cheap ($220 for eight) but they are the only ones Summit had that were close to the CCs I needed. Diamond & Icon cost over a thousand a set. Keith Black also expensive. I will tell the machinist to go 10.300" and hope it runs ok with the Howard cams 240705-12 roller cam I plan to order. Thanks for your help
Honestly I would have used a Silvolite 3191H, compression isn’t the enemy. On 3.85 stroke with a 6.605 rod you’re .018” down the hole at TDC in. 10.300 deck, with a Felpro 1018 gasket. With a D0VE-C you’d have been right at 11:1. Your cam choice doesn’t have nearly enough duration. In the 10:1 to 11:1 compression range a street profile should be in the 234-238°@.050” range on the intake with an exhaust duration no more than 6-8° more than the intake, the ICL needs to be at 112-114, with an LSA of 108-110° and .580-.600” lift on both sides.
We are just finishing up on 1964 fairlane 500 sport 289 c4 with 289 one dot heads with 1.84 ans 1.54 valves light ported big question on fuel and timing I'm almost 70 have building engines from 17 . the new cam profiles have thrown me on this one . talking to different people they said total advance should be 28 to 32 it did sound right to me . thank you for your info . maine .
That head has a small compact chamber but it’s a less than ideal shape. Depending on the pistons and head gaskets you chose and how you machined the block you should have no more than about .055-.060 quench. That keeps you out of trouble. Don’t run a traditional spark plug in that engine. I use the much colder Autolite Racing AR32 gapped at .032-.035” and it makes a huge difference in fuel sensitivity. It’s not the cam alone, it’s also the fuel that drives the timing down into the 28-32° range. Make sure you’re using vacuum advance On manifold vacuum and the engine will run nice and cool.
Very informative, you really appear to know what you're talking about, I'll be applying what I've learned today, I'm building an engine and as it turns out i was concerned that i might be a little over 10:1
10:1 is absolutely fine as long as your quench clearance is .040-.060”. Any more than that and you start getting detonation in the quench area. If you’re using a dish and it doesn’t match the shape of the combustion chamber that’s also problematic. But 10:1 is a good starting point. You want to make sure your cam duration and specifically the opening and closing events produce the ICL, LSA and thus overlap you need for best results. People tend to get in trouble by using too small a cam or running a larger cam that leans towards building too much cylinder pressure in lower to mid range operation, and that too complicates the process.
@@TheGT350Garage it's actually a 1.8 ltr. mgb engine, very slight dish, 6cc, kidney shaped chamber. Presently at about 9.5:1, runs great on 93 octane but below that, I really have to back off the timing. the head is cracked across two seats, been running fine for the last 20k but feel like it's just a matter of time before it fails. I acquired another head but later found that it was skimmed .060 and think it would take me above 10:1. I have I new stock cam and runs great, smooth idle. Do you think a light porting would positively tone down posible detonation, thanks in advance.... Luc S...
@lucsavoie9501 port the skimmed head lightly to improve airflow, simply working in the bowl to contour the guide bosses and remove any casting flash or machining peculiarities in this area of the port and profiling the combustion chamber to unshroud the intake valve, and lay the deck back down to the seat with a gentle transition inside the gasket opening along with getting a slight 1/16” or so radius on the chamber anywhere it’s exposed to combustion combined with a proper valve job, and you can make big improvements in about 4 hours time plus the valve job. Then get a “Fast Road” type cam with duration in the 260-270 range to take advantage of both the compression and flow, you’ll have a very fun little combination. The one thing to consider is the piston to deck clearance, I generally build to 0.000” and set piston to head clearance with the gasket. Ideally you’ll want 0.032-0.035” clearance, if that clearance is more than that because the piston is below the deck, and you can’t get a thin enough gasket to get in that range, consider decking the block. It will further increase your compression but substantially decrease the likelihood of detonation in the quench areas.
Great video! Thanks! So this video would seem to be a lead into how to shape a combustion chamber (maybe among other things). I just subscribed so haven’t seen what you have for other videos yet, but will, but if you need new topic and it’s not covered in current videos, that how to shape a combustion chamber would be of interest. Thanks!
Very interesting and informative, great to hear as I'm currently working on a 11.8:1 4.6l and was worried I'd be stuck using e85 or water methanol. Can you clarify exactly how you are using the specific heat ratio? You stated the cranking pressure in the cylinder was equal to the product of compression ratio, atmospheric pressure, and specific heat ratio (Ptdc = Patm*CR*λ) and thus removing the effects of heat addition from compression would require dividing by both the measured cranking pressure by the specific heat ratio and atmospheric pressure to obtain the dynamic compression ratio (CRdynamic = (Ptdc/λ)/Patm). This would only hold true if the adiabatic process were linear (P*V*λ = constant), which is not accurate. I think what you may be referring to is the polytropic process relation which is P*V^λ = Constant. Thus the equations from your examples should be Ptdc = Patm*CR^λ and CRdynamic = (Ptdc/Patm)^(1/λ) respectively. For the second example worked out that would be CRdynamic = (155psi/13.6psi)^(1/1.4) = 5.68, significantly lower than 8.1. The relation between pressure and temperature is linear. However, within a confined space, as temperature increases proportionally withpressuree, the heat created causes a further increase of pressure which in turn causes an even further effect on temperature and so on. This results in an exponential relationship when gas is compressed in a confined space, an exponential relationship with a coefficient equal to the specific heat ratio, 1.4 for air. en.wikipedia.org/wiki/Polytropic_process
I appreciate the thought that went into the comment but there are other factors you aren’t considering. The ethanol content of the fuel has a cooling effect that negates some of the heat, as does the pressure drop into the cylinder, much like expanding a refrigerant to create air conditioning, the void created as the piston moves down the cylinder is going to cause a low pressure for the air-fuel charge to expand into and that too will cool things down, so it negates much of the heat you’re adding in using polytropic calculations. Sometimes it’s better to simplify than over complicate. This is one of those times. Otherwise we would have to calculate the rate the cylinder volume increases and plot that against the flow of the cylinder head, at which point we would see that the expanding volume is greater than the head flow initially. Then we would have to factor the speed of the crank, the length of the rod and the acceleration and deceleration of the piston against the speed and mass of the airflow, at which point we could roughly calculate how much air flows past the valve while the piston is in a practical state of dwell near BDC. Easier to run a compression test, take a pressure and see that it is more or less efficient than the static compression ratio as a determination of overall pumping efficiency and potential volumetric efficiency / performance.
I never was to much for going by what some book told me about setting Fuel or ignition timing! What I did find was I make the most power, the best ET when my plugs are the right color, and the ignition burn is on the curve of the ground strap of the plug. What I did find is the timing is about 4 * less with today's 94 octane than it was with the old premium. I used to run 36 * now it is around 32*. i thought it was because of the Aluminum head I use now.
The difference in timing is primarily because modern gasoline burns faster and more completely. Reading plugs is a good start, but it doesn’t capture the complete picture. Ideally, a tuning session on an engine or chassis dyno is the best way to find the ideal A/F Ratio and timing curve. But when those aren’t readily available, you can use a wideband oxygen sensor, a pyrometer (EGT Probe), and a simple stop watch to find exactly what the engine likes.
I have done some experimenting with varying comp. ratio's. Intake valve closing is important to how much charge is trapped in the cylinder affecting the dynamic comp. ratio. Playing with high comp. and short timing on cams for cyl. pressures of 210 220 psi was an experiment for economy. This motor needed nothing but standard tuning at 5000 ft. but under load under 1000' was preignition. Using water/meth injection stopped preignition. Later a longer cam install completely cured the issue. I run an old Ford 351C on 11.3 comp. with iron heads and the camshaft makes it work great.
If a 351C uses a relatively flat piston and has .035-.050” quench with a closed chamber, that’s most of the battle. 11.3:1 needs an IVC event around 75-85° ABDC at .004-.006” (286-294° Advertised Duration) or 45-55° ABDC @.050” valve lift using a cam with about 234-238° duration @ .050”. ICL needs to be 112-114° at that duration to close the valve in the correct window. Using an LSA of 108 or less is too tight and disrupts idle and causes drivability issues, 110-114 depending on the final duration number is the range to be in to manage overlap, 116 and up is unnecessary except for extreme setups trying to run 255° @ .050” or more on the street, and there’s no benefit to a cam that large below about 13:1 compression. Cam specs are super important, but following some of the long time standard advice to advance the cam and tighten up the LSA is not conducive to quality results and just nets a lousy idle quality and pesky torque curve. My little 2.3L DOHC builds 20 or so years ago were 11.5-14:1 compression. I ran durations ranging from 226-256 @.050” and degreed them on install but adjusted them on the dyno to optimize power. Each grind had its own characteristics and each compression ratio had its ideal grind. At just under 140” displacement, to make 285-315hp at the flywheel naturally aspirated in the 7500-8200rpm range depending on the build was a pretty decent result back then, and most of them ran exclusively on 91 Premium pump gas. My 12:1 “street” build was 265hp on 87 octane and managed 35mpg on the highway at 75mph or so. Funny side note, the 2.3L DOHC heads ported flowed more than a lot of 4V Cleveland head with epoxied runners and port work, and with near 4” of stroke the ports moved a lot of volume, we were regularly over 100% VE with those engines.
Very helpful, I have a 1968 AMX with an over bored 390 at 11.7 -12 comp ratio static, with cyl compression tests at 200 to 205psi cold. The cam is an old sig erson solid lifter 320 hi lift w 45 degrees overlap, induction is a low profile dual quad offy with a pair of 500cfm carter competition carbs, I can also run dual holley 650's or a single holly 850 carb on a torker manifold. I believe a tunnel ram would work best but I don't want to cut my hood for the street as I could get pinched for vision issues.Pump gas detonates at idle, and has been the biggest headache to deal with. Also with electric fans and a flex fan with a shroud she runs hot. Oiling is a high volume milodon with a scanne rand cooler, and valve timing can be adjusted with the gear drive . ignition is MSD or a crane Hi fire. on a mechanical advance only distributer Where do you think is the best place to start, I've considered fooling around with the valve timing and advance curve. The car runs rich and doesn't bog if the clutch is let off a 3,500 rpm but pulls best starting at 4,500 rpm to red line, the engine can do more to 8,500 rpm before no more power is felt but then the mains are trashed. I also considering a hyd street roller cam if there are any for AMC, and running a single carb maybe a 750 cfm vacuum 2ndrys to calm it down for the street. Any thoughts.
I thought I had responded to this, so apologies for the delayed response. The cylinder pressure is a little higher than some like, but not terribly so. If it’s not beating up valvetrain parts, it’s probably ok to keep the cam and compression where it’s at. If you’re at sea level, 14.7psi, you can determine the effective compression ratio from your cranking compression. (205/1.4)/14.7=9.96 so call it 10:1. That’s effective, not static or dynamic. If you’re above sea level pressure drops .5psi for every 1000ft elevation. This would only mean the effective CR would be higher. If that’s an old school cam grind, the numbers may be advertised numbers and the cam may be much smaller than you think, ideally compare numbers from the @.050” duration to get a better sense of how big the cam really is. More cam could lower the cylinder pressure and make the engine easier to tune without giving up performance.
Agreed with a lot except the muscle car era from 64-74 considered 8:1 high compression. From 64-70 the compression ratios were almost always over 10:1. After 70 they continually dropped
The cars from 72-81 that were still remnants of the 64-71 era were all neutered by emissions laws, but those cars are often upgraded to use higher compression ratios and have their emissions equipment removed. It’s nitpicking at best to include those lower compression ratios in the discussion as “muscle cars” because the muscle was gone and they were just cars at that point.
I’m really enjoying these videos! My 69 Mustang has a 351W with a carb and stock distributor. I bought some old school tools NOS - a vacuum gauge, timing light, dwell meter, etc and I like trying to learn what seems to be a disappearing set of skills…..These videos really help us out here! Keep up the great work!
You are in luck, because there are more videos coming to dive into how ignition timing can needs to be set up, how to address the various functions of carburetors to achieve ideal air fuel ratios under various conditions, and how to use the tools that are necessary for making it all come together.
Hi Walt. Guido here. I am running like 5 gallons E85 to 10 of 91 chevron here in SoCal. With that amount of Corn fuel. Do I still adjust on my 4160 holley 1.5 turns out for Air Fuel mixture or a different setting Keep up good videos. Running 12 Degree initial. Total about 28-30 I believe.
@@luckyluciano4968 we should talk about this witches brew of fuel you’re using, it’s too hard to duplicate if you find yourself in need of a refill. It’s far better to run a commonly available grade and tune to it. I suspect you’re probably quite lean with that mix unless you’ve jetted up substantially. And that concoction would require substantial changes to the carb to make it meter the correct amount of fuel, beyond jetting, you’d need to get into the air bleeds, the PVCRs and do a fair amount of tuning. Your timing is in the range for a 10.5-11:1 compression combination, but until you get on top of the air-fuel ratio and get it optimized to the power potential of the engine, your timing settings are a wild guess at best.
@@TheGT350Garage I havnt jetted differently I was just trying out the E85. It’s a stroker 331. Is it spec out at 10.5-1. Coast High Performance in Gardena. Built the engine back in 2014. I don’t plan to keep it in the system. Gave it a little more pep. Havnt mess with anything Thanks for your input.
Just to put this in the simplest terms, 5 gallons of E85 (85% Ethanol) 108-octane mixed with 10 gallons of California spec E10 (10% Ethanol) 91-octane will produce E35 (35% Ethanol) 95-octane fuel. While that seems “good” it’s really not because you have to look at the effects on the stoichiometric air fuel ratio for each blend and that’s what determines what is rich or lean for the fuel. Gasoline has a stoich point of 14.7:1. Ethanol that has a stoich point of 9:1. When you blend them the stoich point “moves” with the blend ratio. E10 (10% Ethanol) 91-octane has a stoich point of 14.08:1. E85 (85% Ethanol) 108-octane has a stoich point of 9.85:1 Your E35 (35% Ethanol) 95-octane fuel blend would have a stoich point of 12.70:1 A 331 Stroker with 10.5:1 compression and a typical street type hydraulic roller cam grind (425-450hp) is going to make its best power on ethanol free gasoline at an air fuel ratio of 12.8:1 to 13.2:1 and 32-34° of total timing. The timing would stay relatively the same and at most 1-2° less depending on the fuel used for any of the various aftermarket head options and their different combustion chamber designs in concert with the various cam profiles that would all result in similar performance. What’s important to realize is that for the engine to maintain its full power output capabilities, you have to maintain the same amount of fuel energy and that’s why we need the Lambda number I talk about in the video. So knowing that straight gasoline with a stoich point of 14.7 makes best power at 12.8-13.2 we divide the A/F ratio by the stoich point to get the Lambda value range of 0.87-0.90. If you apply that range to the ethanol blends we’re talking about, here are the numbers: E10 91-octane (14.08) 12.5-12.7:1 E85 108-octane (9.85) 8.6-8.9:1 E35 95-octane (12.70) 11.1-11.4:1 In this day and age you need to verify the air fuel ratio of your tune. It’s just flat out important. And in most cases, you will need to adjust the carburetor jetting to optimize the air fuel ratio for the fuel in your region. Being in SoCal, you can’t get Ethanol-Free fuel that meets CA emissions requirements. Here in the Rockies and all over the midwest, Ethanol-Free is commonly available, and at the lower elevations with as much as 93-octane. These are the challenges of tuning cars on modern fuel. It’s not that the fuel is bad, it’s just more complicated. If you can take the time to understand it, it’s actually very capable and will do what you need it to do for you.
I use @.050” values not advertised because advertised values are really inconsistent from cam to cam. The cam manufacturers have enough variation in their advertised numbers that they’re basically useless for comparison or any true closing point determination. Also, at .050” the valve presents as closed to both sides.
I'm going to use a AFR gauge to help my tuning process. My new build is LEAN on the plug and it has many hiccups in the slower throttling process. This info is great. I have a friend that says modern fuel is trash. I argue with him about it. The carb I was running on a stock engine worked great. New carb, not so much. I've made soooo many changes to this engine it doesn't want to run hard past stall speed of the converter .
Once you pass the stall speed, the load on the engine increases. You probably need to look carefully at timing as well as fuel. I would suggest a vacuum gauge as well as the AFR info, you can judge load from vacuum, and you can use that to judge the appropriateness of the A/F you’re seeing.
Thank you for this video!!! I just had a Studebaker Avanti R1 engine custom build for my 1955 Studebaker Commander Coupe. My son and I will be breaking this new engine in shortly. It is suppose to be 10.25 t0 compression ratio, so I am concerned about timing and carburation. any ideas you might have will be welcomed. thank you again Steve clark.
Very informative, 10:1 is common on euro cars and I’ve had several. I now understand the octane rating better, when I was 16 I had a 2007 328i that should have been running on 93 octane. I ran it at 87 or less and ran it hard, for a bout a month. Couldn’t figure out the knock and overheating issues. Now my 2003 330i runs ethanol free 91 octane only with no issues 😅
Absolutely great Informative video !!.....I've been searching the net for the elusive Compress air Heating Factor (1.4) & You clearly provided it.....The "On Line" Dynamic CR calculators are all over the map, typically using 0.050", cam card lifter Check Height or Unspecified IVC input data, None of which is Actual physical Intake valve Closed timing point.....They all Can't be Right !! .....Even if you Use the Actual correct IVC, at typical Cranking Rpm, the valve Overlap Is allowing the Air/Fuel mass Inertia "Plug" to slightly Overfill the cylinder Beyond the Calculated IVC cylinder Volume.......I always Suspected the typical Calculators are computing an Erroneously low Dynamic compression ratio figure....This new computing method may be more Accurate than the various IVC Calculators......Thx for the Helpful video......
I teach engine controls and that includes VCT/VVT operation modes. Newer production engines are using late intake valve closing to produce Atkinson Cycle operating conditions. To operate in that cycle the closing event needs to be able to move from as little as 30° ABDC to as much as 120° ABDC seat timing. My cam isn’t “huge” and it closes on the seat at 81° ABDC, 55° ABDC @.050”. The way the calculators determine dynamic compression simply lacks any accounting for the rest of the physics involved and completely ignores the compression to expansion ratio of the engine which is equally important.
The principle applies to most engines. There are always exceptions, but I’ve used these methods on Ford, GM and Mopar engines with solid results. I’m working on a follow up video on how to dial in the timing curve step by step that I hope to have up in a week or two. The process works, and I’ll show some great examples in the process.
That all made sense (I had to rewind quite a few times). My question is; do the same rules apply to tuning lower compression engines. I have recently rebuilt my 1962 Triumph 650 which has an 8:1 c/r. By chance the new carburettor came with a 2.25 (?) jet where as my old one was 1.8?. There was a fair guess made at the timing advance as the notches in the gear do not match the positioning stated in the manual so "the right sound guage" was used. Can I assume that having the larger jets will paper I er the fuel density issues of using E05 (95RON) or E10 (97 RON). Note that in the UK there is a 5% price hike on E05.! Also will adding an ethanol fuel conditioner affect the fuel density factor to any noticeable degree. Thanks. Mark
So, ethanol isn’t quite the demon it’s made out to be. It has some positive effects on combustion including better vaporization which has a cooling effect on the combustion process. Most “Ethanol” conditioners or additives for ethanol fuels are just methanol and fuel system cleaners. If the car will go into winter storage for more than 4 months, I’d use Sta-Bil or an equivalent product to keep the fuel fresh and fill the tank to 95-97% for storage to limit the amount of air that can oxidize fuel. Otherwise there is t much to be gained from ethanol fuel additives. As far as your jetting, you typically need to jet up a bit for E10, and that could do the trick. Also, your new carb may have a slightly more modern calibration to combat not just the changes in fuel, but also to run an air cooled engine a bit on the rich side to manage cylinder temperature better.
@@TheGT350Garage Thank you for your advice regarding the additive route. The carb is a new AMAL and for your advice on running a bit rich. I'd wager that there is no refining of the carb....🤭
Great video but I would like to see some actual hands on tuning, how does the typical guy tune a carb and timing without a Dyno or high dollar equipment that the average person can't afford? I'm not complaining it's a great video. Tks.....
That’s in the works for sure. The distributor curve video I did shows how to make the change’s internally in a Ford Autolite or Motorcraft distributor, Mopar and AMC are very similar, GM is easier. As far as the process of figuring out where you are and where you need to be, that is a video that is waiting for me to have a running engine to film the process, and the same goes for carburetor tuning. Now, I will say, there are some basic tools at minimum required for tuning, timing light, vacuum gauge, but you will also need a wideband air/fuel ratio gauge and sensor. It’s a small expense relative to dyno time and stays with the car. All of this will be covered as I get the car out on the road for tuning. A final item is a g-meter and stop watch or digital accelerometer to measure acceleration over time, which is exactly what a dyno does. You won’t get an exact horsepower or torque number but you can measure gains or losses from changes to air/fuel ratio or ignition timing, and that’s more than enough in most cases. I’ll cover all of it in detail soon.
Gotta pause at 25:53 to say that's not how reduction works. Reducing by 25% numerically is not the same as doing so mathematically. 10/1.25 is 8. Just the same as 8*1.25 is 10. If you remove 25% (this is different from reducing by) then you get, numerically 7.5, yes. But that is a 33% reduction. IDK what this phenomenon is officially called, but I call it inverse decimals. *Post view EDIT:* Okay, so if we have a choice in the matter or need to make an informed decisions, what part of the octane rating is more important for enthusiasts? The RON, MON, or AKI? I would assume MON since that's based on higher load and unfavorable intake temperatures, signifying a worst-case scenario. Also, given this inquiry, once decided, is there any direct correlation between octane rating and compression? IE does an 86-88 MON rating mean that I can safely run 8.6-8.8:1 dynamic compression, or is it indeed, higher, more line with the AKI or RON rating?
If you have 100 apples. And I take away 25% of your apples, you have 75 apples remaining. You’re calculating the difference between the final product and the original product and if we started with 7.5 and wanted 10 it would require a 33.3% increase to get 10, but we are subtracting or losing 25% here, so it’s 7.5:1. Comparing fuels is challenging. AKI is great for pump fuel, but race fuel in a can requires you to do some research. To call it “race gas” RON will be 100+ and AKI will be 96+ but even then it’s not that simple.
@@TheGT350Garage Fair enough... Though you didn't really hit on MON since it's rated under extreme stress (300 deg plus intake temp, 50% higher rpm) compared to RON(120 deg intake temp). Wouldn't that be a better metric to look at for performance engines? Seems like if the MON is particularly high, that means the fuel would be particularly less likely to grenade your engine under driving conditions that would cause catastrophic failure in the first place. Another thing that I've read, and this is from David Vizard, himself, is that water has "infinite" octane, and therefore water injection (not even water/meth, he says JUST water) can allow you to run up 14:1-17:1 on 87 octane fuel. What's your take on that? Is that even useful for the street or no?
@Drunken_Hamster David Vizard is brilliant, but there is a point where practicality has to be a consideration. What happens if you are driving and you have a water injection system failure? If you tune for water or water/methanol, you have to rely on the system to keep the engine from experiencing detonation, I’m a fan of simplicity, and water injection is not conducive to simplicity. As for MON, it’s not as readily accessible for fuel information as RON or AKI. AKI being the average is honestly the better choice for comparison across all types of fuel, but performance fuels don’t always include the information in the documentation. Again, simplicity being key to success, using a single standard for measurement would be ideal, but this industry isn’t as good about getting together and adopting standards as it could be.
@@TheGT350Garage I thought so on the water injection part. And thanks for the perspective on both! I haven't watched your second video yet, but it's in the queue. After all, I might end up throwing a 302 or 331 stroker in my Ranger some day and I'm learning a lot beforehand so I can do it right and put the whoopin on them 05+ muscle car boys. Especially them fat Mopars and my brother's 2012 SS.
Sir, I have a question, My VW 1.0 TSI has a compression ratio of 10:5:1. It says "Minimum RON 91, Recommended RON 95" (these are for EU spec,,, for american spec would translate to 87 and 91 octane respectively). Am I ok with 91 RON or should I be religious with 95 Octane? I want to hang on with the car for atleast 200K miles. I am a very sedate driver, always drive on the highways and almost never exceeding 2.5K RPMs. What do you say?
It’s easier to extract the potential from a lower octane at lighter demand. With 91 RON being the “Minimum” per the manufacturer you’re certainly safe to use it. If you were working the engine harder, you’d want to use the 95 RON. Choose a top tier fuel (a brand or brands recognized for selling a higher quality product) and perform your scheduled maintenance on time or a little early.
Hi and thanks alot for the info. Engine head I did a few years ago and not knowing how to measure the chamber turns to result in 12.87:1 comp ratio (it's been 9.5 stock). Also running an old racing cam, lots of duration, not to big of a lift and it should have some bigger overlap resulting in lower dynamic comp ratio. I tought I will dump the head or take some meat from near the intake valve to make the chamber bigger. I will try to measure the cam so I know exactly what I am using. I will watch this video again to try to have a better understanding on timing I should use and jets. Also, I heard "because of that high duration cam you need stiffer distributor springs or remove the vacuum advance from the distributor and preferably an adjusting cam pinion". What do you think about this? (I wrote this before watching the rest of videos to not forget something). Also, I don't have enough money for special made stiffer valve springs to prevent valve flow. I saw some guys putting shims under the springs, what do you think? Wanted to add that the engine it's not yet built. Thanks for the intel, can't wait for new stuff to be posted!
Blew my mind.totaly covered things I've often thought about but never found out.very very informative.thanx..im 13.7 to 1 with lots of the issues you mentioned. Mainly 110 octane on the street at 5 mpg@9$ a gal. It's parked on you tube @. Ole ridge runner race truck
While it often gets called de-tuning, the reality is that tuning is finding what the engine wants. Here’s a little food for thought: 9:1 static compression is calculated using 14.7psi atmospheric pressure at sea level, which is why a typical 9:1 engine pump’s slightly higher than 150psi (9 atmospheres + 1 atmosphere). Take that 9:1 engine and supercharge it with 7.5psi manifold pressure. That is roughly 1-1/2 atmospheres. Now the engine is compressing 14.7+7.5 = 22.2psi. 9:1 at 22psi is close to 220psi and we ran that on supercharged 5.0L HO Fox Bodies in the 90s with minimal tuning. Your 13.7:1 compression is not much different except for it being there all the time not just at high rpm. 13.7 atmospheres + 1 atmosphere = 216psi. There really isn’t much difference difference between tuning a 13.7:1 450” engine and a 9:1 300” engine with 7.5psi, they both have about the same cylinder pressure, if one was a 351W based stroker and the other was a 302 based forced induction engine, and both used the same head and combustion chamber on a flat top piston, you’d be shocked to find that while the forced induction engine would have a higher BSFC the timing would be nearly identical. The point being that if you can run a supercharger and have the equivalent of 13.7:1 compression on 91-93 octane, you can run 13.7:1 on pump gas if you take the time to understand what the engine wants.
I run a 540 chevy in a nova with 11:1. Solid roller, all the goodies. 850 hp. I run Holly FI. So nice and tunable. I use 94 ultra. 13.6 af and 30 degrees total timing. No problems at all. Nice thing is i can alter my af for different fuel if 94 is not available. 91 octane i run at 13.8 with 32 degrees timing. Very fun car to drive.
Might want to rethink the idea that 91 can be leaner and have more timing. That’s not usually the way the fuel responds. 94 Ultra has a stoich point around 14.2-14.3, and 91 will be closer to 14.1-14.2 depending on the source and season. That puts you at .95-96 Lambda on Ultra 94 and .97-.98 Lambda on 91 octane, which, respectfully, is a recipe for disaster. Even “IF” stoich was 14.7 and there was no ethanol content in any fuel you were running, you would be at 0.93 Lambda on Ultra and 0.94 Lambda on 91 octane. Most high performance naturally aspirated engines need to be in the 0.86-0.89 range to be safe for regular use on the road, especially in the transitional range below to just above peak torque.
I ran a Pontiac 350 with 10.5 compression with a 274xe with 110 lsa . I ran it with vacuum advance . Total mechanical timing was 34 degrees when the vacuum pulled in , it was at 47. I ended up squashing the piston rings and deforming them ...losing compression. Pulled the engine and got a 400, bought TRW pistons and tool steel piston rings capable of withstand 48,000 lbs of pressure without damage. Also bought a summit cam RAIV can 235/245 112 lsa. Set the timing at 34 total, ditched the vacuum and plugged it. Runs well, but if I run 89-91 octane, it's very hard to start when hot. If I add 102 real race fuel, it starts with one stroke of the crank. Obviously octane makes a huge difference. It still has 10.5 compression
The only way you can get 47° under load with vacuum advance is running ported vacuum. Manifold vacuum will be 2” or less at WOT and you’ll have 34° at WOT. That’s why I take the time to explain the difference, and if you skipped through the video you probably missed that part, and your comments would be more about the mistake you made using ported vacuum than trying to blame vacuum advance piston failure. You probably have too much initial timing and likely have a secondary issue with your starting circuit causing slow cranking. The only reason 102 “real race fuel” would make it start better is if it had a lower ignitability that caused it to make combustion pressure later or after TDC. Back the initial timing off and 91 octane will make pressure at the correct time for the engine to start normally.
Didn't mean to misguide the port vacuum with manifold vacuum. I installed the vacuum on the manifold, so when the engine is at WOT the vacuum goes to zero. It's when you start letting off the the throttle gradually, the vacuum goes sky high along with it goes vacuum timing , now your banging at 47 degrees and fuel is still moderately rich, causing detonation. I heard it with my 350 , not going to grenade my engine to try to experiment. I'll take the loss of HP, unless you have a way of doing it that won't destroy my engine . Good video , just a little hesitant.
@@johnszoke586 there is a reason I’ve made a good living tuning engines and now I teach and develop training for engine performance, drivability, and emissions compliance for one of the largest auto manufacturers in the world. Not bad for a guy without a degree. Your issues are not unique to your combination, and they are all correctable, without the need to perform experimentation or put the engine at risk. I do these videos to help people like yourself learn how to get the best from their setup, not to argue with them. The only way that works is if the viewer has an open mind to listening and learning. If you ask for help, that’s what you get, and if you complain or argue, well…
It’s all in the camshaft (valve timing) as to not trap too much air in the cylinder. I ran 11:7+ on pump gas in the 80s in a Cleveland ford engine with nothing special , just a cam designed for good pump gasoline. Keep you cranking pressure down with overlap and timing. 12:5 static is no problem. Call your grinder if in doubt.
Cleveland 4V with closed chambers wants compression. The improved combustion pressures get the ports activated because the piston on the companion cylinder accelerates at the same rate as the piston on its power stroke. Bigger cams become more effective as a result. It’s not about valve closing and dynamic compression though, that number is actually pretty meaningless, and the only reason it continues to be used is because everyone wants to run too much ignition timing at lower speeds and detonation is the result. You talk to cam grinders and they all push advanced cam installations, yet the closing point is the supposed secret to success with respect to cylinder pressure, and those two things are in conflict. I’ll be sharing my full thoughts on dynamic compression in an upcoming video and it’s going to explain a lot about how the engine combination works and why dynamic compression is utter BS.
Great video! Love the true/accurate information on how to exactly measure by providing proper formulas to meet the engines needs based on usage. Two questions, 1. How do we adjust fuel enrichment and the taking of timing out based on weight of vehicle to avoid detonation issues? 2. Do you have videos on how to match a camshaft to the vehicle for getting the best performance for a street machine? I have been struggling to find a complete video or set of videos on how to find proper LSA, duration, etc. for example, David Vizard is a believer of lower LSA for small block chevy’s e.g. 108°. He claims great performance, smooth idle,etc. But, all the pulls on the Dino start at 2500rpm. Thank you!
So, I did a follow up video where I explained how to use Lambda (combustion efficiency) instead of air fuel ratios for adjusting fuel. Ideally you’ll be in the 0.85-0.88 Lambda range for optimum performance on pump fuel. Lambda is independent of the stoichiometric ratio of the specific fuel you’re using, because it focuses on the completeness of the combustion process for the specific fuel you are using. Adjusting timing and fuel should be a rough timing adjustment somewhere less than you would expect peak power (2-3 degrees less) prior to adjusting lambda into the 0.85-0.88 range, then a fine adjustment to timing to get peak torque across the range. As for cam selection, I like a wider LSA than DV recommends in most cases for a street car. Typically I like a 112° LSA on a SBF. But in conjunction with the wider LSA I also prefer the ICL to be in the 112-114° range, not the 102-104° range that gets so much attention. What I’ve found is that the ICL has a far greater impact on idle quality than LSA, and simultaneously running the ICL about 10-12° “retarded” improves cylinder filling at higher engine speeds extending the usable power range while also improving idle quality. Just retarding the ICL would also retard he ECL but increasing the LSA advances the ECL. For a cam with a 110° LSA using an ICL of 110° ATDC, you would have an ECL of 110° BTDC. Example 1: Retard the ICL 4° to 114°ATDC and the ECL moves to 106° BTDC on the same LSA of 110°. Overlap does not change. Example 2: Widen the LSA to 114° with the same ICL of 110° ATDC and the ECL moves all the way to 118° BTDC. Overlap reduces 8° Example 3: Retard the ICL 4° and widen the LSA 2° to 112° and you get a cam with an ICL of 114° ATDC and an ECL of 110° BTDC. Overlap reduces 4°. In example 3 you retain the same ECL and this the same exhaust closing event, which is critical for scavenging the cylinder and creating a vacuum in the cylinder at TDC. By opening the intake valve 4° later you spend less time with the valve hung open during piston dwell at TDC and ultimately produce a better idle quality. It’s often argued that retarding the cam is only done for emissions and that it hurts low speed torque, but I’ve found that the losses are negligible off idle and the overall power delivery is more linear and efficient, with substantial gains to be had in average power across the range, and often 600-1000 more usable rpm at the top end. The one caveat to all this is you need to set up the vehicle correctly to make use of the power curve, and the rest of your components need to match your engine combination in a complementary manner.
@@TheGT350Garage I saw something about Lamda toward the end of this video, but how do you adjust it to weight of car? Heavier the car or truck, the more susceptible to detonation. (Maybe you answered this already and I am not understanding)
I really love your approach. I have a 403ci small block Chevy. I was wondering if you have an email I could message you privately to pick your brain some more. I have built engines before, but have not gone into this depth to get the most out of the engine. I would appreciate it if you would be willing. Thanks!
So, I do have a follow up video detailing the difference between fuels and focusing on the importance of Lambda. Basically lambda is a measure of combustion efficiency where ideal combustion is the relative stoichiometric ratio of the fuel in use. Most performance applications will make optimum power from a Lambda value of .85-.88 with rare exceptions getting as rich as .82 or as lean as .92 lambda. You’ll want to target a timing value 3-4 degrees below optimal for dialing in fuel, get in the range for fuel and then dialing in more timing, readjust fuel, and repeat. Ideally a loaded dynamometer is the fastest and easiest method to dial it in, but any method of measuring acceleration over distance and time will suffice as long as you test in a repeatable way under the same conditions.
Specific heat is a physics a thing that applies to different gasses. For atmospheric air, it’s a multiplier of 1.4 (nitrogen and oxygen are both 1.4 and make up 99% of atmospheric air) and factors into the temperature and pressure increase. I have a video coming up soon that will dive much deeper into compression.
Excellent content long time old racer here and what your talking about is true about dynamic timing with cam event timing . It’s easy to make power with boost it’s almost cheating I still like NA with 100% methanol . After track testing only ign timing after 33-35 degrees has no effect on MPH In my case . 14.1 Compression ratio mechanical injection SBC. Thank you.
Every fuel behaves differently but all fuels are predictable. Ignition timing is mostly about getting the peak cylinder pressure in the right place, some engines even like a bit if high-rpm retard. Cam timing is another discussion completely, and one that has to be had when discussing cylinder pressure and ultimately ignition timing. 35 years of doing this and I’m still learning new things, things that cause me to try new ways of approaching engine building and car construction as a whole.
@@TheGT350Garage you are 100% I’ve been racing since 1971 still racing have a national record still feel I’m behind .I’m impressed with your knowledge and that’s hard too do.
If you are increasing it correctly by reducing quench areas you’ll be fine. Ideally you’ll want a bit more cam, but if you’re not changing the cam, you’ll want to retard it a few degrees to get the most from the added compression.
The ‘93-98 Lincoln MK VIII 4.6 DOHC engines are tuned for 14.7:1 air fuel ratios. If you’re having starting issues with E10 fuels, that could indicate other issues. With E85, it should barely run if it starts at all on the stock tune. E85 without tuning will set lean codes. I teach modern diagnostics for a living, there will be codes and a diagnostic path to follow if you use the OE Ford/Lincoln service manuals and the correct diagnostic tools for the era.
I watched a video by David vizard about ignition timing that confirms everything you was saying about timing. Another thing that comes into play is bored size and chamber size/shape. The more efficient the chamber shape the less timing you need which means less time for knock to occur
I’m doing a couple of follow ups to this video. I’ve decided I need go into far more detail about ignition timing with one, and dive deeper into the fuel discussion in another. I’ll also be doing some additional video content that will simultaneously support my assertions in this video, explain the content I’m sharing better than the presenters, and probably stir up a bit off a fuss unintentionally.
I used to, but don’t now. Remote tuning on EEC-IV stuff was a headache, but the ‘96-10 OBD-II cars were doable, if the owner installed a Wideband O2 and set up the logging correctly,. The ‘11-up engines are fairly easy. Here’s the issue, I don’t do “off-road” or race only tunes, and the car needs to be compliant to either Federal or State emissions. That’s almost never the case, so to protect myself against the EPA,et-al, I stopping tuning late model applications for the general public.
I run a 68 Cadillac, 93 Octane. 472 10.5/1. Gas really was low octane back in the late '70s early 80s. I used water injection ADI on my high compression engines then. The 93 Octane is OK now. It's not Sunoco 260 or 100 / 115 low lead Avgas but you can run if you don't go nuts with the timing. Want to go nuts with the timing? Run ADI.
Aluminum transfers heat out of the combustion chamber faster and more efficiently than cast iron. In a performance application this means aluminum is a little less prone to detonation if you compare two identical casings in the different materials. I’ve done this test before with World Products/Roush heads back 25-ish years ago. Same castings, same combination, different cylinder head material, aluminum made slightly less power (down 2-3hp) at the same timing and air fuel ratio. Aluminum tolerated about 2° more total timing though and because I could run that through the entire curve, the aluminum head hedged out the iron unit. If you’re building an iron head combination, shoot me an email with your planned usage and the specs and I can offer some advice to get the most out of it.
Hi Bart. Thanks for all the giudence. I really appreciate a lot. What do you think is a good oil pressure for a LS 2 stroker motor per 1000 rev's. Thanks Bart appreciate a lot. 😊
Who’s Bart? The old rule of thumb from the Smokey Yunick days was 10psi for every 1000rpm. Every application is different though. I’m building two 289 Fords. One a street / driver type build in the 325-350hp range that will turn a maximum of 6500rpm. The other is a more track oriented build in the 450-500hp range and will turn up to 7500rpm. The two builds use very different bearing clearances, and although they will run the same oil pumps they will run different oils as well. Hot oil pressure on both engines will be 60-70psi at peak rpm. Too much pressure is unnecessary and starts to cost you power.
@@TheGT350Garage I highly appreciate your support and advice 😊👍.Acording to you knowledge, Is it possible to bore a LS 6L aluminum block to 4.030. Thanks appreciate.
So, I’m not an LS guru by any means. I know you can sleeve the aluminum blocks and go fairly large, but using the stock sleeve has some limitations. The LS1 and LS6 for example can’t be bored, they have to be sleeved. The iron 6.0L blocks can go 4.030 no problem. I have to defer this to the LS experts, like my friend Richard Holdener, I’m sure one of his videos cover this, and it’s certainly covered in his LS book. I really do surround myself with small block Fords in the garage, because at work I’m swimming in Toyota technology.
Hi Walter. I did upgrade my camshaft on my LS 408 stroker motor and make good hp. Normally all the dino sheets that I can find. The torque start higher than the hp then torque drops and hp take ower. Mine is different. Torque start high and keep on rising along with hp. What can be the reson?. Just interseting to know. Thanks appreciate all your time and guidence😊. Torque start 379 to 517 at 4560rpm. Hp start 147 to 523. (On wheels)
It sounds as if you have a cam that is spreading the curve out. That’s usually determined by the specs of the cam, and depending on your application it can be good or bad. I’ve long found a broad torque curve that spreads the power over a wider rpm range can be advantageous to a narrower torque curve with a higher peak. The broad curve is typically easier to drive, but requires a little more gear ratio and a willingness to let the engine sing. It would be interesting to see more complete details on your combination with cam specs and the dyno sheet, feel free to shoot me an email if you’d like to discuss it more.
No. Because cylinder fill continues to increase to peak horsepower. Quite often peak torque happens at 10-15% lower volumetric efficiency than peak horsepower. As the volumetric efficiency increases so does cylinder fill and thus cylinder pressure. As cylinder fill increases you will often benefit from slightly less ignition timing than what makes peak torque.
Very good thank you . I’m a hobbyist to tell you where I’m coming from and a guy in a car club where there are also mostly guy hobbyists , but would like to ask you with your experience some questions as I have a 5 litre Windsor (roller cam )for the A model coupe and also I’m into air cooled vw ,on cam profiles, the stock roller cam looks good? Thanks
The stock 5.0L cam was just ok. Nothing special. It won’t really make much power unless you do a bunch of other work to the engine. Power is always determined by airflow, so the cam and stock 5.0L heads are a big determining factor for you. If you’re happy with around 250-260hp, that’s about the maximum that cam will support with those heads. Better heads like a 3-bar GT-40 iron head or would allow more power without a loss of drivability or idle quality.
@@TheGT350Garage cool thanks I see that some heads are also 4 bar , I don’t understand the terminology but also to let you know I will be putting a carburettor on and if you would know of a longer duration cam for street use I have a c4 transmission to go
Im using 98RON here in Australia...350 sbc 10.5 compeession approx 500hp engine on dyno...I locked the timing out because it really likes it at 30° total...with the cam it has it wouldn't idle good under 16- 18° initial...i can double check that...and MSDs largest bushing is 18°....so my initial and mechanical was always 34-36 which i thought was the go to number. I have aluminum twisted wedge heads too.....now im at 30° and im keen to put it on the dyno to see the difference in power it makes compares to the higher timing numbers i was kinda forced to use....after seeing your video i was like wow until now i thought i was detuning it having it at 30 but it feels stronger than before.....my mates 383 made max power at 28 total locked out also.
Your engine really needs a vacuum advance distributor. It would take some stress off the starter and make it easier to crank with a lower current draw on the battery, and as soon as the engine builds manifold vacuum it would clean up the idle nicely. Your 30° total would be 12° initial with an 18° bushing and it would idle with 20-26° depending on the adjustment of the vacuum advance. At WOT the manifold vacuum advance goes away and you run strictly mechanical so you’re back to the optimal 30° under hard acceleration. What you’d see is an improvement in efficiency and drivability at part throttle and much easier starting, especially when the engine is up to temp.
@@TheGT350Garage Hi and thanks for the reply...actually it starts fine at any temps..has an aftermarket starter of some kind...but no kicking back or anything like that. Im also using an 85551 pro billet distributor that cannot accept a vacuum advance canister.
Good video I have a big block chevy I have a 12.5 to one .I have a lock put Dist.and my timing is at 36 .iam going to try to get to 12.3 to compression ratio .Can I run 100 octane on that
You can run 100, but may not need it. It also depends on how you get to 12.3 or 12.5 with a BBC, open chambers and huge domes will need more timing than closed chambers with quench and small or no dome at all. The closed chamber is definitely the better way to go, it will have a faster chamber, require less timing, and actually work better with less octane required.
what would be a good compression ratio for a 600 to 650 hp SBC 383 and cam profile on pump gas? looking at using AFR heads 220 or 227 cc and a holley super sniper and haing it controll the ignition. any thoughts?
EFI changes the game, it makes it much easier to hit the target air-fuel ratios. A typical 383 is a challenging combination, the rod/stroke ratio with a 5.7 rod is just 1.52, so it doesn’t have as much piston dwell time, that means it will need a little more ignition timing than a longer rod combo. Air fuel still needs to target the .86-.88 Lambda range. As far as compression, I wouldn’t hesitate to build a 12:1 or even 12.5:1 383. Do your research on the heads, it’s hard to go too big for what you’re asking, and don’t be afraid to leave the 23° heads for a 15° or something shallower. A little fun math to calc a 650hp combo: 650hp is about 65lb/minute of air flow. 1lb of air is 13.33cu/ft. (65*13.33=866.5cfm) 866.5cfm * 1728 = 1,497,312cu-in/min /383cid * 2 (crank revolutions) =7818rpm at 100% VE. If you exceed 100% VE you can make the power at a lower rpm, but we’re talking a couple hundred rpm sooner, maybe 7200-7500rpm depending on how detail oriented the build is. You’ll need BIG heads, you’ll need a BIG cam. I’d look into heads flowing in the 300cfm range at .400-.500” lift and cracking 350cfm at .700-.750 valve lift. Check out Eric Weingartner’s TH-cam channel for ideas on heads. Cam will need to be in the 255-265° range @.050” and near .700 lift to hit your goal. Of course the specific grind specs will make or break the build. Also, there are two ways to get 383” out of an SBC, the easy way, 4.030 bore and 3.75” stroke, or the better way 4.185 bore, 3.48” stroke. The bigger the bore, the better the heads will flow, the shorter 3.48” stroke with a 6.125 rod makes rod/stroke ratio a much more desirable 1.76:1 gaining back some of the torque lost to the shorter stroke. Have fun:
I'm about to attempt 13.5:1 static with a GTX55 Nissan VK56 engine on ethanol. It has all the supporting mods and E85, we'll start with 15psi and creep north from there, engine revs to 9500rpm. Thanks for the video, wish me luck haha
Cylinder pressure is cylinder pressure. As long as you don’t have unrealistic expectations about your timing numbers or Lambda/Air-Fuel Ratios I don’t see a problem here. At 13.5:1 static and 15psi you’re at 27:1, this is equivalent to 9:1 static with. 30psi. The difference is you’re going to create the same cylinder pressure with less air and fuel, which means it will be more efficient than the 9:1 combo would be. You’ll use less total air and fuel to make the same power in the same engine with more compression and less boost pressure. I’ve done this nearly 20 years ago with 2.0L Fords, not quite to this extent, but I transitioned from 8:1 with 15psi (286hp) to 10.5:1 with 12psi (338hp) in the same engine. To make over 50hp more from the higher compression combination was astonishing at the time, and clearly demonstrated that combustion efficiency was more important than airflow. I saw lower EGTs and was able to run slightly more timing to achieve the final output, and in both cases Lambda was about 0.78 at peak torque and 0.82 at peak power. Seriously, best of luck.
@TheGT350Garage thanks for your response! I had the same outlook with cylinder pressure having stuffed 60psi into my 2.2 4 banger for many years on 9.1, low timing figures around peak torque is always the way we tuned to make them live, but yes we'll be super cautious and depending on how it goes drop it a little if we need to, but comp is new to me and I'm excited to feel it! In fact, given this has such high comp, we will tune it like it's a stock bottom end 4 cylinder and let the cubes do the work.
Read your spark plugs if you don't have any of the expensive tuning equipment. As for timing it doesn't really matter as far as an arbitrary number if the burn rate is faster less timing my set up likes more initial timing 14* and less overall 19* to 20* for a total of 34 to 36 at full advance. Read your plugs you can see clearly if your lean. If so set up your jetting one or two say from 68 to 70 primary and depending on if your running a 4150 carb with power valve secondary or not adjust jetting or PV.
Well id like to think i know a little myself. And what i know is ( i havent watched yet ) its better to run lower compression and more ignition timing. Now sure there a big amount of work that can help things work right like combustion chamber shape, cuts on the vavles port velocity cam timing, all play into helping things work better as in cr.vs octane. Look at the new (say 2016 and up) super bikes. They are 11- 1.minimum some are 12 so it can be done. But the biggest help in that area is digital efi more over a stand alone system that will alow you to make fuel ratio adjustment every 250 rpm as to where the factory ecu's allow a fuel adjustement at every 750 rpm and onviously ignition timing as well so that alone will alow you to run with a good chamber 11-1 the LT1 Chevy sb with water to the head first will run 11.7 to 1. with pump gas. But im always up.for learning more so lets see what the man says .
The key thing to understand here is that timing itself is not what makes power, and more octane is not what makes power. Releasing the full energy content of the air-fuel charge and converting it into pressure is the goal, that’s more a matter of understanding the combustion cycle and the behavior of the air-fuel charge in the specific engine you’re working with. The timing still needs to be “correct” for the cycle, and the air-fuel charge needs to be the correct ratio to produce the energy required to reach a specific power output. Changing the temperature of the combustion chamber will allow more compression which will increase the temperature of the charge making it more reactive before you reach the point of auto ignition or allow more timing advance at the same compression ratio to increase pressure in the cylinder before causing spontaneous combustion elsewhere in the chamber which collides with the intentional combustion causing detonation. High compression has been used more and more in recent years but even with bikes, forms of variable valve timing are being used to manipulate the cylinder pressure. I’ll be sharing more information about high compression and camshaft timing soon.
In response to the 1st potion of your response. That is exactly what I said. To be more clear the design of the combustion chamber has more effect that anything when it comes to how much octane is needed..Also toluene does not increase octane. It was invented by the Renault F1 team back in the early 80's when they (F1 teams) were restricted to a 100mm inlet on the turbo and used a spec gas. Which I think was the unocal race gas. So by 83-84 they were making close to 1700hp.in Q trim and race tune at about 1450 - 1500hp from a 1.5 ltr. 4 cyl.. compression with 3 bar of boost static compression was 36:1 and higher toluene slowed the burn speed down and almost vanished spark knock forever Vp fuel C16 is 28% toluene. The F1 teams were restricted to 22% toluene is actually used as chemical flame retardant. Fireman suits.
@forcedinduction5245 you aren’t conveying cohesive thoughts in your comments, and a large part of what you’ve posted in this most recent comment is completely untrue. Toluene has been around for over 150 years, it was t “invented” by Renault. It’s not a magic elixir that cures all detonation even in high concentrations. 3-bar (4 atmospheres, or 45psi) resulting in a 36:1 static compression would mean a base compression of 9:1, but F1 (and Group B Rally Cars) we’re running in excess of 60psi. Of course combustion efficiency is key, but none of this has a damn thing to do with the purpose of this video.
I have my 302 stroker at 42 degrees. 10.5:1 compression, pump gas, car is light weight. When I took it back to 36 degrees, I lost a 1/10th in the 1/4m. Seems weird, your thoughts?
In my experience, you’re either dealing with an incorrect pointer and balancer relationship, or you are using a timing light that is misinterpreting your ignition timing. A lot (most) digital timing lights can’t handle multi-spark CD ignition outputs. The multi-spark output skews the timing light signal making it seem like the engine is tolerating more timing than it is actually operating at. I’ve been using the Pertronix Digital HP ignition more the past few years and with great success, and one of the key features I use on it is the ability to disable multi-spark for timing purposes. Now, it’s also possible your engine is not actually 10.5:1 and your cam may be bleeding off so much compression that you effectively have far less cylinder pressure than you think. Running a compression test correctly will tell you the engine’s pumping performance, and identify a cylinder pressure issue. Using an analog (old school) timing light can help you identify an issue from your ignition system. And finally, putting a piston stop in the no. 1 cylinder can help you ensure the timing pointer is truly reading TDC at TDC. The final caveat is that some cylinder heads (you don’t state what you’re using) have truly terrible combustion chambers, meaning they are inefficient and cause a “slower” burn rate leading to a need for more ignition timing. This is a common problem for D shaped wedge type chambers like FE Fords, but some Windsor heads (OE and Aftermarket) are affected by this chamber shape issue.
@@TheGT350Garage The pointer was checked. Old style ported Trick Flow heads. Compression test, with a cheap tester is about 185 and even. Cam is 231/239 @.050 and 110 LSA. And I just use a basic timing light. Ignition is just a Fast brand ready to run deal. No multi spark. Thnx
Ok, if you’re using old school High Ports, especially aluminum, then yes, you’re in the ball park, at 42°. Those heads have a rather slow chamber. I would caution you to be careful with the rate of advance, meaning don’t run an overly aggressive curve, bring in total at 2800-3200rpm, and use vacuum advance to improve idle and cruise efficiency and lower operating temps. Twisted Wedge heads, be it a 15°/17° 170/185/205 head, a Twisted Wedge R, or the newer 11R series, have a much more efficient chamber and for your cylinder pressure on a 347 they would want 34-36° max, all in at 2600-3000. It would be worth a couple hours on a dyno to set up the air fuel ratio and then optimize the ignition timing on the car at several points in the rpm band to find the ideal shape for the ignition timing curve your combination truly wants or needs.
I bumped a 5.2 magnum from 8.8:1 to 9.26:1...its now developed an appetite for 90 octane. You must meet the engines octane requirements..no if ands or buts..detonation will rapidly deconstruct your engine.
If you use the same ignition timing and air fuel ratio at 8.8 and 9.3 you’ll need about 1-2 additional octane points, or as you’ve observed an increase from 87-88 to 89-90. Your assessment that the engine requires the addition of more octane is because you have ignored both the air fuel ratio and the ignition timing in the OE fuel injection. Optimize the air fuel ratio and you’ll find the engine can return to the original octane rating by running at .84-.86 Lambda and you’ll also be within 1° of the original ignition timing. Making the same if not more power than you are on 90 octane with the lousy factory fuel and spark mapping.
@TheGT350Garage Not having access to high end tuning equipment leaves me kinda going old school. With success I'm happy to report..using live data to monitor o2 sensors and fuel trim led me to a lean condition. Plug reading confirms this..a small vacuum leak was repaired and colder 3923 plugs installed along with low ohm wires has me burning the rot gut again 😆
“High End” tuning equipment is not really necessary. You can’t rely on fuel trim data from a narrow range oxygen sensor though. They can only detect Lambda (Stoichiometry). If the sensor’s cut point for stoichiometry is .450v (450mv) any time you’re below that you’re lean and any time you’re above that you’re rich, but in either case you have absolutely no way to know how lean or how rich you actually are. If your ECM was originally built with the assumption that the stoichiometric ratio of the fuel was 14.7, the sensor will perpetually give a lean signal to the ECM because modern ethanol blended fuel hovers in the 14.1-14.2 range. So your fuel trims will always show roughly +5%, or 5% lean, and if it’s an older (pre-2005 ecm it’s a challenge to interpret this). This is where you do need a wideband oxygen sensor and with kits in the $200 range now (they were $3000+ when I started tuning) it’s no longer a high end tool. If you adjust the fuel pressure up or use a slightly larger injector (assuming it’s speed density and not mass air flow) you can get back to the correct air fuel ratio without needing to reprogram the ECM. Whatever you do, you need to stop thinking it’s a fuel quality issue and realize it’s actually a simple adjustment to a slightly different stoichiometric ratio that’s needed.
So do you run high dome pistons with a tighter squish in your high compression engines? Also does it help to add a little nitro? Thanks for the information 👍
I prefer to run a flat top with a small combustion chamber, but in the case of the 289 I’m building for the Shelby, there is a slight dome, about 0.060” on the piston. I’ve had the block machined to create a “zero” deck, meaning the pistons are flush with the deck and the domes in this case are above the deck. For most 289/302 builds this requires using the 8.190” blueprint specification from the 69-70 Boss 302 Trans Am engines. Nitro(methane) is a volatile self oxygenated fuel and would have no place in a street engine. Nitrous oxide (another way of oxygenating you’d mixture m) on the other hand would love this combination and set up correctly you could add quite a lot to this type of combination, but laughing gas is like making wishes with the genie in the bottle, the first few times is usually fine, but eventually you get screwed over.
I am going to be running my 434sbc 63 nova on 11.04:1 SCR and 10.2:1DCR for the first time this year. It has 225 cranking pressure and probably needs a bigger cam. How worried should i be?
Back the timing off and push the a/f slightly rich, it will run fine. Do you need more cam? Yes, absolutely. At sea level the “ideal compression test pressure” from 11.04:1 is 227.2psi, ((14.7*11.04)*1.4) so you’re right there. Retarding the cam or adding more duration, both resulting in a later intake valve closing event, will allow some reversion at lower speeds to reduce the effective compression ratio, and producing less cylinder pressure. Ideally, 190-210psi is a manageable range to be in, so you’re not far off. If your cam is installed 4° advanced, simply moving the cam to 4° retarded would get you closer if not spot on in the ideal range, otherwise you’ll need a cam with 12-16° more duration @.050” to get the closing event optimized. Retarding the cam improves the idle, evens out torque production across the range, and shifts the power curve higher about 100-150rpm for every 2° you retard the cam.
real life useable information. Now what crank,pistons,and connecting rods are you going to use to get your 12.5:1. what will your qwench number be? head gasket thickness?
Getting 12.5:1 from a 289 is a challenge without using a big dome. My heads are TFS Twisted Wedge and they are being milled to bring the chambers down from 61cc to 46cc, a 2cc dome, the block is decked to 8.190” and I’m running 12.29:1. It’s not a combination for the faint of heart or those who don’t give tremendous attention to detail.
No. Because I’m moving the port up the face of the head and away from the deck, the majority of the port alignment is addressed that way. I was able to leave the manifold it’s original width, elongating the bolt holes slightly inward for bolt alignment. Doing it this way also means no machining at the end rails on the valley. But, it’s A LOT of work and time to get everything matched up. Everything is done on the gasket faces, but even the water ports had to be addressed to prevent water leaks.
This is a ton of information, great video my question is where I’m located the octane rating is not provided how can I determine the octane cuz I want to run 12:1 compression
The fun thing about the internet is that with some effort you can find out a lot about things you didn’t think you could learn about. I would suggest talking to your local fuel stations to find out what refineries their fuel comes from. Chances are it is coming from a refinery that produces fuel for a known brand. At that point you can get an idea of what they are selling as regular or premium fuel. Depending on your engine, it may simply be a matter of build the engine, target a Lambda value of about 0.85 (regardless of the fuel), and then do some testing to find the timing threshold for the engine. At the extreme of things, I’ve run 13:1 and used 87 octane in a DOHC 4-cylinder and it worked quite well, making over 100hp per liter measuring at the drive wheels.
?.. so i am tuning a 91 mustang eft using wide ban .. 357 . Now all guys say set ur target is 14.7 so whats ur opinion running 93 pump gas which all pump gas in 10% ethanol
If you can change the stoich point or reference Lambda in your wideband to 14.1 and tune in Lambda for - target of .86-.88 Lambda you’ll be on the money. With pump gas your target under load results in a 12.1-12.4 A/F on E10 premium. You can run a little leaner past peak torque but timing will be more and more critical as you pass .90 Lambda or 12.7:1. Timing should decrease about 1-2° per 1000rpm above peak torque, which means you’ll be 3-4° less than what makes peak torque at peak horsepower. If peak torque comes from 33-34°, peak horsepower will come from 30-32° in a typical SBF running 9:1 to 10:1 compression with a decent cam and aluminum heads.
Great video and makes perfect sense. I've often thought that setting timing crazy is going to make a bomb. I'd be curious to see what compression ratios are of 9.1 under 20 pounds of boost.
So atmospheres pressure is 14.7psi at sea level. If you add 20psi, it’s 34.95psi acting n the engine. That’s 2.35 atmospheres, so you multiply the static compression ratio by the atmospheres meaning 9.1 Compression is the equivalent to about 21.4:1 at 20psi manifold pressure. That’s a big number but it will still run on pump gas with EFI.
I have a 302 with flat top pistons and .035 quench, 58cc chamber. I used a compression calculator that said 9.9:1. dynamic, with stock GT cam, said 7.4 . I run 87 regular and cannot hardly make it ping....but the car weighs 2850 and has a 3.25 gear. So, would advancing the cam give more dynamic compression like the calculator says? My heads are already milled .040 to get here, so there is nothing left to increase in the static dept.
Dynamic compression is not the end-all be-all answer to detonation, octane needs or engine tuning. It has very little to do with it actually. At 9.9:1 your engine should have a cranking compression test value in the 175-185psi range, especially if by stock GT cam you mean a 5.0L HO roller cam. Advancing the cam from the stock 115° ICL to say 107° ICL will alter the power curve but have minimal effect on the cranking compression, it might go up 5-10psi at most. The problem is it doesn’t change the overlap and therefore doesn’t benefit the engine much. If you study camshaft events thoroughly enough you’ll be able to make an argument for the importance of EVERY individual cam timing aspect, EVO, ECL, IVO, LSA / Overlap, EVC, ICL, and IVC. And each one has important roles, advantages, disadvantages, and reasons why you will or won’t do a particular thing with them, or you’ll fight to get a particular number for one or more of them. Dynamic compression focuses on IVC like it’s the secret to utilizing high compression, BUT I can argue that LSA and Overlap have a greater effect on compression than when the intake valve closes, that IVC is perhaps even irrelevant in terms of “compression”. My suggestion is a different camshaft will produce better results than altering the installed relationship to the crankshaft. If it’s a roller motor, going from a stock HO cam to an old school X303 installed “way out” at 113° ICL would net solid gains and retain you 87 octane compatibility. That is, if you have the room.
@@TheGT350Garage You make an excellent point in that closing the intake valve sooner at the expense of moving overlap events away from TDC may not increase captured air volume at all....if I understand you correctly. I have been studying this for a couple years, but lack real experience. The engine referenced above was done with a budget of 1200 bucks, for the purpose trying to understand the process well enough that if I ever put real money into it, I would spend it correctly. Actually, I notched the pistons and checked the clearance before final assembly, and had .100 on the exhaust and intake. I dont know if the piston liked what I did to them, but I have put 1500 miles on it and run it hard at least once everytime I drive it. I will leave it alone for now.....eventually I will pull the heads and grind a little more on them and give the intake valves a 30* cut back. lol...my cylinder head tech dept. got better since. I will keep my eyes open for a x303. Thanks for your reply.
I've got a 67 fastback I run a 289 with race tech dome Pistons and 58cc aluminum heads, mechanical cam. It runs good pulls hard to 7500 rpm. I can tell you this 91 pump gas 10% alcohol sucks In the summer at 5000ft it boils in the carb. When I mix it 50% and 40% pure gas and then 10% VP leaded race fuel and it makes all the difference in the world in drivability.
Altitude lowers the pressure which in turn lowers the boiling point of the ethanol. It’s a challenge. Have you considered using a heat barrier gasket like an Edelbrock 9265 or 9266. They are based on the gaskets used to separate the heat of the EGR spacer from the carburetor on emissions engines and do a good job of reducing carb temps. Another possibility is to install a return line and fuel pressure regulator (similar to early EFI systems) and put a cooler in the circuit to reduce the temperature of the fuel. I’m at 4500ft and these are things I’ve done in the past for operation at altitude.
@@TheGT350Garage All good Ideas what I have done is run a spacer between intake and carb also have a cobra jet scoop but it gets over 100* here and a black hood doesn't help even with heat extractors. 100% gas works the best ,for me. Also Aluminum heads allow for higher compression I run my 289 hard close ratio Top loader Detroit locker and 4:11 it's got just enough gear to be quick, smoke a lot of homies. I built the this pretty much like a 65 gt 350 all suspension mods hotter 289 but it's been fun for 41 years I've had it since I was 14yrs old.
Sounds like a really fun combination. The key to stopping the ethanol from boiling out of the fuel will be pressure and temperature control, which are hard to do in a fuel bowl. Short of keeping the fuel under pressure using fuel injection all you can do is seek out clear gas (ethanol free). We have 91 octane ethanol free at a couple locations here in northern Utah.
I the weekends i Work in a scooter shop.when customers put 10 percent ethanol mixture in these 4 stroke scooters. The combustion chamber and valves will cake up and will not close 100 percent and compressie willen drop.without the ethanol mixture there is no problem on tesame kilometers
I agree with softening but not “slowing” the chamber. I’ve applied the principles of the “soft head” and “groove theory” in building engines over the past 20+ years, and both when applied correctly work very well, but both require a rather tight quench area and a small combustion chamber to be most effective. For the average enthusiast, simply detailing the combustion chambers to remove any sharp edges is an important and easy step to pull the most out of the chamber, a basic softening technique. Even CNC machined heads benefit from a light touch with some abrasive, be it hand finishing with 400 grit paper, or like I do with Scotch Brite pad in a mandrel on a die grinder.
You shouldn’t need race gas at 11:1 compression. Before I can comment on timing setup, I need more information about the engine combination. Head info: Ported? Open or closed chambers? Piston info: Flat top or dome? Cam info: Int/Exh Adv. & .050” duration? Lift? Installed Lobe Centerline? Lobe separation angle? Carb? Intake? Headers? Exhaust? Cranking Compression? If you can fill in all or most of those blanks, I’m happy to give you an idea of what’s going on and how to approach it.
@@TheGT350Garage....has knuckle top pistons,stock iron heads,valve sizes stock, w/exhaust opened to 350 sizing, and intake hydr cam specs unknown.Has 1.5" ceramic headers,480 QFT carb, pro billet dist....roller rockers 1.5 ratio,6 qt oil pan....now using 12 deg initial and 28 total timing with approx98 octane mix....though I am diluting out the 110 race gas to arrive at trying only 93 octane as I tighten up the total timing to avoid pinging
You’re missing the context that compared to engines prior to WWII, an 8:1 compression ratio was relatively high compression at the time, wether it was considered high compression or not in period wasn’t the point, it was a substantial increase from the previous generation of engines. The development of high octane fuels after WWII allowed us to build what we consider truly high compression ratios of 10.0:1 and greater like the Chevelle SS you’re referring to. And in modern context, 10.0-12.5 compression ratios are not really “high compression” anymore, they’re quite common actually. I have a new video coming where I’ll get very specific about compression and cylinder pressure.
@blackericdenice directly from the transcript: “By modern standards, high compression is any engine with a static compression ratio over 10:1, but prior to the Muscle Car era (from 1964-1974), 8:1 compression was considered high compression.” “Prior to” not during the Muscle Car Era of ‘64-72. I appreciate your comment.
You're going to have to correct something you said high compression ratios were from 66 to 1970 as much as 12 to 1 compression, then from 71 to 74 they were considered smog motors and lowered the compression to 10 2 to 1
‘72 was the year compression ratios dropped, not ‘71. There were still a few hold outs that got through into ‘73, not many, but ‘71 was still a good year for factory muscle cars.
Fools and their money are easily parted. E85 is a joke, and the joke is on people like yourself who think it’s better than pump 91-93. The garbage they call E85 from the pump is wildly inconsistent and has to be tested tank load to tank load due to wild variations in ethanol content. Canned E85 is expensive enough you may as well run proper racing fuel. And if you’re only running WOT, you probably have a 12-15 second attention span so I doubt you grasped the concepts presented in this video.
You referenced specific heat while calculating compression and dynamic compression at 1.4. What is the specific heat of the compound you are refering to? just googled gasoline and its 2.2+/- so is it the combination of gasoline and air at stoic? Thanks for bringing up lambda because its really the best way to look at fuel use and need of every individual engine. Two exact cars with exact builds will vary (maybe only slightly) but that slight difference can show discernable characteristics that each engine has (quote unquote identical builds), ergo the differences in necessary adjustments for optimal desired function.
I’m in the middle of a 6.4 hemi (2016 scatpack) build . Building a 426 stroker 9.51:1 static for turbo boost. I’m talking 3650 ish street car and try to run it on pumpgas too.. (planning on a second “track “tune . Maybe with a second gastank and bigger pump too) . I’m a the point to choose a cam for this build . Maybe you can shine some light here? What are the limits to run this on 91 or 93 pumpgas ? If I would have 750 hp ish at the crank for the street, will be more than enough.. Thanks from the Netherlands 🇳🇱 Denny
Your power goal puts you in an unusual situation. A 426” 3rd Gen Hemi? Build it N/A. Let it make power. Push the compression up to 12:1 and get a cam in there that will unleash the full potential of the engine. It should be able to push 650+hp at that displacement from the parts available for that engine, then put some gear in it and turn it loose. The simplicity of a big displacement N/A build is hard to beat. The turbo route is fine, but you’re adding complication and weight, generating and retaining more heat, and for little more than an extra 100hp over a legit NA build. You ultimately have to sacrifice efficiency and power to be in the 750hp range and you’ll have a challenge getting a single turbo to work well at relatively low boost (6-8psi for your power goals on that engine), smaller twins would perform better but add further complication. Cam selection will be critical (and on the small and conservative side) because it has to balance cylinder pressure with exhaust drive pressure to get the turbo to respond, and not cap the power potential simultaneously, or produce too much cylinder pressure and create a fuel octane sensitive monster. My advice would be dial back the power goal slightly and build a proper 650+hp N/A combination, or up the power goal to 900-1000hp and build a proper turbo engine, which will ultimately cost little more than the 750hp you want.
Sorry for the late response…., just this morning I noticed the push message . I know the turbo route isn’t the easy way, but it’s on my mind for a long time. It will be something different, not many are around back here, I’ve never seen one. I could go up in power goal, let’s say 900at the crank. But what gas would I need ? ( we don’t have E85 at the pump) And how about dynamic compression ratio and effective compression ratio in relation to the gas I would need to run ? Because you’re right.., the last thing I want to do is turn this build into a fuel octane sensitive monster…
@@hemi-denny set the compression ratio and n the engine at 9:1 to 10:1, and target 500-550hp, build it with parts hood for 1000hp. 7-8psi will net you around 800hp, 14-15psi will put you at close to 1000. All of that is attainable on AKI 91-93 octane, 95-98 RON. You’ll just need to be careful with the air fuel ratio (target 11.2-11.5:1) and bring the timing in gradually, you’ll need to install an EGT on each bank and watch your temps to make sure you advance the timing enough to keep the the exhaust temps from damaging exhaust valves or the turbine side of the turbocharger(s). With the slower nature of a Hemi combustion chamber and the compression and plboost range you’re targeting, I suspect you’ll need 23-26° of timing.
@@TheGT350Garage For some reason it takes 10 days before I get your reply…. ,so again sorry for the late response. I appreciate your help and information a LOT !! The plan I have in mind is to put a single turbo underneath the car at the spot where the muffler use to sit( in front of the rear axle) . And at the other side a water cooled Intercooler (no mufflers at all in mind). I have TTI ceramic coated 2” headers and plan on heatwrap the exhaust and Y pipe underneath the car . How about if I stick to the stock (smaller) Scatpack cam ? For better spool ? Stock (Scatpack) cam 215/221@.50 and can be advanced 14 degrees, from what I have red. Really looking forward to your opinion about this.. Thanks again
@@TheGT350Garage I forgot to mention the LSA of the cam ( 121 , again from what I red on a challenger forum) Probably some additional info about the short block/stroker kit will help too. Bore is : 4.10” Stroke : 4,050” Rod length: 6,125” C.R. : 9:51 All forged internals , hope this helps too to get a better picture of what I’m trying to do.
Doesnt tell me "how to tune", just tells me the characteristics of fuel and engine. Great info, that I knew, but, I want an hour of my life back!!!
What are you expecting, someone to come hold your hand while you change jets?
@@TheGT350Garage - Looking past the obvious, I would at least like to know what tool to pick up and what to adjust, and for what outcome I am looking for.
I have an idea what I am looking for, but I came here to see if you had something special to tell me, that I dont know.
Since you didnt mention anything about what tools to use, what to adjust and or tips n tricks, cant say I know anything NOW I dont already know.
Was all that, just to say "set your a/f to 14:1 on non ethanol gas and pull back timing? If so, I will give you 10 minutes of credit while still demanding my 40 minutes of life back!
A very informative video. Kinda made me look at things a little different. It does make sense considering that how you tune a forced induction type engine i would imagine. I have been trying to figure out how to do this. I tried fiddling with the dynamic cr calculators. But they are all over the place. Would you have any examples in videos or upcoming videos? I have an 11:1 cr aluminum headed 383 chevy. And I have been trying to figure out if I could run a 224/224 110 icl/ 114lsa cam. And if I could install it on a 106icl. Running 91-93 pump gas.
@JoshF89 I do have a video in the works that will really help you. As for your cam selection at your compression ratio, it’s quite small and will make far more cylinder pressure than you want. Duration will need to be 12-18° more than you have and the ICL/LSA numbers I use on high compression builds for street use are drastically different than what you’re describing. If you’d like to discuss cam selection further, please shoot me an email to thegt350garage@gmail.com and we can go from there.
@@mistersniffer6838ok ok in
Great video, and some tuning tech genius that I suggest every enthusiast takes a moment to archive! I was running a poncho on evil "pump gas" with a 13:1 compression 400 Tri-power in a 4200lb car back in the early 90's. A few interesting projects since then as well. Everything you discussed is spot on with the tuning conditions utilized in my Pontiac builds. The one topic you didn't touch on, but was anticipating, was your knowledge of how spark plug design, voltages, and heat range selections tie into (affect) the flame propagation cycle, timing, and mitigating pre-ignition.
My take on plugs is different from most. I’m not a fan of big gaps, .025-.035” depending on the engine and ignition system being used. I like Autolite Copper and Autolite Racing plugs for most engines, which inevitably leads to an argument from someone who thinks NGK TR6 Iridium’s are gods gift to engines. I’m not a fan of “gimmick” plugs, it doesn’t need multiple ground straps, V shapes, Y shapes, U shapes, or any special metals. I don’t run platinum or iridium plugs because of heat range issues and inconsistencies I’ve had with them. And I’m not a fan of fine-wire center electrodes, I’ve seen many go “missing”. Also, plugs are cheap, and relatively easy to service, if you want longevity from spark plugs, keep the car stock. Heat range only needs to be hot enough to keep the plug from fowling at idle, gap needs to deliver a spark that’s strong and consistent. This is an area where people tend to overthink things and end up spending money they don’t need to. Copper plugs will typically last 10-15k in a reasonably maintained street application, and they should be checked every oil change or seasonally. Coppers are also cheap enough to keep a set stashed in the car if it’s a driver and can be changed on the road if you have an issue.
@@TheGT350Garage My thoughts exactly
Just leaving some bookmarks that I’ll probably come back to
26:09 dynamic compression
36:01 air fuel mixtures
37:24 lambda
41:03 ignition timing
Thank you …timing and AFR all I wanted
@mikemaguire5507 if you don’t take the time to understand the difference between modern fuel and fuel of the past, you’re probably not going to get the results you want.
Great video, I agree. I ran a 11:1 289 with a 650 dblpumper & 32/34 deg.on any premium pump fuel for years in the mid 70s. Never had a problem. Had to use 2:79 gear once(built a 9"w/Detroit Locker 4:10) and got 28 mph hyw.
You could only run 28 mph on the highway? Damn, should have geared it differently, that's slow as f***!! My car would whip dat ass! Talk about getting gapped!! ROFLMFAO!!
He was clearly implying 28mpg not 28mph.
I've been building engines for street and strip since 1970. Yes, I'm old. 71. I agree with what you're saying. I still have a small hot rod shop in Texas and am still playing with cars.
My daily driver is a 1962 Falcon , powered by a modified 302 .12.5 compression, 351 Edelbrock heads, Offenhuser Tunnel Ram with Holley 550cfm Tunnel Ram carburetors. Top loader 3 55 posi. 9 inch . 2400 lbs car.
Iv been running 92 oct for the years iv been driving it. Timing full advanced at 28 degrees.
When I'm racing it I use 110 oct. advance timing through my MSD Ignition.
Anyway I just run across your channel. Thanks enjoyed the presentation.
You have a fun setup, it’s likely you’re running a decently large camshaft. The point of the video is to help people understand what’s possible, it’s rare to find someone like you who will admit to doing it successfully.
One of the most fascinating things that impress me in the modern internal combustion world is the 5.3 liter V8 with cylinder deactivation in my 2015 GMC Sierra 1500 pickup. It delivers 355 net hp on an 11 to 1 compression ratio on 87 octane gas! It makes great power and I can hypermile in it by running a reduced fuel load (weight) a lightweight tonneau cover for the bed (reduced turbulent drag) and higher tire pressures (35 psi cold). On cruise control on the rolling highway at 55 mph I have repeatedly achieved 30 plus mpg with an all-time high of 32. I'm not flying along like everybody else at 80mph, but the point is that you can achieve great mpg on a 5,000 half ton pickup if you want to.
I can imagine even better results on flat terrain.
Without the benefit of a knock sensor to detect the threshold of too much spark advance, it’s a bit risky to run 87 octane above about 10.5:1 compression. But with a knock sensor, I’ve run 87 octane win fuel injected engines as high as 13:1 with good results.
.....You my friend are blessed with a high intellect.................far above average hot rodders..................................I'm 71........Been around studies of engine building and Drag Racing since 1965..........I'll have to watch this video a few times and record on paper what I may forget......Thanks.......
There is more on this subject in the works.
Thanks, very informative, what doe you think of octane boost products?
@Fordcertian if you tune to the fuel, you don’t need to change the fuel. Octane boosters are inconsistent and essentially a bandaid fix for incorrect ignition timing. They do nothing to improve the energy content of the fuel or the conversion of the energy in the fuel.
Brother, you are a Godsend!!!.....I have had many sleepless nights of the last few days contemplating how to set up my new 496 Chrysler...at 3400 ft in Hesperia California my calculation shows I need at least 10.6 static compression BUT I like to go down the hill to Riverside to see friends where it's 500 to 800 ft...yes, I have issues, but after this, I'm more confident I can make this work with a little attention!
I’m originally from SoCal and lived there until 2017. If you run a vacuum secondary carburetor it senses demand and opens less at higher elevations. You basically just tune the carb as if the tune was for “elevation” on the primary side, and at 3500ft you’ll want an AF ratio of 12.7-12.9:1 at WOT and 13.3-13.5 at cruise. Easy to do with a Holley 4150 Vacuum Secondary, you’d just need the big 870cfm model. For the lower elevation tuning, you’ll leave the primary side of the carb alone and increase the jet size 4-6 numbers so that your AF ratio is about 12.2-12.5 at WOT and so you cruise in the 13.0-13.2 range down in the IE. The numbers sound rich, but the fuel in CA is heavily oxygenated and burns like a leaner mixture with its lower stoichiometric air-fuel ratio of 14.0:1-14.1:1. I used to live in the AV and I’ve run cars at LACR, Famoso, and Irwindale, all using the same tune, and driven them at 4000+ft elevation over the Crest, the Grapevine or Tehachapi to get to the track.
If you’re still building the engine, the big Mopars like compression, I wouldn’t hesitate to go 11-11.5:1, then run a bit more cam and let the cam specs help you arrive at a dynamic compression in the 9.0-9.5:1 range. If you use the information I provided about timing, and I’m doing a follow up video to give even more insight into building the timing curve, you’ll be able to dial it in so you don’t have drivability or temperature issues.
@@TheGT350Garage thanks for the reply, it means alot to me right now, I am currently reconfiguring this engine, and yes, it appears that 9.0 to 9.5 is what seems right...but the common "thought" is saying I need to be at 8.5 to be "safe"....I actually have flat tops in it now that are .025 down in the hole..I'm showing 11.3 static, but they are sitting. 025 in the hole right now.. I was thinking about getting new pistons with a 12cc dish to put me at 10.6 or a true 11.1 if I take a bit more off the deck..I think with the quench issue, this would be best.(but I'd be interested in your opinion) I'm using the Trickflow heads with a 78cc chamber so I think this setup would be good.ive see 3 builds with these heads, and 32 to 34 degrees totalis what they seem to like best, this falls in line with your timing strategy from what I can decern..I'll probably go with a 250 @ 50 cam like you suggest...I already have a Ultra 850 HP carb, which may be a bit counter productive, but I will probably stick with it seenings that my car is a 4 speed....I'll be looking forward to your next video!
The “conventional thinking” of the past 50 years still holds a lot of guys back, and combined with a very poor understanding of modern fuel, it has lead to many an argument surrounding the operation of high compression engines on pump fuels.
On my 289 Ford, the static compression is going to be 12.0:1. The intake valve closes at 70°ABDC and that comes in at 9.09:1 Dynamic compression. In reality it’s higher than that due to cylinder filling characteristics and other factors, much as I describe in the video.
If you want to provide more cam info we can discuss the details specific to your engine. I will say a flat top with quench is better than a generic dish at “zero deck”. If you really wanted to fine tune the combination for a specific compression ratio, you’d want the piston at zero deck and an inverted dome (a dish that mirrors the shape of the combustion chamber to limit quench and control the charge better.
Your 850 HP Ultra carb is A LOT of carburetor for street use. Not the CFM rating, that’s fine, it’s the extremely adjustable nature of those carbs that get a lot of guys in trouble. You will need to study what all of the various adjustments are doing and carefully adjust accordingly. It’s going to take some effort to truly understand how capable that carb is and make it work for your needs. I would also suggest splitting the difference from an altitude perspective and tune to the middle, meaning if you live at 3400ft and you’ll occasionally get down to 600ft, tune the car to operate best in the 2000-4000ft area and don’t beat on it at lower elevations with higher air pressure and density without verifying your AF ratio. (Investing in a wideband AF Ratio sensor kit is prudent, and about a $400 expense these days for a dual sensor kit.)
@@TheGT350Garage well, I have a hand full of cams on hand, and I'm ready to pull the trigger tomorrow on pistons if needs be. This is a "back up" engine for my 528 Hemi that I will pass on to my son eventually. I don't want to make it too complex for him, but I don't want a "girley-man" engine either...looking for a maximum effort pump gas engine.
I've got a 243 @ 50, with a closing on intake at 46 This is a trickflow hydraulic roller that is pretty popular, and I've got a solid flat tappet with a 260 @ 50 duration with a closing at 54...I think this is a bit outside of where I want to be, but I've seen it done before in Diamond bar with a similar engine I built 20 yrs ago with the same problem (I gave up on it because it rattled on pump and I was outta $$$ and sanity)...I've got new tappets and pushrods for either setup, and I could see going either way..but for simplicity probably stay hydraulic roller.
Yes, the HP carb is a bit complicated, but that is what attracted me to it. I've had Fuel curve West fully prep it, so it should be a barrel of monkeys at some point.
Depending on how you calculate dynamic compression, by using duration at 0.050” vs 0.006” you get very different numbers. Going back to my combination at 12:1, using the .006” duration gives 9.1:1, but using the 0.050” duration value gives 10.7:1.
Your cam spec is at 0.050”, with 11:1 would give 9.9:1, but using the 0.006” advertised duration it’s 8.3:1. Between .050” and .006” the valve is closing with the piston rising and you will have reversed flow out of the port against the air mass stacking on the back side of the intake valve, so it’s going to be something in between those numbers. You should be fine running around 11:1 with that cam. If you want to fine tune it, you can advance or retard the cam 6-8 degrees from where it’s ground to get the desired result you want.
Great video. It has definitely shot my fuel / octane theories all to hell. I found it extremely informative. Thank you Professor I will have to study much harder.
This was fantastic information! This is much more credible and accurate than most of the information you'll find on this subject in TH-cam land.
Thanks. I’m working towards new content on this subject very soon.
Thank you for this! I'm going to finish this later for sure, as it is easing my worries about my new "10:1" pistons!
Very well narrated ! Had a 10.8 ratio 73 400. .ran best on 89 octane . 425 hp 475 tq. Lost economy with higher octane number
If you had a fairly decent cam in the engine that makes complete sense. It also depends on temperature, elevation, and some other factors. One of my favorite 302/5.0L Ford combinations 20+ years ago was a champion of 87 octane at 9:1 compression. It made 345hp to the wheels, about 415hp at the flywheel, year round in n 87. There was no gain from increasing the octane, it made slightly less power on 91. Back then I was obviously much younger and the guys I was working with were very stuck in the mindset that the fuel of the day was grossly inferior because they had experienced the Muscle Car era and I couldn’t possibly have any idea of what I was doing.
Walter, I just found your channel today and I subscribed right after watching your video on Performance Re-Curve. I have some distributor re-curving I was planning on doing this Spring and I learned a lot from you. Thanks for sharing!
Lots of good info. I will have to watch this multiple times to actually soak it up. Really makes me question if I really can drive my 400 SBC at 12.5:1 on pump fuel with iron heads. With the way you describe thing it really makes me question what I thought I knew but has me wanting to confirm it’s wrong too. U got a new follower that will be sharing your content. Thanks and look forward to learning, understanding more
You do a great job of explaining with rational thinking thru the whole video! Great info!
Second gen camaro. 409 c.i. SBC. 4 speed versus TH400. What compression should i use?
No pwr steering. No pwr brakes. ALthough has AC.
The engine planned is a sleeper stock look engine having a 4.035" bore X 4" stroke. Custom mahLe pistons. Ported and worked Iron eagle heads.
Hydraulic Roller Retro 288* cam with 106* LSA 70* IVC.
And the safety margin during chassis dyno or versus stand dyno only.
This isn’t a straightforward question. The transmission doesn’t determine the compression ratio. There is a lot of missing information, like is that the duration at .050” or the advertised duration (I suspect advertised). The @.050” number is a better gauge of cam size. If the @.050” numbers are in the 225-235° range, compression should be roughly 10-11:1, 235-245° 11-12:1. The 106° LSA is pretty tight and will work fine with higher compression, but there are a lot of factors that go into cam selection, and ultimately cam installation.
The manual transmission won’t care what the combination is, just use a good clutch and gear the rear axle appropriately. A TH400 however will need a converter that matches the engine’s output characteristics if you want it to be successful.
I’m not sure what you are looking for in the way of a safety margin for dyno testing. Be thorough and maximize the average power. Testing isn’t cheap so have a plan, stick to it. Start with 26-28° of ignition timing, get the air fuel ratio dialed in at about .83-.85 Lambda (slightly rich) maximize your ignition timing to find the highest average and peak horsepower and torque. Then fine tune the air fuel ratio into the .86-.88 Lambda range for the hero numbers. On the street I would pull out 2° of timing and jet up 1-2 jet sizes on all four corners of the carb.
@@TheGT350Garage Thanks so much for your reply.
You are a good teacher, you have a great demeanor for teaching. Im a car guy DIY'er and an Engine Parameter Numbers Cruncher. I started back in the early 80's myself doing my own wrenching and noticed back then the wall of nonsence you go thru in the engine building world way back then. Anytime I run into one of "those" ppl who grew up on [all that misinformation] on hot rodding an engine; I always ask one question. That question addresses "Size". When someone uses vague or ambiguous language as Big and Lots of Hp or Lots of Tq - they get asked the question; How do you qualify small, medium, large engine parameters relative to mild, moderate, maximum engine output? Most hot rodding bench racers look at me with blank eyes and give me the shoulder shrug I Dont Know answer. If they respond by asking me to tell them more, then I know I have someone who is teachable. If they respond by arguing their brain washed nonsense, I'll give them a few more questions that will/should allow them to break through the brain washing. If they dont come around - they arent teachable; I dont waste my time I just walk away! Ive even asked my questions to some of the big guys - and dont get an answer. Its interesting how some very knowledgable engine builders have egos that wont allow them to say, "I dont know, tell me more". Your content is just the tip of the Iceberg, but theres only so long you can make your video before it turns into a college semester class room on engine theory. Thx for taking the time, enjoyed the vid
Edit: You actually addresed Dynamic Compression. Most content on Dynamic Pressure is based on the 50's thru 70's tech. If ppl wanna understand Dynamic Compression they should look up The Slider Crank Mechanism and how to chart that data thru 180° of travel (piston travel). It will help them see how much volume remains in the cylinder at each degree of crank rotation. Having watched all of this video now, which I consider Part 1, you should make a Part 2 that moves beyond the basics. Part 2 should focus on Energy Content of the Fuel relative to High Static Compression and Lamda. I just found your Part 2 on this subject; gonna watch that vid now
Thanks! I’ve had a rough year for making content, I hope to be back at it soon, but Part 3 addressing my stance on dynamic compression ratios is about ready to present and Part 4 isn’t far behind. I’ve compiled most of the work I’m presenting in the videos and may self publish it, or lean on some industry friends for a favor to get hooked up with a publisher. It’s always hard to get acceptance whenever you’re presenting ideas that aren’t popular or change longstanding opinions. Great feedback.
@@TheGT350Garage I wasnt going to say anything until you mentioned trying to publish your knowledge to others. Back in the late 90's early 2000's I went thru an adventure on trying to understand the engine. The internet back then wasnt as helpful as it is now. In my few years of research I ended up purchasing 70 books. Back then I wasnt planning on writing a book, I simply wanted to understand the engine. In my early research I decided to put my notes in book form name it, "Dynamic Compression: Never Overcam Your Engine Again". Upon further research I changed the name to, "Understanding The Performance Engine Equation". I held off selling the book as I hadnt any process for the reader on how to properly custom match a Cylinder Head to the Block's Cylinder when upgrading performance: or how to qualify performance in general. I didnt want my book to be incomplete like everone else's book; full of pic's but no useable content. I had to figured out how the relationship changes between the Cylinder Head and Cylinder with each incremental upgrade in Engine Output? A year later, I finally understood. Life took me in another direction so I never really publicized my book, other than being on multiple bulletin boards. A guy in Brazil who owned a Custom Intercooler shop wanted my book. I sold him a copy even tho I was still in the editing process; he adamantly wanted it - guess that makes me an International Author; woo'hoo. He later sent me an email stating he never would've understood why the engine behaves the way it does without understanding dynamic compression. Engine math is Terciary, not one dimensional. Once you know what I call the three overriding parameters, you can Transpose your equations and know ALL parameters of someone else's engine. Ive said all this so you know, I know what your going thru.., I feel your pain. In our passion to work on, build cars, enjoy their performance, and teach others, you will always run into the disinformation crowd. I call them the never wanna say Volume Cult. I call them the Volume Colt as they've bought into only knowing a Cylinder Head's Intake Port's Pinch Point Area Sq.In. and never address how that Pinch Point Sq.In. is relative mathmatically to a specific Intake Port Volume. They are of the Volume Cult mind; remember tho, they are your target market. You'll go thru 100 heavily brainwashed ppl before you find that one person that says they wanna know more. We wanna teach and pass on our knowledge because of that one person that wants to know more, so be patient - which you are. You can always get published by someone. However, with the internet - self publishing is always an option. Create your own website and automate the sale of your book, digitally. My book in paper form was over 600 pages. Once you have your book in Ebook format, your talking kilobytes. Bandwidth is much cheaper now days than it was in the late 90's. If you go the self publishing route keep in mind if you go cheap on the Bandwidth your website will buffer on your customer's end. Dont know if you are knowlegeable on how Bandwidth providers divi up the Tower wherein their websites are stored. If choose minimum bandwidth, your website is shared on a Blade within the Tower until that Blade is full. If you choose unlimited bandwidth, you get your own Blade, your customers are happy as there is no buffering. The problem I didnt like about trying to sell my Ebook was how easy it is to Page Copy from the Internet. Can you actually stop ppl from buying or copying your book, repurposing your book as their own, and what are you willing to do when someone violates your copywrite. Another question that I realized was how many copies would I have to sell to make my efforts profitable? Bandwidth costs from the late 90's was the hurdle I couldnt get over, maybe you will have better luck as bandwidth is cheaper now days. Anyway, hope I was able to throw some things at you to think about.
@kevinshasteen5682 I’m not to the point of being able to publish my work yet, too much to do, minimal time because my day job is teaching young automotive technicians engine operation, diagnostic practices, emissions technology and preparing them for ASE A1, A8 & L1, L3, L4, & G1. My student have passed over 65 ASE certification tests so far this year after completing my classes. I’m very proud of my students who push themselves to achieve their goals and get hired into the industry with guaranteed wages as apprentice technicians instead of being stuck in a lube pit somewhere.
I actually don’t like using “dynamic compression” at all. It doesn’t work, the science, physics and thermodynamics involved easily disprove its value. Modern automotive engineering has adopted “effective compression” as a result of the simulated Atkinson cycle and this is a scientifically accurate approach that addresses real conditions. You’ll like the next video.
And on the topic of hosting on the Internet, bandwidth is a concern, copyright infringement is a major concern, and how to disseminate the content is not straightforward at all. I know several magazine editors and automotive authors who have published books and articles over the past 30+ years and I’ll probably try to work with one of them to make a book happen with a known publisher when the time is right. There are a few of them who I might convince to lend their blessing to the book. Time will tell.
You are a teacher, explains why your so good at it; your students passing their tests are indicative that you are an effective teacher! Dynamic Compression is only ineffective if you use 1950's parameters. Dont dismis the process simply because the #'s are outdated. Update the #'s so your equation for the process will be updated. The numbers can blur the lines the more efficient your engine becomes. Fuel Injection can be very efficient, more efficient than carbs - some will argue otherwise. So junk #'s in equals junk #'s out which is why I changed my books title: it was incomplete on its own. Ppl's minds will open when they undetstand Dynamic Compression - so, its still a good teaching tool. Looking forward to your next video.
@kevinshasteen5682 I suspect your numbers probably lean hard on what is now termed Effective Compression to be able to get things right. I think you’ll find the next video a satisfying watch, and I’d be happy to compare more detailed notes via email after you’ve had a chance to see where I’m coming from with it.
Excellent! Great research and presentation. I’m working on a 1970 boss 302 that has suffered detonation and it forced the porcelain section of the plugs right out of the steel portion of the spark plugs. The engine uses a @13:1 piston. I’m pulling the heads on 11/25/23 I’ll see what damage occurred. Thanks again.👍
A 13:1 Boss 302 is a wicked combination, check the piston to deck clearance (should be zero) you want to really tighten up the quench area to about .040” (just the thickness of the gasket, no more. The closed chamber Boss/Cleveland heads do benefit from more cam duration and carefully chosen cam timing events to get the best out of them. In 11:1 or higher Cleveland and Boss 302 engines using iron heads, I install Autolite Racing AR25 spark plugs because they are a cold plug and produce good results. The AR25 is a much colder plug than an Autolite 23 (Autolite 25 is stock) or NGK UR5, I avoid platinum and iridium in these older engines, because they are designed to run hotter and self clean in modern engines with knock sensors and the computer can sense and catch the early signs of detonation that can wreak havoc on our older engines. I also run tighter gaps with high compression to improve the intensity of the spark, typically in the .028-.032” range with compression over 12:1 or when running boost (artificial high compression). Basically if your ignition system is up to the task, the cold plugs will work perfectly, you need a quality spark, but don’t want the spark plug acting as a glow plug. As for timing, the chambers are a good design, but I’m assuming you have a dome to get the compression that high and that really kills combustion efficiency. I shoot for the smallest chamber and flattest piston possible in small displacement engines, in big displacement combinations like a 408 Clevor, I use the small chamber and order a custom inverted dome piston where the dome mirrors the chamber and still nets that critical .040” quench area. You may find that you can give up a little compression and gain some power by improving the efficiency of the chamber.
@@TheGT350Garage thanks for all the info, it gives me much to think about. Yes I’m using Autolite25’s, car ran strong until my son let the fuel get stale during winter and then took it out on the back roads to warm it up. I suspect that the head gaskets are blown, yes it was zero decked. I’m using ARP head studs, also cam lift on paper was 0.540 but with the .030 clearance, if I go any tighter I run into coil bind. So maybe I should address all of this during this head removal. I dont have the cam card handy. Thank you for answering me. You can see my car on my channel called Laut Burns!
I'm currently building a .030" over Ford 302 with domed SRP pistons. With 60cc chamber heads it should fall in the 13.5:1 range. I've never built anything with that much comppression. I have got alot of interesting insight from your video, especially when you spoke of boosted applications on pump gas. I'll break the cam in, flat tappet solid, with Torco 112. Once the preliminary break in is performed I'll do a compression test to measure pressure. Thank you for the info.
13.5:1 with a dome isn’t ideal. The dome interferes with flame travel. Shoot me an email if you’d like some guidance on how to improve the combustion event and make the chamber work better with the dome. TheGT350garage@gmail.com
I watched the video hoping to hear some talk about Quench. Maybe I missed it. I am building a 460 Ford bored .040 over. The pistons are .036 below deck so I am having the block milled .036 to zero deck. With a Fel-Pro head gasket with .041 compressed thickness I will have .041 Quench. With my Dove C heads I will end up with 10 to 1 compression and hope to run regular pump gas if possible. If not I have some D3VE heads with 20 more CCs in the chamber which are more pump gas friendly. The problem is the D3VE heads need guides and also the pedestals converted over to studs for my roller rockers. This will cost some $$$. Hoping I can use the DOVE C heads cuz they are ported and ready to go with bronze guides.
I’m guessing you’re using a later 10.322” block and you don’t mention which pistons you’re running. If you have a flat top with eyebrow reliefs and you cut the deck to 10.300 you will be just over 11.2:1 compression. A dish will obviously be less, and the shape of the dish will play a major factor in combustion efficiency, by which, anything other than a dish that matches the shape of the combustion chamber will reduce quench area and impact flame propagation in the dish portion of the overall combustion chamber space.
The reason I wouldn’t cut .036 off of the deck is because with the large bore on a 460 the piston will rock on the pin in the piston to cylinder wall clearance space and you get dangerously close to contacting the head with the piston at TDC. A big bore like the 460 needs .055-.060” piston to head clearance to avoid collision, but that’s still great for quench.
Quench is a whole concept to itself that I will cover at some point in a future video. I’ve had some challenges getting content made for a while now, but I’m working on it.
@@TheGT350Garage Thanks for the advice. I have a set of Silvolite 1143H.040 with a +21cc piston volume. The block came out of a 1973 Lincoln Continental.
Take the deck to 10.300” and the D0VE-C heads. Take what you get for compression and quench. That piston is generic, the dish isn’t ideal, but the combination will work better than it would with the D3 heads.
@@TheGT350Garage I really appreciate the advice. The block is at the engine shop waiting for the pistons to arrive so they can mic them for the finish hone. I know the pistons are cheap ($220 for eight) but they are the only ones Summit had that were close to the CCs I needed. Diamond & Icon cost over a thousand a set. Keith Black also expensive. I will tell the machinist to go 10.300" and hope it runs ok with the Howard cams 240705-12 roller cam I plan to order. Thanks for your help
Honestly I would have used a Silvolite 3191H, compression isn’t the enemy. On 3.85 stroke with a 6.605 rod you’re .018” down the hole at TDC in. 10.300 deck, with a Felpro 1018 gasket. With a D0VE-C you’d have been right at 11:1.
Your cam choice doesn’t have nearly enough duration. In the 10:1 to 11:1 compression range a street profile should be in the 234-238°@.050” range on the intake with an exhaust duration no more than 6-8° more than the intake, the ICL needs to be at 112-114, with an LSA of 108-110° and .580-.600” lift on both sides.
We are just finishing up on 1964 fairlane 500 sport 289 c4 with 289 one dot heads with 1.84 ans 1.54 valves light ported big question on fuel and timing I'm almost 70 have building engines from 17 . the new cam profiles have thrown me on this one . talking to different people they said total advance should be 28 to 32 it did sound right to me . thank you for your info . maine .
That head has a small compact chamber but it’s a less than ideal shape. Depending on the pistons and head gaskets you chose and how you machined the block you should have no more than about .055-.060 quench. That keeps you out of trouble. Don’t run a traditional spark plug in that engine. I use the much colder Autolite Racing AR32 gapped at .032-.035” and it makes a huge difference in fuel sensitivity. It’s not the cam alone, it’s also the fuel that drives the timing down into the 28-32° range. Make sure you’re using vacuum advance On manifold vacuum and the engine will run nice and cool.
Very informative, you really appear to know what you're talking about, I'll be applying what I've learned today, I'm building an engine and as it turns out i was concerned that i might be a little over 10:1
10:1 is absolutely fine as long as your quench clearance is .040-.060”. Any more than that and you start getting detonation in the quench area. If you’re using a dish and it doesn’t match the shape of the combustion chamber that’s also problematic. But 10:1 is a good starting point. You want to make sure your cam duration and specifically the opening and closing events produce the ICL, LSA and thus overlap you need for best results. People tend to get in trouble by using too small a cam or running a larger cam that leans towards building too much cylinder pressure in lower to mid range operation, and that too complicates the process.
@@TheGT350Garage it's actually a 1.8 ltr. mgb engine, very slight dish, 6cc, kidney shaped chamber.
Presently at about 9.5:1, runs great on 93 octane but below that, I really have to back off the timing. the head is cracked across two seats, been running fine for the last 20k but feel like it's just a matter of time before it fails. I acquired another head but later found that it was skimmed .060 and think it would take me above 10:1.
I have I new stock cam and runs great, smooth idle. Do you think a light porting would positively tone down posible detonation, thanks in advance.... Luc S...
@lucsavoie9501 port the skimmed head lightly to improve airflow, simply working in the bowl to contour the guide bosses and remove any casting flash or machining peculiarities in this area of the port and profiling the combustion chamber to unshroud the intake valve, and lay the deck back down to the seat with a gentle transition inside the gasket opening along with getting a slight 1/16” or so radius on the chamber anywhere it’s exposed to combustion combined with a proper valve job, and you can make big improvements in about 4 hours time plus the valve job. Then get a “Fast Road” type cam with duration in the 260-270 range to take advantage of both the compression and flow, you’ll have a very fun little combination. The one thing to consider is the piston to deck clearance, I generally build to 0.000” and set piston to head clearance with the gasket. Ideally you’ll want 0.032-0.035” clearance, if that clearance is more than that because the piston is below the deck, and you can’t get a thin enough gasket to get in that range, consider decking the block. It will further increase your compression but substantially decrease the likelihood of detonation in the quench areas.
Great video! Thanks! So this video would seem to be a lead into how to shape a combustion chamber (maybe among other things). I just subscribed so haven’t seen what you have for other videos yet, but will, but if you need new topic and it’s not covered in current videos, that how to shape a combustion chamber would be of interest. Thanks!
Very interesting and informative, great to hear as I'm currently working on a 11.8:1 4.6l and was worried I'd be stuck using e85 or water methanol. Can you clarify exactly how you are using the specific heat ratio? You stated the cranking pressure in the cylinder was equal to the product of compression ratio, atmospheric pressure, and specific heat ratio (Ptdc = Patm*CR*λ) and thus removing the effects of heat addition from compression would require dividing by both the measured cranking pressure by the specific heat ratio and atmospheric pressure to obtain the dynamic compression ratio (CRdynamic = (Ptdc/λ)/Patm). This would only hold true if the adiabatic process were linear (P*V*λ = constant), which is not accurate. I think what you may be referring to is the polytropic process relation which is P*V^λ = Constant. Thus the equations from your examples should be Ptdc = Patm*CR^λ and CRdynamic = (Ptdc/Patm)^(1/λ) respectively. For the second example worked out that would be CRdynamic = (155psi/13.6psi)^(1/1.4) = 5.68, significantly lower than 8.1. The relation between pressure and temperature is linear. However, within a confined space, as temperature increases proportionally withpressuree, the heat created causes a further increase of pressure which in turn causes an even further effect on temperature and so on. This results in an exponential relationship when gas is compressed in a confined space, an exponential relationship with a coefficient equal to the specific heat ratio, 1.4 for air.
en.wikipedia.org/wiki/Polytropic_process
I appreciate the thought that went into the comment but there are other factors you aren’t considering. The ethanol content of the fuel has a cooling effect that negates some of the heat, as does the pressure drop into the cylinder, much like expanding a refrigerant to create air conditioning, the void created as the piston moves down the cylinder is going to cause a low pressure for the air-fuel charge to expand into and that too will cool things down, so it negates much of the heat you’re adding in using polytropic calculations.
Sometimes it’s better to simplify than over complicate. This is one of those times. Otherwise we would have to calculate the rate the cylinder volume increases and plot that against the flow of the cylinder head, at which point we would see that the expanding volume is greater than the head flow initially. Then we would have to factor the speed of the crank, the length of the rod and the acceleration and deceleration of the piston against the speed and mass of the airflow, at which point we could roughly calculate how much air flows past the valve while the piston is in a practical state of dwell near BDC.
Easier to run a compression test, take a pressure and see that it is more or less efficient than the static compression ratio as a determination of overall pumping efficiency and potential volumetric efficiency / performance.
I never was to much for going by what some book told me about setting Fuel or ignition timing! What I did find was I make the most power, the best ET when my plugs are the right color, and the ignition burn is on the curve of the ground strap of the plug. What I did find is the timing is about 4 * less with today's 94 octane than it was with the old premium. I used to run 36 * now it is around 32*. i thought it was because of the Aluminum head I use now.
The difference in timing is primarily because modern gasoline burns faster and more completely. Reading plugs is a good start, but it doesn’t capture the complete picture. Ideally, a tuning session on an engine or chassis dyno is the best way to find the ideal A/F Ratio and timing curve. But when those aren’t readily available, you can use a wideband oxygen sensor, a pyrometer (EGT Probe), and a simple stop watch to find exactly what the engine likes.
I have done some experimenting with varying comp. ratio's. Intake valve closing is important to how much charge is trapped in the cylinder affecting the dynamic comp. ratio. Playing with high comp. and short timing on cams for cyl. pressures of 210 220 psi was an experiment for economy. This motor needed nothing but standard tuning at 5000 ft. but under load under 1000' was preignition. Using water/meth injection stopped preignition. Later a longer cam install completely cured the issue. I run an old Ford 351C on 11.3 comp. with iron heads and the camshaft makes it work great.
If a 351C uses a relatively flat piston and has .035-.050” quench with a closed chamber, that’s most of the battle. 11.3:1 needs an IVC event around 75-85° ABDC at .004-.006” (286-294° Advertised Duration) or 45-55° ABDC @.050” valve lift using a cam with about 234-238° duration @ .050”. ICL needs to be 112-114° at that duration to close the valve in the correct window. Using an LSA of 108 or less is too tight and disrupts idle and causes drivability issues, 110-114 depending on the final duration number is the range to be in to manage overlap, 116 and up is unnecessary except for extreme setups trying to run 255° @ .050” or more on the street, and there’s no benefit to a cam that large below about 13:1 compression. Cam specs are super important, but following some of the long time standard advice to advance the cam and tighten up the LSA is not conducive to quality results and just nets a lousy idle quality and pesky torque curve.
My little 2.3L DOHC builds 20 or so years ago were 11.5-14:1 compression. I ran durations ranging from 226-256 @.050” and degreed them on install but adjusted them on the dyno to optimize power. Each grind had its own characteristics and each compression ratio had its ideal grind. At just under 140” displacement, to make 285-315hp at the flywheel naturally aspirated in the 7500-8200rpm range depending on the build was a pretty decent result back then, and most of them ran exclusively on 91 Premium pump gas. My 12:1 “street” build was 265hp on 87 octane and managed 35mpg on the highway at 75mph or so. Funny side note, the 2.3L DOHC heads ported flowed more than a lot of 4V Cleveland head with epoxied runners and port work, and with near 4” of stroke the ports moved a lot of volume, we were regularly over 100% VE with those engines.
Very helpful, I have a 1968 AMX with an over bored 390 at 11.7 -12 comp ratio static, with cyl compression tests at 200 to 205psi cold. The cam is an old sig erson solid lifter 320 hi lift w 45 degrees overlap, induction is a low profile dual quad offy with a pair of 500cfm carter competition carbs, I can also run dual holley 650's or a single holly 850 carb on a torker manifold. I believe a tunnel ram would work best but I don't want to cut my hood for the street as I could get pinched for vision issues.Pump gas detonates at idle, and has been the biggest headache to deal with. Also with electric fans and a flex fan with a shroud she runs hot. Oiling is a high volume milodon with a scanne rand cooler, and valve timing can be adjusted with the gear drive . ignition is MSD or a crane Hi fire. on a mechanical advance only distributer Where do you think is the best place to start, I've considered fooling around with the valve timing and advance curve. The car runs rich and doesn't bog if the clutch is let off a 3,500 rpm but pulls best starting at 4,500 rpm to red line, the engine can do more to 8,500 rpm before no more power is felt but then the mains are trashed. I also considering a hyd street roller cam if there are any for AMC, and running a single carb maybe a 750 cfm vacuum 2ndrys to calm it down for the street. Any thoughts.
I thought I had responded to this, so apologies for the delayed response. The cylinder pressure is a little higher than some like, but not terribly so. If it’s not beating up valvetrain parts, it’s probably ok to keep the cam and compression where it’s at.
If you’re at sea level, 14.7psi, you can determine the effective compression ratio from your cranking compression. (205/1.4)/14.7=9.96 so call it 10:1. That’s effective, not static or dynamic. If you’re above sea level pressure drops .5psi for every 1000ft elevation. This would only mean the effective CR would be higher.
If that’s an old school cam grind, the numbers may be advertised numbers and the cam may be much smaller than you think, ideally compare numbers from the @.050” duration to get a better sense of how big the cam really is. More cam could lower the cylinder pressure and make the engine easier to tune without giving up performance.
Awesome Beard brother!
Agreed with a lot except the muscle car era from 64-74 considered 8:1 high compression. From 64-70 the compression ratios were almost always over 10:1. After 70 they continually dropped
The cars from 72-81 that were still remnants of the 64-71 era were all neutered by emissions laws, but those cars are often upgraded to use higher compression ratios and have their emissions equipment removed. It’s nitpicking at best to include those lower compression ratios in the discussion as “muscle cars” because the muscle was gone and they were just cars at that point.
This video will remain relevant!
I’m really enjoying these videos! My 69 Mustang has a 351W with a carb and stock distributor. I bought some old school tools NOS - a vacuum gauge, timing light, dwell meter, etc and I like trying to learn what seems to be a disappearing set of skills…..These videos really help us out here! Keep up the great work!
You are in luck, because there are more videos coming to dive into how ignition timing can needs to be set up, how to address the various functions of carburetors to achieve ideal air fuel ratios under various conditions, and how to use the tools that are necessary for making it all come together.
Hi Walt. Guido here. I am running like 5 gallons E85 to 10 of 91 chevron here in SoCal. With that amount of Corn fuel. Do I still adjust on my 4160 holley 1.5 turns out for Air Fuel mixture or a different setting
Keep up good videos.
Running 12 Degree initial. Total about 28-30 I believe.
@@luckyluciano4968 we should talk about this witches brew of fuel you’re using, it’s too hard to duplicate if you find yourself in need of a refill. It’s far better to run a commonly available grade and tune to it. I suspect you’re probably quite lean with that mix unless you’ve jetted up substantially. And that concoction would require substantial changes to the carb to make it meter the correct amount of fuel, beyond jetting, you’d need to get into the air bleeds, the PVCRs and do a fair amount of tuning. Your timing is in the range for a 10.5-11:1 compression combination, but until you get on top of the air-fuel ratio and get it optimized to the power potential of the engine, your timing settings are a wild guess at best.
@@TheGT350Garage I havnt jetted differently I was just trying out the E85. It’s a stroker 331. Is it spec out at 10.5-1. Coast High Performance in Gardena. Built the engine back in 2014. I don’t plan to keep it in the system. Gave it a little more pep. Havnt mess with anything Thanks for your input.
Just to put this in the simplest terms, 5 gallons of E85 (85% Ethanol) 108-octane mixed with 10 gallons of California spec E10 (10% Ethanol) 91-octane will produce E35 (35% Ethanol) 95-octane fuel.
While that seems “good” it’s really not because you have to look at the effects on the stoichiometric air fuel ratio for each blend and that’s what determines what is rich or lean for the fuel.
Gasoline has a stoich point of 14.7:1. Ethanol that has a stoich point of 9:1.
When you blend them the stoich point “moves” with the blend ratio.
E10 (10% Ethanol) 91-octane has a stoich point of 14.08:1.
E85 (85% Ethanol) 108-octane has a stoich point of 9.85:1
Your E35 (35% Ethanol) 95-octane fuel blend would have a stoich point of 12.70:1
A 331 Stroker with 10.5:1 compression and a typical street type hydraulic roller cam grind (425-450hp) is going to make its best power on ethanol free gasoline at an air fuel ratio of 12.8:1 to 13.2:1 and 32-34° of total timing. The timing would stay relatively the same and at most 1-2° less depending on the fuel used for any of the various aftermarket head options and their different combustion chamber designs in concert with the various cam profiles that would all result in similar performance.
What’s important to realize is that for the engine to maintain its full power output capabilities, you have to maintain the same amount of fuel energy and that’s why we need the Lambda number I talk about in the video. So knowing that straight gasoline with a stoich point of 14.7 makes best power at 12.8-13.2 we divide the A/F ratio by the stoich point to get the Lambda value range of 0.87-0.90. If you apply that range to the ethanol blends we’re talking about, here are the numbers:
E10 91-octane (14.08) 12.5-12.7:1
E85 108-octane (9.85) 8.6-8.9:1
E35 95-octane (12.70) 11.1-11.4:1
In this day and age you need to verify the air fuel ratio of your tune. It’s just flat out important. And in most cases, you will need to adjust the carburetor jetting to optimize the air fuel ratio for the fuel in your region. Being in SoCal, you can’t get Ethanol-Free fuel that meets CA emissions requirements. Here in the Rockies and all over the midwest, Ethanol-Free is commonly available, and at the lower elevations with as much as 93-octane.
These are the challenges of tuning cars on modern fuel. It’s not that the fuel is bad, it’s just more complicated. If you can take the time to understand it, it’s actually very capable and will do what you need it to do for you.
Hi Walter, great video. When you sight cam spec values i.e.: "intake closin point" are you using advertised or @ .050" numbers ?
I use @.050” values not advertised because advertised values are really inconsistent from cam to cam. The cam manufacturers have enough variation in their advertised numbers that they’re basically useless for comparison or any true closing point determination. Also, at .050” the valve presents as closed to both sides.
@@TheGT350Garage That makes sense,.. you never do see flow numbers posted for .050" values... lol. Thanks for the reply. Keep up the killer content. 🍻
@Torquemonster440 the flow at that point t is quite minimal.
I'm going to use a AFR gauge to help my tuning process. My new build is LEAN on the plug and it has many hiccups in the slower throttling process. This info is great. I have a friend that says modern fuel is trash. I argue with him about it. The carb I was running on a stock engine worked great. New carb, not so much. I've made soooo many changes to this engine it doesn't want to run hard past stall speed of the converter .
Once you pass the stall speed, the load on the engine increases. You probably need to look carefully at timing as well as fuel. I would suggest a vacuum gauge as well as the AFR info, you can judge load from vacuum, and you can use that to judge the appropriateness of the A/F you’re seeing.
Thank you for this video!!! I just had a Studebaker Avanti R1 engine custom build for my 1955 Studebaker Commander Coupe. My son and I will be breaking this new engine in shortly. It is suppose to be 10.25 t0 compression ratio, so I am concerned about timing and carburation. any ideas you might have will be welcomed. thank you again Steve clark.
Steve, check your email for a response, and if you have any questions please reach out again for follow up responses.
Very informative, 10:1 is common on euro cars and I’ve had several. I now understand the octane rating better, when I was 16 I had a 2007 328i that should have been running on 93 octane. I ran it at 87 or less and ran it hard, for a bout a month. Couldn’t figure out the knock and overheating issues. Now my 2003 330i runs ethanol free 91 octane only with no issues 😅
Absolutely great Informative video !!.....I've been searching the net for the elusive Compress air Heating Factor (1.4) & You clearly provided it.....The "On Line" Dynamic CR calculators are all over the map, typically using 0.050", cam card lifter Check Height or Unspecified IVC input data, None of which is Actual physical Intake valve Closed timing point.....They all Can't be Right !! .....Even if you Use the Actual correct IVC, at typical Cranking Rpm, the valve Overlap Is allowing the Air/Fuel mass Inertia "Plug" to slightly Overfill the cylinder Beyond the Calculated IVC cylinder Volume.......I always Suspected the typical Calculators are computing an Erroneously low Dynamic compression ratio figure....This new computing method may be more Accurate than the various IVC Calculators......Thx for the Helpful video......
I teach engine controls and that includes VCT/VVT operation modes. Newer production engines are using late intake valve closing to produce Atkinson Cycle operating conditions. To operate in that cycle the closing event needs to be able to move from as little as 30° ABDC to as much as 120° ABDC seat timing. My cam isn’t “huge” and it closes on the seat at 81° ABDC, 55° ABDC @.050”.
The way the calculators determine dynamic compression simply lacks any accounting for the rest of the physics involved and completely ignores the compression to expansion ratio of the engine which is equally important.
So is this method good for any engine or only Fords?
The principle applies to most engines. There are always exceptions, but I’ve used these methods on Ford, GM and Mopar engines with solid results. I’m working on a follow up video on how to dial in the timing curve step by step that I hope to have up in a week or two. The process works, and I’ll show some great examples in the process.
That all made sense (I had to rewind quite a few times). My question is; do the same rules apply to tuning lower compression engines. I have recently rebuilt my 1962 Triumph 650 which has an 8:1 c/r. By chance the new carburettor came with a 2.25 (?) jet where as my old one was 1.8?. There was a fair guess made at the timing advance as the notches in the gear do not match the positioning stated in the manual so "the right sound guage" was used. Can I assume that having the larger jets will paper I er the fuel density issues of using E05 (95RON) or E10 (97 RON). Note that in the UK there is a 5% price hike on E05.!
Also will adding an ethanol fuel conditioner affect the fuel density factor to any noticeable degree.
Thanks. Mark
So, ethanol isn’t quite the demon it’s made out to be. It has some positive effects on combustion including better vaporization which has a cooling effect on the combustion process. Most “Ethanol” conditioners or additives for ethanol fuels are just methanol and fuel system cleaners. If the car will go into winter storage for more than 4 months, I’d use Sta-Bil or an equivalent product to keep the fuel fresh and fill the tank to 95-97% for storage to limit the amount of air that can oxidize fuel. Otherwise there is t much to be gained from ethanol fuel additives.
As far as your jetting, you typically need to jet up a bit for E10, and that could do the trick. Also, your new carb may have a slightly more modern calibration to combat not just the changes in fuel, but also to run an air cooled engine a bit on the rich side to manage cylinder temperature better.
@@TheGT350Garage Thank you for your advice regarding the additive route. The carb is a new AMAL and for your advice on running a bit rich. I'd wager that there is no refining of the carb....🤭
...note the pipes blued up very quickly so it may already beset a bit lean
Amazing video!
Thank you for all the information 🙏
I’m definitely going to have to watch this a few more times to let it all sink in. 😊
Great video but I would like to see some actual hands on tuning, how does the typical guy tune a carb and timing without a Dyno or high dollar equipment that the average person can't afford? I'm not complaining it's a great video. Tks.....
That’s in the works for sure. The distributor curve video I did shows how to make the change’s internally in a Ford Autolite or Motorcraft distributor, Mopar and AMC are very similar, GM is easier. As far as the process of figuring out where you are and where you need to be, that is a video that is waiting for me to have a running engine to film the process, and the same goes for carburetor tuning. Now, I will say, there are some basic tools at minimum required for tuning, timing light, vacuum gauge, but you will also need a wideband air/fuel ratio gauge and sensor. It’s a small expense relative to dyno time and stays with the car. All of this will be covered as I get the car out on the road for tuning. A final item is a g-meter and stop watch or digital accelerometer to measure acceleration over time, which is exactly what a dyno does. You won’t get an exact horsepower or torque number but you can measure gains or losses from changes to air/fuel ratio or ignition timing, and that’s more than enough in most cases. I’ll cover all of it in detail soon.
Gotta pause at 25:53 to say that's not how reduction works. Reducing by 25% numerically is not the same as doing so mathematically. 10/1.25 is 8. Just the same as 8*1.25 is 10. If you remove 25% (this is different from reducing by) then you get, numerically 7.5, yes. But that is a 33% reduction. IDK what this phenomenon is officially called, but I call it inverse decimals.
*Post view EDIT:* Okay, so if we have a choice in the matter or need to make an informed decisions, what part of the octane rating is more important for enthusiasts? The RON, MON, or AKI? I would assume MON since that's based on higher load and unfavorable intake temperatures, signifying a worst-case scenario. Also, given this inquiry, once decided, is there any direct correlation between octane rating and compression? IE does an 86-88 MON rating mean that I can safely run 8.6-8.8:1 dynamic compression, or is it indeed, higher, more line with the AKI or RON rating?
If you have 100 apples. And I take away 25% of your apples, you have 75 apples remaining. You’re calculating the difference between the final product and the original product and if we started with 7.5 and wanted 10 it would require a 33.3% increase to get 10, but we are subtracting or losing 25% here, so it’s 7.5:1.
Comparing fuels is challenging. AKI is great for pump fuel, but race fuel in a can requires you to do some research. To call it “race gas” RON will be 100+ and AKI will be 96+ but even then it’s not that simple.
@@TheGT350Garage Fair enough... Though you didn't really hit on MON since it's rated under extreme stress (300 deg plus intake temp, 50% higher rpm) compared to RON(120 deg intake temp). Wouldn't that be a better metric to look at for performance engines? Seems like if the MON is particularly high, that means the fuel would be particularly less likely to grenade your engine under driving conditions that would cause catastrophic failure in the first place.
Another thing that I've read, and this is from David Vizard, himself, is that water has "infinite" octane, and therefore water injection (not even water/meth, he says JUST water) can allow you to run up 14:1-17:1 on 87 octane fuel. What's your take on that? Is that even useful for the street or no?
@Drunken_Hamster David Vizard is brilliant, but there is a point where practicality has to be a consideration. What happens if you are driving and you have a water injection system failure? If you tune for water or water/methanol, you have to rely on the system to keep the engine from experiencing detonation, I’m a fan of simplicity, and water injection is not conducive to simplicity.
As for MON, it’s not as readily accessible for fuel information as RON or AKI. AKI being the average is honestly the better choice for comparison across all types of fuel, but performance fuels don’t always include the information in the documentation. Again, simplicity being key to success, using a single standard for measurement would be ideal, but this industry isn’t as good about getting together and adopting standards as it could be.
@@TheGT350Garage I thought so on the water injection part. And thanks for the perspective on both! I haven't watched your second video yet, but it's in the queue.
After all, I might end up throwing a 302 or 331 stroker in my Ranger some day and I'm learning a lot beforehand so I can do it right and put the whoopin on them 05+ muscle car boys.
Especially them fat Mopars and my brother's 2012 SS.
Sir, I have a question, My VW 1.0 TSI has a compression ratio of 10:5:1. It says "Minimum RON 91, Recommended RON 95" (these are for EU spec,,, for american spec would translate to 87 and 91 octane respectively).
Am I ok with 91 RON or should I be religious with 95 Octane?
I want to hang on with the car for atleast 200K miles.
I am a very sedate driver, always drive on the highways and almost never exceeding 2.5K RPMs.
What do you say?
It’s easier to extract the potential from a lower octane at lighter demand. With 91 RON being the “Minimum” per the manufacturer you’re certainly safe to use it. If you were working the engine harder, you’d want to use the 95 RON. Choose a top tier fuel (a brand or brands recognized for selling a higher quality product) and perform your scheduled maintenance on time or a little early.
Hi and thanks alot for the info. Engine head I did a few years ago and not knowing how to measure the chamber turns to result in 12.87:1 comp ratio (it's been 9.5 stock). Also running an old racing cam, lots of duration, not to big of a lift and it should have some bigger overlap resulting in lower dynamic comp ratio. I tought I will dump the head or take some meat from near the intake valve to make the chamber bigger. I will try to measure the cam so I know exactly what I am using. I will watch this video again to try to have a better understanding on timing I should use and jets. Also, I heard "because of that high duration cam you need stiffer distributor springs or remove the vacuum advance from the distributor and preferably an adjusting cam pinion". What do you think about this? (I wrote this before watching the rest of videos to not forget something). Also, I don't have enough money for special made stiffer valve springs to prevent valve flow. I saw some guys putting shims under the springs, what do you think?
Wanted to add that the engine it's not yet built.
Thanks for the intel, can't wait for new stuff to be posted!
Blew my mind.totaly covered things I've often thought about but never found out.very very informative.thanx..im 13.7 to 1 with lots of the issues you mentioned. Mainly 110 octane on the street at 5 mpg@9$ a gal. It's parked on you tube @. Ole ridge runner race truck
While it often gets called de-tuning, the reality is that tuning is finding what the engine wants. Here’s a little food for thought: 9:1 static compression is calculated using 14.7psi atmospheric pressure at sea level, which is why a typical 9:1 engine pump’s slightly higher than 150psi (9 atmospheres + 1 atmosphere). Take that 9:1 engine and supercharge it with 7.5psi manifold pressure. That is roughly 1-1/2 atmospheres. Now the engine is compressing 14.7+7.5 = 22.2psi. 9:1 at 22psi is close to 220psi and we ran that on supercharged 5.0L HO Fox Bodies in the 90s with minimal tuning. Your 13.7:1 compression is not much different except for it being there all the time not just at high rpm. 13.7 atmospheres + 1 atmosphere = 216psi. There really isn’t much difference difference between tuning a 13.7:1 450” engine and a 9:1 300” engine with 7.5psi, they both have about the same cylinder pressure, if one was a 351W based stroker and the other was a 302 based forced induction engine, and both used the same head and combustion chamber on a flat top piston, you’d be shocked to find that while the forced induction engine would have a higher BSFC the timing would be nearly identical. The point being that if you can run a supercharger and have the equivalent of 13.7:1 compression on 91-93 octane, you can run 13.7:1 on pump gas if you take the time to understand what the engine wants.
@@TheGT350Garage yes sir I have learned that hi octane fuel is kind of a cheep fix for poor tunners .thanx for the insight
I run a 540 chevy in a nova with 11:1. Solid roller, all the goodies. 850 hp. I run Holly FI. So nice and tunable. I use 94 ultra. 13.6 af and 30 degrees total timing. No problems at all. Nice thing is i can alter my af for different fuel if 94 is not available. 91 octane i run at 13.8 with 32 degrees timing. Very fun car to drive.
Might want to rethink the idea that 91 can be leaner and have more timing. That’s not usually the way the fuel responds. 94 Ultra has a stoich point around 14.2-14.3, and 91 will be closer to 14.1-14.2 depending on the source and season. That puts you at .95-96 Lambda on Ultra 94 and .97-.98 Lambda on 91 octane, which, respectfully, is a recipe for disaster. Even “IF” stoich was 14.7 and there was no ethanol content in any fuel you were running, you would be at 0.93 Lambda on Ultra and 0.94 Lambda on 91 octane. Most high performance naturally aspirated engines need to be in the 0.86-0.89 range to be safe for regular use on the road, especially in the transitional range below to just above peak torque.
I ran a Pontiac 350 with 10.5 compression with a 274xe with 110 lsa . I ran it with vacuum advance . Total mechanical timing was 34 degrees when the vacuum pulled in , it was at 47. I ended up squashing the piston rings and deforming them ...losing compression.
Pulled the engine and got a 400, bought TRW pistons and tool steel piston rings capable of withstand 48,000 lbs of pressure without damage. Also bought a summit cam RAIV can 235/245 112 lsa. Set the timing at 34 total, ditched the vacuum and plugged it. Runs well, but if I run 89-91 octane, it's very hard to start when hot. If I add 102 real race fuel, it starts with one stroke of the crank. Obviously octane makes a huge difference.
It still has 10.5 compression
The only way you can get 47° under load with vacuum advance is running ported vacuum. Manifold vacuum will be 2” or less at WOT and you’ll have 34° at WOT. That’s why I take the time to explain the difference, and if you skipped through the video you probably missed that part, and your comments would be more about the mistake you made using ported vacuum than trying to blame vacuum advance piston failure.
You probably have too much initial timing and likely have a secondary issue with your starting circuit causing slow cranking. The only reason 102 “real race fuel” would make it start better is if it had a lower ignitability that caused it to make combustion pressure later or after TDC. Back the initial timing off and 91 octane will make pressure at the correct time for the engine to start normally.
Didn't mean to misguide the port vacuum with manifold vacuum. I installed the vacuum on the manifold, so when the engine is at WOT the vacuum goes to zero. It's when you start letting off the the throttle gradually, the vacuum goes sky high along with it goes vacuum timing , now your banging at 47 degrees and fuel is still moderately rich, causing detonation. I heard it with my 350 , not going to grenade my engine to try to experiment. I'll take the loss of HP, unless you have a way of doing it that won't destroy my engine .
Good video , just a little hesitant.
@@johnszoke586 there is a reason I’ve made a good living tuning engines and now I teach and develop training for engine performance, drivability, and emissions compliance for one of the largest auto manufacturers in the world. Not bad for a guy without a degree.
Your issues are not unique to your combination, and they are all correctable, without the need to perform experimentation or put the engine at risk. I do these videos to help people like yourself learn how to get the best from their setup, not to argue with them. The only way that works is if the viewer has an open mind to listening and learning. If you ask for help, that’s what you get, and if you complain or argue, well…
It’s all in the camshaft (valve timing) as to not trap too much air in the cylinder. I ran 11:7+ on pump gas in the 80s in a Cleveland ford engine with nothing special , just a cam designed for good pump gasoline. Keep you cranking pressure down with overlap and timing. 12:5 static is no problem. Call your grinder if in doubt.
Cleveland 4V with closed chambers wants compression. The improved combustion pressures get the ports activated because the piston on the companion cylinder accelerates at the same rate as the piston on its power stroke. Bigger cams become more effective as a result. It’s not about valve closing and dynamic compression though, that number is actually pretty meaningless, and the only reason it continues to be used is because everyone wants to run too much ignition timing at lower speeds and detonation is the result. You talk to cam grinders and they all push advanced cam installations, yet the closing point is the supposed secret to success with respect to cylinder pressure, and those two things are in conflict. I’ll be sharing my full thoughts on dynamic compression in an upcoming video and it’s going to explain a lot about how the engine combination works and why dynamic compression is utter BS.
@@TheGT350Garage
I'll be looking for that.
Great video! Love the true/accurate information on how to exactly measure by providing proper formulas to meet the engines needs based on usage. Two questions, 1. How do we adjust fuel enrichment and the taking of timing out based on weight of vehicle to avoid detonation issues? 2. Do you have videos on how to match a camshaft to the vehicle for getting the best performance for a street machine? I have been struggling to find a complete video or set of videos on how to find proper LSA, duration, etc. for example, David Vizard is a believer of lower LSA for small block chevy’s e.g. 108°. He claims great performance, smooth idle,etc. But, all the pulls on the Dino start at 2500rpm. Thank you!
So, I did a follow up video where I explained how to use Lambda (combustion efficiency) instead of air fuel ratios for adjusting fuel. Ideally you’ll be in the 0.85-0.88 Lambda range for optimum performance on pump fuel. Lambda is independent of the stoichiometric ratio of the specific fuel you’re using, because it focuses on the completeness of the combustion process for the specific fuel you are using. Adjusting timing and fuel should be a rough timing adjustment somewhere less than you would expect peak power (2-3 degrees less) prior to adjusting lambda into the 0.85-0.88 range, then a fine adjustment to timing to get peak torque across the range.
As for cam selection, I like a wider LSA than DV recommends in most cases for a street car. Typically I like a 112° LSA on a SBF. But in conjunction with the wider LSA I also prefer the ICL to be in the 112-114° range, not the 102-104° range that gets so much attention. What I’ve found is that the ICL has a far greater impact on idle quality than LSA, and simultaneously running the ICL about 10-12° “retarded” improves cylinder filling at higher engine speeds extending the usable power range while also improving idle quality.
Just retarding the ICL would also retard he ECL but increasing the LSA advances the ECL.
For a cam with a 110° LSA using an ICL of 110° ATDC, you would have an ECL of 110° BTDC.
Example 1: Retard the ICL 4° to 114°ATDC and the ECL moves to 106° BTDC on the same LSA of 110°. Overlap does not change.
Example 2: Widen the LSA to 114° with the same ICL of 110° ATDC and the ECL moves all the way to 118° BTDC. Overlap reduces 8°
Example 3: Retard the ICL 4° and widen the LSA 2° to 112° and you get a cam with an ICL of 114° ATDC and an ECL of 110° BTDC. Overlap reduces 4°.
In example 3 you retain the same ECL and this the same exhaust closing event, which is critical for scavenging the cylinder and creating a vacuum in the cylinder at TDC. By opening the intake valve 4° later you spend less time with the valve hung open during piston dwell at TDC and ultimately produce a better idle quality.
It’s often argued that retarding the cam is only done for emissions and that it hurts low speed torque, but I’ve found that the losses are negligible off idle and the overall power delivery is more linear and efficient, with substantial gains to be had in average power across the range, and often 600-1000 more usable rpm at the top end.
The one caveat to all this is you need to set up the vehicle correctly to make use of the power curve, and the rest of your components need to match your engine combination in a complementary manner.
@@TheGT350Garage I saw something about Lamda toward the end of this video, but how do you adjust it to weight of car? Heavier the car or truck, the more susceptible to detonation. (Maybe you answered this already and I am not understanding)
I really love your approach. I have a 403ci small block Chevy. I was wondering if you have an email I could message you privately to pick your brain some more. I have built engines before, but have not gone into this depth to get the most out of the engine. I would appreciate it if you would be willing. Thanks!
So, I do have a follow up video detailing the difference between fuels and focusing on the importance of Lambda. Basically lambda is a measure of combustion efficiency where ideal combustion is the relative stoichiometric ratio of the fuel in use. Most performance applications will make optimum power from a Lambda value of .85-.88 with rare exceptions getting as rich as .82 or as lean as .92 lambda.
You’ll want to target a timing value 3-4 degrees below optimal for dialing in fuel, get in the range for fuel and then dialing in more timing, readjust fuel, and repeat. Ideally a loaded dynamometer is the fastest and easiest method to dial it in, but any method of measuring acceleration over distance and time will suffice as long as you test in a repeatable way under the same conditions.
My email is in the video description.
Very good video... You won one more subscriber
How do you get your specific heat factor for the fuel/engine in irder to do your compression ratio?
Specific heat is a physics a thing that applies to different gasses. For atmospheric air, it’s a multiplier of 1.4 (nitrogen and oxygen are both 1.4 and make up 99% of atmospheric air) and factors into the temperature and pressure increase. I have a video coming up soon that will dive much deeper into compression.
well put..as a mech engineer, i find no faults in your system..thanks
Thanks. There are certainly some who disagree with this, but I’m ok with that.
Excellent content long time old racer here and what your talking about is true about dynamic timing with cam event timing . It’s easy to make power with boost it’s almost cheating I still like NA with 100% methanol . After track testing only ign timing after 33-35 degrees has no effect on MPH In my case . 14.1 Compression ratio mechanical injection SBC. Thank you.
Every fuel behaves differently but all fuels are predictable. Ignition timing is mostly about getting the peak cylinder pressure in the right place, some engines even like a bit if high-rpm retard. Cam timing is another discussion completely, and one that has to be had when discussing cylinder pressure and ultimately ignition timing. 35 years of doing this and I’m still learning new things, things that cause me to try new ways of approaching engine building and car construction as a whole.
@@TheGT350Garage you are 100% I’ve been racing since 1971 still racing have a national record still feel I’m behind .I’m impressed with your knowledge and that’s hard too do.
I appreciate the kind words.
My 2.6 liter I'm going to increase its compression from 8.7 to 1 to 10 to one on street gas I was reading that it can take it is that reasonable
If you are increasing it correctly by reducing quench areas you’ll be fine. Ideally you’ll want a bit more cam, but if you’re not changing the cam, you’ll want to retard it a few degrees to get the most from the added compression.
Good job but why won't my linc mark 8 4 cam engine start on the new fuel or this corn fuel it will not run????
The ‘93-98 Lincoln MK VIII 4.6 DOHC engines are tuned for 14.7:1 air fuel ratios. If you’re having starting issues with E10 fuels, that could indicate other issues. With E85, it should barely run if it starts at all on the stock tune. E85 without tuning will set lean codes. I teach modern diagnostics for a living, there will be codes and a diagnostic path to follow if you use the OE Ford/Lincoln service manuals and the correct diagnostic tools for the era.
I watched a video by David vizard about ignition timing that confirms everything you was saying about timing. Another thing that comes into play is bored size and chamber size/shape. The more efficient the chamber shape the less timing you need which means less time for knock to occur
I’m doing a couple of follow ups to this video. I’ve decided I need go into far more detail about ignition timing with one, and dive deeper into the fuel discussion in another. I’ll also be doing some additional video content that will simultaneously support my assertions in this video, explain the content I’m sharing better than the presenters, and probably stir up a bit off a fuss unintentionally.
very informative ,
i’m just finishing a 408w and looking for tuning help. Do you remote tune ?
I used to, but don’t now. Remote tuning on EEC-IV stuff was a headache, but the ‘96-10 OBD-II cars were doable, if the owner installed a Wideband O2 and set up the logging correctly,. The ‘11-up engines are fairly easy. Here’s the issue, I don’t do “off-road” or race only tunes, and the car needs to be compliant to either Federal or State emissions. That’s almost never the case, so to protect myself against the EPA,et-al, I stopping tuning late model applications for the general public.
Great video the content on the change in the modern fuel ,thanks for the video ,im gonna share this with my group of friends
I run a 68 Cadillac, 93 Octane. 472 10.5/1. Gas really was low octane back in the late '70s early 80s. I used water injection ADI on my high compression engines then. The 93 Octane is OK now. It's not Sunoco 260 or 100 / 115 low lead Avgas but you can run if you don't go nuts with the timing. Want to go nuts with the timing? Run ADI.
The reason you can’t “go nuts” with the timing is modern fuel burns faster, not because it is bad.
You certainly are thorough.
Preignition is early ignition detonation is when multiple flame fronts collide.isooctane against normal heptane.
Preignition is ignition before the spark. It can occur as a separate event from the spark ignition and still be a detonator event.
This guy us a Rockstar engineer!
I do a lot of research into the subject very good explanation thank you.
How does the heads made of aluminum effect the compression ratio capability?
Aluminum transfers heat out of the combustion chamber faster and more efficiently than cast iron. In a performance application this means aluminum is a little less prone to detonation if you compare two identical casings in the different materials. I’ve done this test before with World Products/Roush heads back 25-ish years ago. Same castings, same combination, different cylinder head material, aluminum made slightly less power (down 2-3hp) at the same timing and air fuel ratio. Aluminum tolerated about 2° more total timing though and because I could run that through the entire curve, the aluminum head hedged out the iron unit. If you’re building an iron head combination, shoot me an email with your planned usage and the specs and I can offer some advice to get the most out of it.
Hi Bart. Thanks for all the giudence. I really appreciate a lot. What do you think is a good oil pressure for a LS 2 stroker motor per 1000 rev's. Thanks Bart appreciate a lot. 😊
Who’s Bart? The old rule of thumb from the Smokey Yunick days was 10psi for every 1000rpm. Every application is different though. I’m building two 289 Fords. One a street / driver type build in the 325-350hp range that will turn a maximum of 6500rpm. The other is a more track oriented build in the 450-500hp range and will turn up to 7500rpm. The two builds use very different bearing clearances, and although they will run the same oil pumps they will run different oils as well. Hot oil pressure on both engines will be 60-70psi at peak rpm. Too much pressure is unnecessary and starts to cost you power.
@@TheGT350Garage I highly appreciate your support and advice 😊👍.Acording to you knowledge, Is it possible to bore a LS 6L aluminum block to 4.030.
Thanks appreciate.
So, I’m not an LS guru by any means. I know you can sleeve the aluminum blocks and go fairly large, but using the stock sleeve has some limitations. The LS1 and LS6 for example can’t be bored, they have to be sleeved. The iron 6.0L blocks can go 4.030 no problem. I have to defer this to the LS experts, like my friend Richard Holdener, I’m sure one of his videos cover this, and it’s certainly covered in his LS book. I really do surround myself with small block Fords in the garage, because at work I’m swimming in Toyota technology.
Hi Walter. I did upgrade my camshaft on my LS 408 stroker motor and make good hp. Normally all the dino sheets that I can find. The torque start higher than the hp then torque drops and hp take ower. Mine is different. Torque start high and keep on rising along with hp. What can be the reson?. Just interseting to know. Thanks appreciate all your time and guidence😊.
Torque start 379 to 517 at 4560rpm.
Hp start 147 to 523. (On wheels)
It sounds as if you have a cam that is spreading the curve out. That’s usually determined by the specs of the cam, and depending on your application it can be good or bad. I’ve long found a broad torque curve that spreads the power over a wider rpm range can be advantageous to a narrower torque curve with a higher peak. The broad curve is typically easier to drive, but requires a little more gear ratio and a willingness to let the engine sing. It would be interesting to see more complete details on your combination with cam specs and the dyno sheet, feel free to shoot me an email if you’d like to discuss it more.
Do you increase total timing after peak torque to compensate for lower cylinder pressure and less time available for a complete combustion cycle?
No. Because cylinder fill continues to increase to peak horsepower. Quite often peak torque happens at 10-15% lower volumetric efficiency than peak horsepower. As the volumetric efficiency increases so does cylinder fill and thus cylinder pressure. As cylinder fill increases you will often benefit from slightly less ignition timing than what makes peak torque.
Great video. Sub'd. I tune. Your info is on point!
Very good thank you . I’m a hobbyist to tell you where I’m coming from and a guy in a car club where there are also mostly guy hobbyists , but would like to ask you with your experience some questions as I have a 5 litre Windsor (roller cam )for the A model coupe and also I’m into air cooled vw ,on cam profiles, the stock roller cam looks good? Thanks
The stock 5.0L cam was just ok. Nothing special. It won’t really make much power unless you do a bunch of other work to the engine. Power is always determined by airflow, so the cam and stock 5.0L heads are a big determining factor for you. If you’re happy with around 250-260hp, that’s about the maximum that cam will support with those heads. Better heads like a 3-bar GT-40 iron head or would allow more power without a loss of drivability or idle quality.
@@TheGT350Garage cool thanks I see that some heads are also 4 bar , I don’t understand the terminology but also to let you know I will be putting a carburettor on and if you would know of a longer duration cam for street use I have a c4 transmission to go
The 4-bar heads make good power but have a revised spark plug angle that can be a challenge for header or exhaust manifold fitment.
@@TheGT350Garage thank you 😊
Im using 98RON here in Australia...350 sbc 10.5 compeession approx 500hp engine on dyno...I locked the timing out because it really likes it at 30° total...with the cam it has it wouldn't idle good under 16- 18° initial...i can double check that...and MSDs largest bushing is 18°....so my initial and mechanical was always 34-36 which i thought was the go to number. I have aluminum twisted wedge heads too.....now im at 30° and im keen to put it on the dyno to see the difference in power it makes compares to the higher timing numbers i was kinda forced to use....after seeing your video i was like wow until now i thought i was detuning it having it at 30 but it feels stronger than before.....my mates 383 made max power at 28 total locked out also.
Your engine really needs a vacuum advance distributor. It would take some stress off the starter and make it easier to crank with a lower current draw on the battery, and as soon as the engine builds manifold vacuum it would clean up the idle nicely. Your 30° total would be 12° initial with an 18° bushing and it would idle with 20-26° depending on the adjustment of the vacuum advance. At WOT the manifold vacuum advance goes away and you run strictly mechanical so you’re back to the optimal 30° under hard acceleration. What you’d see is an improvement in efficiency and drivability at part throttle and much easier starting, especially when the engine is up to temp.
@@TheGT350Garage Hi and thanks for the reply...actually it starts fine at any temps..has an aftermarket starter of some kind...but no kicking back or anything like that.
Im also using an 85551 pro billet distributor that cannot accept a vacuum advance canister.
Very useful information!! Can’t wait to see the next video….👌🏻
More to come!
Good video I have a big block chevy I have a 12.5 to one .I have a lock put Dist.and my timing is at 36 .iam going to try to get to 12.3 to compression ratio .Can I run 100 octane on that
You can run 100, but may not need it. It also depends on how you get to 12.3 or 12.5 with a BBC, open chambers and huge domes will need more timing than closed chambers with quench and small or no dome at all. The closed chamber is definitely the better way to go, it will have a faster chamber, require less timing, and actually work better with less octane required.
@@TheGT350Garage thank you for the infor
@@TheGT350Garage I using open chambers
Heads
what would be a good compression ratio for a 600 to 650 hp SBC 383 and cam profile on pump gas? looking at using AFR heads 220 or 227 cc and a holley super sniper and haing it controll the ignition. any thoughts?
EFI changes the game, it makes it much easier to hit the target air-fuel ratios. A typical 383 is a challenging combination, the rod/stroke ratio with a 5.7 rod is just 1.52, so it doesn’t have as much piston dwell time, that means it will need a little more ignition timing than a longer rod combo. Air fuel still needs to target the .86-.88 Lambda range. As far as compression, I wouldn’t hesitate to build a 12:1 or even 12.5:1 383. Do your research on the heads, it’s hard to go too big for what you’re asking, and don’t be afraid to leave the 23° heads for a 15° or something shallower.
A little fun math to calc a 650hp combo:
650hp is about 65lb/minute of air flow. 1lb of air is 13.33cu/ft. (65*13.33=866.5cfm)
866.5cfm * 1728 = 1,497,312cu-in/min /383cid * 2 (crank revolutions) =7818rpm at 100% VE. If you exceed 100% VE you can make the power at a lower rpm, but we’re talking a couple hundred rpm sooner, maybe 7200-7500rpm depending on how detail oriented the build is.
You’ll need BIG heads, you’ll need a BIG cam. I’d look into heads flowing in the 300cfm range at .400-.500” lift and cracking 350cfm at .700-.750 valve lift. Check out Eric Weingartner’s TH-cam channel for ideas on heads. Cam will need to be in the 255-265° range @.050” and near .700 lift to hit your goal. Of course the specific grind specs will make or break the build. Also, there are two ways to get 383” out of an SBC, the easy way, 4.030 bore and 3.75” stroke, or the better way 4.185 bore, 3.48” stroke. The bigger the bore, the better the heads will flow, the shorter 3.48” stroke with a 6.125 rod makes rod/stroke ratio a much more desirable 1.76:1 gaining back some of the torque lost to the shorter stroke.
Have fun:
I'm about to attempt 13.5:1 static with a GTX55 Nissan VK56 engine on ethanol. It has all the supporting mods and E85, we'll start with 15psi and creep north from there, engine revs to 9500rpm.
Thanks for the video, wish me luck haha
Cylinder pressure is cylinder pressure. As long as you don’t have unrealistic expectations about your timing numbers or Lambda/Air-Fuel Ratios I don’t see a problem here. At 13.5:1 static and 15psi you’re at 27:1, this is equivalent to 9:1 static with. 30psi. The difference is you’re going to create the same cylinder pressure with less air and fuel, which means it will be more efficient than the 9:1 combo would be. You’ll use less total air and fuel to make the same power in the same engine with more compression and less boost pressure. I’ve done this nearly 20 years ago with 2.0L Fords, not quite to this extent, but I transitioned from 8:1 with 15psi (286hp) to 10.5:1 with 12psi (338hp) in the same engine. To make over 50hp more from the higher compression combination was astonishing at the time, and clearly demonstrated that combustion efficiency was more important than airflow. I saw lower EGTs and was able to run slightly more timing to achieve the final output, and in both cases Lambda was about 0.78 at peak torque and 0.82 at peak power. Seriously, best of luck.
@TheGT350Garage thanks for your response! I had the same outlook with cylinder pressure having stuffed 60psi into my 2.2 4 banger for many years on 9.1, low timing figures around peak torque is always the way we tuned to make them live, but yes we'll be super cautious and depending on how it goes drop it a little if we need to, but comp is new to me and I'm excited to feel it!
In fact, given this has such high comp, we will tune it like it's a stock bottom end 4 cylinder and let the cubes do the work.
Read your spark plugs if you don't have any of the expensive tuning equipment. As for timing it doesn't really matter as far as an arbitrary number if the burn rate is faster less timing my set up likes more initial timing 14* and less overall 19* to 20* for a total of 34 to 36 at full advance. Read your plugs you can see clearly if your lean. If so set up your jetting one or two say from 68 to 70 primary and depending on if your running a 4150 carb with power valve secondary or not adjust jetting or PV.
Well id like to think i know a little myself. And what i know is ( i havent watched yet ) its better to run lower compression and more ignition timing. Now sure there a big amount of work that can help things work right like combustion chamber shape, cuts on the vavles port velocity cam timing, all play into helping things work better as in cr.vs octane. Look at the new (say 2016 and up) super bikes. They are 11- 1.minimum some are 12 so it can be done. But the biggest help in that area is digital efi more over a stand alone system that will alow you to make fuel ratio adjustment every 250 rpm as to where the factory ecu's allow a fuel adjustement at every 750 rpm and onviously ignition timing as well so that alone will alow you to run with a good chamber 11-1 the LT1 Chevy sb with water to the head first will run 11.7 to 1. with pump gas. But im always up.for learning more so lets see what the man says
.
The key thing to understand here is that timing itself is not what makes power, and more octane is not what makes power. Releasing the full energy content of the air-fuel charge and converting it into pressure is the goal, that’s more a matter of understanding the combustion cycle and the behavior of the air-fuel charge in the specific engine you’re working with. The timing still needs to be “correct” for the cycle, and the air-fuel charge needs to be the correct ratio to produce the energy required to reach a specific power output. Changing the temperature of the combustion chamber will allow more compression which will increase the temperature of the charge making it more reactive before you reach the point of auto ignition or allow more timing advance at the same compression ratio to increase pressure in the cylinder before causing spontaneous combustion elsewhere in the chamber which collides with the intentional combustion causing detonation. High compression has been used more and more in recent years but even with bikes, forms of variable valve timing are being used to manipulate the cylinder pressure. I’ll be sharing more information about high compression and camshaft timing soon.
In response to the 1st potion of your response. That is exactly what I said. To be more clear the design of the combustion chamber has more effect that anything when it comes to how much octane is needed..Also toluene does not increase octane. It was invented by the Renault F1 team back in the early 80's when they (F1 teams) were restricted to a 100mm inlet on the turbo and used a spec gas. Which I think was the unocal race gas. So by 83-84 they were making close to 1700hp.in Q trim and race tune at about 1450 - 1500hp from a 1.5 ltr. 4 cyl.. compression with 3 bar of boost static compression was 36:1 and higher toluene slowed the burn speed down and almost vanished spark knock forever Vp fuel C16 is 28% toluene. The F1 teams were restricted to 22% toluene is actually used as chemical flame retardant. Fireman suits.
@forcedinduction5245 you aren’t conveying cohesive thoughts in your comments, and a large part of what you’ve posted in this most recent comment is completely untrue. Toluene has been around for over 150 years, it was t “invented” by Renault. It’s not a magic elixir that cures all detonation even in high concentrations. 3-bar (4 atmospheres, or 45psi) resulting in a 36:1 static compression would mean a base compression of 9:1, but F1 (and Group B Rally Cars) we’re running in excess of 60psi. Of course combustion efficiency is key, but none of this has a damn thing to do with the purpose of this video.
I have my 302 stroker at 42 degrees. 10.5:1 compression, pump gas, car is light weight. When I took it back to 36 degrees, I lost a 1/10th in the 1/4m. Seems weird, your thoughts?
In my experience, you’re either dealing with an incorrect pointer and balancer relationship, or you are using a timing light that is misinterpreting your ignition timing. A lot (most) digital timing lights can’t handle multi-spark CD ignition outputs. The multi-spark output skews the timing light signal making it seem like the engine is tolerating more timing than it is actually operating at. I’ve been using the Pertronix Digital HP ignition more the past few years and with great success, and one of the key features I use on it is the ability to disable multi-spark for timing purposes. Now, it’s also possible your engine is not actually 10.5:1 and your cam may be bleeding off so much compression that you effectively have far less cylinder pressure than you think. Running a compression test correctly will tell you the engine’s pumping performance, and identify a cylinder pressure issue. Using an analog (old school) timing light can help you identify an issue from your ignition system. And finally, putting a piston stop in the no. 1 cylinder can help you ensure the timing pointer is truly reading TDC at TDC. The final caveat is that some cylinder heads (you don’t state what you’re using) have truly terrible combustion chambers, meaning they are inefficient and cause a “slower” burn rate leading to a need for more ignition timing. This is a common problem for D shaped wedge type chambers like FE Fords, but some Windsor heads (OE and Aftermarket) are affected by this chamber shape issue.
@@TheGT350Garage The pointer was checked. Old style ported Trick Flow heads. Compression test, with a cheap tester is about 185 and even. Cam is 231/239 @.050 and 110 LSA. And I just use a basic timing light. Ignition is just a Fast brand ready to run deal. No multi spark. Thnx
Ok, if you’re using old school High Ports, especially aluminum, then yes, you’re in the ball park, at 42°. Those heads have a rather slow chamber. I would caution you to be careful with the rate of advance, meaning don’t run an overly aggressive curve, bring in total at 2800-3200rpm, and use vacuum advance to improve idle and cruise efficiency and lower operating temps.
Twisted Wedge heads, be it a 15°/17° 170/185/205 head, a Twisted Wedge R, or the newer 11R series, have a much more efficient chamber and for your cylinder pressure on a 347 they would want 34-36° max, all in at 2600-3000.
It would be worth a couple hours on a dyno to set up the air fuel ratio and then optimize the ignition timing on the car at several points in the rpm band to find the ideal shape for the ignition timing curve your combination truly wants or needs.
I bumped a 5.2 magnum from 8.8:1 to 9.26:1...its now developed an appetite for 90 octane. You must meet the engines octane requirements..no if ands or buts..detonation will rapidly deconstruct your engine.
If you use the same ignition timing and air fuel ratio at 8.8 and 9.3 you’ll need about 1-2 additional octane points, or as you’ve observed an increase from 87-88 to 89-90. Your assessment that the engine requires the addition of more octane is because you have ignored both the air fuel ratio and the ignition timing in the OE fuel injection. Optimize the air fuel ratio and you’ll find the engine can return to the original octane rating by running at .84-.86 Lambda and you’ll also be within 1° of the original ignition timing. Making the same if not more power than you are on 90 octane with the lousy factory fuel and spark mapping.
@TheGT350Garage Not having access to high end tuning equipment leaves me kinda going old school. With success I'm happy to report..using live data to monitor o2 sensors and fuel trim led me to a lean condition. Plug reading confirms this..a small vacuum leak was repaired and colder 3923 plugs installed along with low ohm wires has me burning the rot gut again 😆
“High End” tuning equipment is not really necessary. You can’t rely on fuel trim data from a narrow range oxygen sensor though. They can only detect Lambda (Stoichiometry). If the sensor’s cut point for stoichiometry is .450v (450mv) any time you’re below that you’re lean and any time you’re above that you’re rich, but in either case you have absolutely no way to know how lean or how rich you actually are.
If your ECM was originally built with the assumption that the stoichiometric ratio of the fuel was 14.7, the sensor will perpetually give a lean signal to the ECM because modern ethanol blended fuel hovers in the 14.1-14.2 range. So your fuel trims will always show roughly +5%, or 5% lean, and if it’s an older (pre-2005 ecm it’s a challenge to interpret this). This is where you do need a wideband oxygen sensor and with kits in the $200 range now (they were $3000+ when I started tuning) it’s no longer a high end tool.
If you adjust the fuel pressure up or use a slightly larger injector (assuming it’s speed density and not mass air flow) you can get back to the correct air fuel ratio without needing to reprogram the ECM.
Whatever you do, you need to stop thinking it’s a fuel quality issue and realize it’s actually a simple adjustment to a slightly different stoichiometric ratio that’s needed.
Great video sir thoroughly enjoyed it. Makes a lot of sense
So do you run high dome pistons with a tighter squish in your high compression engines? Also does it help to add a little nitro? Thanks for the information 👍
I prefer to run a flat top with a small combustion chamber, but in the case of the 289 I’m building for the Shelby, there is a slight dome, about 0.060” on the piston. I’ve had the block machined to create a “zero” deck, meaning the pistons are flush with the deck and the domes in this case are above the deck. For most 289/302 builds this requires using the 8.190” blueprint specification from the 69-70 Boss 302 Trans Am engines.
Nitro(methane) is a volatile self oxygenated fuel and would have no place in a street engine. Nitrous oxide (another way of oxygenating you’d mixture m) on the other hand would love this combination and set up correctly you could add quite a lot to this type of combination, but laughing gas is like making wishes with the genie in the bottle, the first few times is usually fine, but eventually you get screwed over.
Brilliant, concise tutorial, thank you.
I am going to be running my 434sbc 63 nova on 11.04:1 SCR and 10.2:1DCR for the first time this year. It has 225 cranking pressure and probably needs a bigger cam. How worried should i be?
Back the timing off and push the a/f slightly rich, it will run fine. Do you need more cam? Yes, absolutely. At sea level the “ideal compression test pressure” from 11.04:1 is 227.2psi, ((14.7*11.04)*1.4) so you’re right there. Retarding the cam or adding more duration, both resulting in a later intake valve closing event, will allow some reversion at lower speeds to reduce the effective compression ratio, and producing less cylinder pressure. Ideally, 190-210psi is a manageable range to be in, so you’re not far off. If your cam is installed 4° advanced, simply moving the cam to 4° retarded would get you closer if not spot on in the ideal range, otherwise you’ll need a cam with 12-16° more duration @.050” to get the closing event optimized. Retarding the cam improves the idle, evens out torque production across the range, and shifts the power curve higher about 100-150rpm for every 2° you retard the cam.
real life useable information. Now what crank,pistons,and connecting rods are you going to use to get your 12.5:1. what will your qwench number be? head gasket thickness?
Getting 12.5:1 from a 289 is a challenge without using a big dome. My heads are TFS Twisted Wedge and they are being milled to bring the chambers down from 61cc to 46cc, a 2cc dome, the block is decked to 8.190” and I’m running 12.29:1. It’s not a combination for the faint of heart or those who don’t give tremendous attention to detail.
@@TheGT350Garage did you have to cut a lot off your intake to get things geometrically lined up?
No. Because I’m moving the port up the face of the head and away from the deck, the majority of the port alignment is addressed that way. I was able to leave the manifold it’s original width, elongating the bolt holes slightly inward for bolt alignment. Doing it this way also means no machining at the end rails on the valley. But, it’s A LOT of work and time to get everything matched up. Everything is done on the gasket faces, but even the water ports had to be addressed to prevent water leaks.
This is a ton of information, great video my question is where I’m located the octane rating is not provided how can I determine the octane cuz I want to run 12:1 compression
The fun thing about the internet is that with some effort you can find out a lot about things you didn’t think you could learn about. I would suggest talking to your local fuel stations to find out what refineries their fuel comes from. Chances are it is coming from a refinery that produces fuel for a known brand. At that point you can get an idea of what they are selling as regular or premium fuel.
Depending on your engine, it may simply be a matter of build the engine, target a Lambda value of about 0.85 (regardless of the fuel), and then do some testing to find the timing threshold for the engine. At the extreme of things, I’ve run 13:1 and used 87 octane in a DOHC 4-cylinder and it worked quite well, making over 100hp per liter measuring at the drive wheels.
@@TheGT350Garage thanks for your reply, gives me a good path to follow
?.. so i am tuning a 91 mustang eft using wide ban .. 357 . Now all guys say set ur target is 14.7 so whats ur opinion running 93 pump gas which all pump gas in 10% ethanol
If you can change the stoich point or reference Lambda in your wideband to 14.1 and tune in Lambda for - target of .86-.88 Lambda you’ll be on the money. With pump gas your target under load results in a 12.1-12.4 A/F on E10 premium. You can run a little leaner past peak torque but timing will be more and more critical as you pass .90 Lambda or 12.7:1. Timing should decrease about 1-2° per 1000rpm above peak torque, which means you’ll be 3-4° less than what makes peak torque at peak horsepower. If peak torque comes from 33-34°, peak horsepower will come from 30-32° in a typical SBF running 9:1 to 10:1 compression with a decent cam and aluminum heads.
Great video and makes perfect sense. I've often thought that setting timing crazy is going to make a bomb. I'd be curious to see what compression ratios are of 9.1 under 20 pounds of boost.
So atmospheres pressure is 14.7psi at sea level. If you add 20psi, it’s 34.95psi acting n the engine. That’s 2.35 atmospheres, so you multiply the static compression ratio by the atmospheres meaning 9.1 Compression is the equivalent to about 21.4:1 at 20psi manifold pressure. That’s a big number but it will still run on pump gas with EFI.
Timing is everything.
Most people need viduals illustrations that show what you're talkin about, honestly I didn't glean much from this
I’m working on better illustrations and probably going to get a white board.
I have a 302 with flat top pistons and .035 quench, 58cc chamber. I used a compression calculator that said 9.9:1. dynamic, with stock GT cam, said 7.4 . I run 87 regular and cannot hardly make it ping....but the car weighs 2850 and has a 3.25 gear. So, would advancing the cam give more dynamic compression like the calculator says? My heads are already milled .040 to get here, so there is nothing left to increase in the static dept.
Dynamic compression is not the end-all be-all answer to detonation, octane needs or engine tuning. It has very little to do with it actually. At 9.9:1 your engine should have a cranking compression test value in the 175-185psi range, especially if by stock GT cam you mean a 5.0L HO roller cam. Advancing the cam from the stock 115° ICL to say 107° ICL will alter the power curve but have minimal effect on the cranking compression, it might go up 5-10psi at most. The problem is it doesn’t change the overlap and therefore doesn’t benefit the engine much.
If you study camshaft events thoroughly enough you’ll be able to make an argument for the importance of EVERY individual cam timing aspect, EVO, ECL, IVO, LSA / Overlap, EVC, ICL, and IVC. And each one has important roles, advantages, disadvantages, and reasons why you will or won’t do a particular thing with them, or you’ll fight to get a particular number for one or more of them.
Dynamic compression focuses on IVC like it’s the secret to utilizing high compression, BUT I can argue that LSA and Overlap have a greater effect on compression than when the intake valve closes, that IVC is perhaps even irrelevant in terms of “compression”.
My suggestion is a different camshaft will produce better results than altering the installed relationship to the crankshaft. If it’s a roller motor, going from a stock HO cam to an old school X303 installed “way out” at 113° ICL would net solid gains and retain you 87 octane compatibility. That is, if you have the room.
@@TheGT350Garage You make an excellent point in that closing the intake valve sooner at the expense of moving overlap events away from TDC may not increase captured air volume at all....if I understand you correctly. I have been studying this for a couple years, but lack real experience. The engine referenced above was done with a budget of 1200 bucks, for the purpose trying to understand the process well enough that if I ever put real money into it, I would spend it correctly. Actually, I notched the pistons and checked the clearance before final assembly, and had .100 on the exhaust and intake. I dont know if the piston liked what I did to them, but I have put 1500 miles on it and run it hard at least once everytime I drive it. I will leave it alone for now.....eventually I will pull the heads and grind a little more on them and give the intake valves a 30* cut back. lol...my cylinder head tech dept. got better since. I will keep my eyes open for a x303. Thanks for your reply.
I've got a 67 fastback I run a 289 with race tech dome Pistons and 58cc aluminum heads, mechanical cam. It runs good pulls hard to 7500 rpm. I can tell you this 91 pump gas 10% alcohol sucks In the summer at 5000ft it boils in the carb. When I mix it 50% and 40% pure gas and then 10% VP leaded race fuel and it makes all the difference in the world in drivability.
Altitude lowers the pressure which in turn lowers the boiling point of the ethanol. It’s a challenge. Have you considered using a heat barrier gasket like an Edelbrock 9265 or 9266. They are based on the gaskets used to separate the heat of the EGR spacer from the carburetor on emissions engines and do a good job of reducing carb temps. Another possibility is to install a return line and fuel pressure regulator (similar to early EFI systems) and put a cooler in the circuit to reduce the temperature of the fuel. I’m at 4500ft and these are things I’ve done in the past for operation at altitude.
@@TheGT350Garage
All good Ideas what I have done is run a spacer between intake and carb also have a cobra jet scoop but it gets over 100* here and a black hood doesn't help even with heat extractors. 100% gas works the best ,for me. Also Aluminum heads allow for higher compression I run my 289 hard close ratio Top loader Detroit locker and 4:11 it's got just enough gear to be quick, smoke a lot of homies. I built the this pretty much like a 65 gt 350 all suspension mods hotter 289 but it's been fun for 41 years I've had it since I was 14yrs old.
Sounds like a really fun combination. The key to stopping the ethanol from boiling out of the fuel will be pressure and temperature control, which are hard to do in a fuel bowl. Short of keeping the fuel under pressure using fuel injection all you can do is seek out clear gas (ethanol free). We have 91 octane ethanol free at a couple locations here in northern Utah.
I the weekends i Work in a scooter shop.when customers put 10 percent ethanol mixture in these 4 stroke scooters. The combustion chamber and valves will cake up and will not close 100 percent and compressie willen drop.without the ethanol mixture there is no problem on tesame kilometers
Sounds like a localized fuel problem or an issue with the crankcase ventilation design on the engines.
Softening the quench area helps to decrease spark Knock(detonation)
I agree with softening but not “slowing” the chamber. I’ve applied the principles of the “soft head” and “groove theory” in building engines over the past 20+ years, and both when applied correctly work very well, but both require a rather tight quench area and a small combustion chamber to be most effective. For the average enthusiast, simply detailing the combustion chambers to remove any sharp edges is an important and easy step to pull the most out of the chamber, a basic softening technique. Even CNC machined heads benefit from a light touch with some abrasive, be it hand finishing with 400 grit paper, or like I do with Scotch Brite pad in a mandrel on a die grinder.
I have an 11:1 4.3 v6 chevy...my initial timing is 8 degrees/total @20, so as to stop pinging....using 110 race gas...should I shorten initial timing?
You shouldn’t need race gas at 11:1 compression. Before I can comment on timing setup, I need more information about the engine combination.
Head info: Ported? Open or closed chambers?
Piston info: Flat top or dome?
Cam info: Int/Exh Adv. & .050” duration? Lift? Installed Lobe Centerline? Lobe separation angle?
Carb? Intake? Headers? Exhaust?
Cranking Compression?
If you can fill in all or most of those blanks, I’m happy to give you an idea of what’s going on and how to approach it.
@@TheGT350Garage....has knuckle top pistons,stock iron heads,valve sizes stock, w/exhaust opened to 350 sizing, and intake hydr cam specs unknown.Has 1.5" ceramic headers,480 QFT carb, pro billet dist....roller rockers 1.5 ratio,6 qt oil pan....now using 12 deg initial and 28 total timing with approx98 octane mix....though I am diluting out the 110 race gas to arrive at trying only 93 octane as I tighten up the total timing to avoid pinging
???
Your combination sounds like it might need more cam. What is the cylinder pressure during a compression test?
Thank you for this really helped with my drz build
8 to 1 was never considered high compression from 64 to 74. What do you call 11 to 1 like the 1970 Chevelle SS?
You’re missing the context that compared to engines prior to WWII, an 8:1 compression ratio was relatively high compression at the time, wether it was considered high compression or not in period wasn’t the point, it was a substantial increase from the previous generation of engines.
The development of high octane fuels after WWII allowed us to build what we consider truly high compression ratios of 10.0:1 and greater like the Chevelle SS you’re referring to. And in modern context, 10.0-12.5 compression ratios are not really “high compression” anymore, they’re quite common actually.
I have a new video coming where I’ll get very specific about compression and cylinder pressure.
@@TheGT350Garage If you had said WWII instead of 64-74. I would not have left a comment.
@blackericdenice directly from the transcript: “By modern standards, high compression is any engine with a static compression ratio over 10:1, but prior to the Muscle Car era (from 1964-1974), 8:1 compression was considered high compression.”
“Prior to” not during the Muscle Car Era of ‘64-72.
I appreciate your comment.
Great info. Thank you!
You're going to have to correct something you said high compression ratios were from 66 to 1970 as much as 12 to 1 compression, then from 71 to 74 they were considered smog motors and lowered the compression to 10 2 to 1
‘72 was the year compression ratios dropped, not ‘71. There were still a few hold outs that got through into ‘73, not many, but ‘71 was still a good year for factory muscle cars.
I'll run E85 and not worry about it! I only deal in WOT anyway.
Fools and their money are easily parted. E85 is a joke, and the joke is on people like yourself who think it’s better than pump 91-93. The garbage they call E85 from the pump is wildly inconsistent and has to be tested tank load to tank load due to wild variations in ethanol content. Canned E85 is expensive enough you may as well run proper racing fuel. And if you’re only running WOT, you probably have a 12-15 second attention span so I doubt you grasped the concepts presented in this video.
Awesome video keep them comming
You referenced specific heat while calculating compression and dynamic compression at 1.4. What is the specific heat of the compound you are refering to? just googled gasoline and its 2.2+/- so is it the combination of gasoline and air at stoic? Thanks for bringing up lambda because its really the best way to look at fuel use and need of every individual engine. Two exact cars with exact builds will vary (maybe only slightly) but that slight difference can show discernable characteristics that each engine has (quote unquote identical builds), ergo the differences in necessary adjustments for optimal desired function.
I’m in the middle of a 6.4 hemi (2016 scatpack) build . Building a 426 stroker 9.51:1 static for turbo boost. I’m talking 3650 ish street car and try to run it on pumpgas too.. (planning on a second “track “tune . Maybe with a second gastank and bigger pump too) . I’m a the point to choose a cam for this build . Maybe you can shine some light here? What are the limits to run this on 91 or 93 pumpgas ? If I would have 750 hp ish at the crank for the street, will be more than enough..
Thanks from the Netherlands 🇳🇱
Denny
Your power goal puts you in an unusual situation. A 426” 3rd Gen Hemi? Build it N/A. Let it make power. Push the compression up to 12:1 and get a cam in there that will unleash the full potential of the engine. It should be able to push 650+hp at that displacement from the parts available for that engine, then put some gear in it and turn it loose. The simplicity of a big displacement N/A build is hard to beat.
The turbo route is fine, but you’re adding complication and weight, generating and retaining more heat, and for little more than an extra 100hp over a legit NA build. You ultimately have to sacrifice efficiency and power to be in the 750hp range and you’ll have a challenge getting a single turbo to work well at relatively low boost (6-8psi for your power goals on that engine), smaller twins would perform better but add further complication. Cam selection will be critical (and on the small and conservative side) because it has to balance cylinder pressure with exhaust drive pressure to get the turbo to respond, and not cap the power potential simultaneously, or produce too much cylinder pressure and create a fuel octane sensitive monster.
My advice would be dial back the power goal slightly and build a proper 650+hp N/A combination, or up the power goal to 900-1000hp and build a proper turbo engine, which will ultimately cost little more than the 750hp you want.
Sorry for the late response…., just this morning I noticed the push message .
I know the turbo route isn’t the easy way, but it’s on my mind for a long time. It will be something different, not many are around back here, I’ve never seen one.
I could go up in power goal, let’s say 900at the crank. But what gas would I need ?
( we don’t have E85 at the pump)
And how about dynamic compression ratio and effective compression ratio in relation to the gas I would need to run ?
Because you’re right.., the last thing I want to do is turn this build into a fuel octane sensitive monster…
@@hemi-denny set the compression ratio and n the engine at 9:1 to 10:1, and target 500-550hp, build it with parts hood for 1000hp. 7-8psi will net you around 800hp, 14-15psi will put you at close to 1000. All of that is attainable on AKI 91-93 octane, 95-98 RON. You’ll just need to be careful with the air fuel ratio (target 11.2-11.5:1) and bring the timing in gradually, you’ll need to install an EGT on each bank and watch your temps to make sure you advance the timing enough to keep the the exhaust temps from damaging exhaust valves or the turbine side of the turbocharger(s). With the slower nature of a Hemi combustion chamber and the compression and plboost range you’re targeting, I suspect you’ll need 23-26° of timing.
@@TheGT350Garage For some reason it takes 10 days before I get your reply…. ,so again sorry for the late response. I appreciate your help and information a LOT !!
The plan I have in mind is to put a single turbo underneath the car at the spot where the muffler use to sit( in front of the rear axle) . And at the other side a water cooled Intercooler (no mufflers at all in mind). I have TTI ceramic coated 2” headers and plan on heatwrap the exhaust and Y pipe underneath the car . How about if I stick to the stock (smaller) Scatpack cam ? For better spool ? Stock (Scatpack) cam 215/221@.50 and can be advanced 14 degrees, from what I have red.
Really looking forward to your opinion about this..
Thanks again
@@TheGT350Garage
I forgot to mention the LSA of the cam ( 121 , again from what I red on a challenger forum)
Probably some additional info about the short block/stroker kit will help too.
Bore is : 4.10”
Stroke : 4,050”
Rod length: 6,125”
C.R. : 9:51
All forged internals , hope this helps too to get a better picture of what I’m trying to do.
Very informative and helpful video .thank u sir!
Good info! Thanks!