I built a small block ford and used the flow bench plans from one of Davids books. Not been to the track but with a stock valve size and a 288 duration cam the thing has an overwhelming amount of torque. My hot rodder friends can't believe its just a stock ported headed engine.
Hello. Which book had the flow bench plans in it? The book he wrote about porting and flowing? I have a Super Flow 110 and have used for quite some years and was wanting to build the bench I saw him describe. Was it the bench with the manometer through the spark plug hole?
David's cam spec formula is dead on if..... you're ultimate goal is to produce the MOST POWER possible. It does not factor in "driveability" or "street manners" or "MPG" or "idle quality".. if none of those factors are of concern to you then,.... USE THE FORMULA !! I sure as hell am. 👍
Met David at SEMA in 1985. First article I read in a magazine of his was titled The 97 HP exhaust system. Have most of his articles and books. If a new idea or motor comes out sooner or later he will write a good engineering break down.
Very great information thank you! I see a lot of folks who claim if you have EFI then you need much larger lobe separation angle, which I don't undertand. After all, your video about the Ford cams was enlightening and those cams are for EFI 5.0/351 engines, and the same LSA principals apply, right?
I built my first Ford 302 years ago using David's book with a moderate flat-tappet cam and porting the horrible stock heads with his methods and it ran strongly considering the combination. Ran it for 10 years and then built another no-expense barred 302 with a bigger hydraulic roller cam, AFR heads, etc. It made about a 50 hp difference but never really seemed to be making what it should have relative to the parts installed. The cam had longer duration and more lift but...because of air-care testing getting more stringent, I opted for a 112 CA instead of the 110 CA of the old motor cam. For fun, I ran the numbers through this formula of my current motor and guess what the number was: 110. I think I'll be going back to a 110 CA on my next build!
When I read a book you had, I understood and agreed with everything you said, I understood. Now I have a stack of your work, I have used it without fail for years. I had retired. Now I am going to help my son with a turbo ls engine. I am anxious because I will make the ls engine fly. They are remarkable. I would like to hear what you have to say about them
The formula is right on and on my daily driven turbo gm v6 it’s got excellent cold start and idle character and despite being a cheap backyard build it’s actually considerably faster than friends with much bigger cams and much more money spent/wasted
Question: How to adjust the formula for 50 deg valve seat angles? The presentation says that there’s an assumption of a certain amount of flow right off the seat that’s based upon the valve diameter, but a 50 deg seat angle acts like a smaller valve off the seat and a bigger one at higher lifts; is there an adjustment one can make to the formula for 50 deg seat angles?
You do the equation like this. Math rule is do math in parenteses first. Ex. 350div.by 8, hit equals, div, that number by valve size, hit equals, times that by .91 hit equals , then subtract 128 from it ! Should be 108.29 if you have a 2.02 valve !
Mr.Vizard you are a God send . So much great information. On your formula for correct intake duration the number you get from that is that advertised or .020 Thank you !!!
David thank you for all your work and research but mostly for sharing your knowledge do you offer a cam selection service. Im building a street strip cleveland 4v with approximately 10.5:1 and ive heard that the cleveland uses a different starting number 132 instead of 128 if your able, thank you. Bobby Essick
I just use that chart in the book man the one on page 107, somewhere in the back it talks about widening or lowering LCA for rocker ratios somewhere for compression ratios. Finding a catalog cam that matches what I need isn’t always easy for me though. I can always get pretty close. I don’t feel as if I ever outright miss on a camshaft. I even tell people where I got my information. My buddy thinks I got some voodoo or whatever. It’s printed in a book, that anybody can buy. Also I built the flowbench from page 74. Because we have a build where we have to make the best of what we have. Time to see what I have really learned over the last 25 years of reading your stuff. I am just such a huge fan of yours. I didn’t even know you had this channel.
Would really like to buy your CD for choosing cams, looking for a leg up on building the LS platforms & even Big block Chevy. You have helped me a ton on our sbc builds. Will your CD help our LS & BBC builds? Looking for maximum TQ in the midrange for heavy 4wd rigs. Thanks
Mr. Vizard, great stuff buddy. Thank you for all the free info and experience. I started reading a bunch of your stuff as soon as I saw the Budget Sledgehammer build (which I'm going to build real soon). I have one question for you though; is your 128 formula applicable to fuel injected engines? Most of the stuff online agrees that to run any fuel injection (aftermarket or stock) efficiently you need a wider LSA. Thank you for the reply if you have the time.
It's not just interet lore; check out the LSA on factory cams used on the same engines that were carb'd and later EFI. The EFI cams all went to a wider LSA than their Carb'd predecessors. "Chuck Lawrence (John Kasse Racing Engines) received the order to bestow a 520cu in big-block Ford with the sound of a Pro Stock engine, he replaced the normal 112LSA hydraulic roller cam with one of 108LSA. “The result sounded wonderful,” said Lawrence, “but it didn’t rev as enthusiastically and it made 30hp less than normal!”
you can tighten the lsa up a lot compared to factory efi cams. factory cam are very wide. It comes down to how much valve overlap you have and you may have to bump up your idle speed. But vizard talks a lot about making big power with very conservative cams for street engines
Look at the stock cam for the TBI 305/350. That cam specs out at 179/194 @.050 on 109 LSA. These same engines can run an Iskendarian mile-a-mor cam spec'd at 194/194 with 108 LSA or a Melling 184/194 with 104 LSA and the TBI 350 is a speed-density system. Granted, modifying the TBI to have 2-inch bores, better FPR internal spring(18 psi) and installing a fuel pressure gauge will help the TBI setup run better
I would like to implement this formula on a Buick 455, but I always run into a couple issues. First, for a street engine, the overlap quickly gets out of hand for running power brakes with the required 103 centerline. The other issue is that the dynamic compression with iron heads that is safe for pump gas is a problem with the narrow lsa. It requires 9.5:1 or less static compression, and the average build using the available dished pistons comes in at 10.25:1 at zero deck with good sqish. I believe that is one of the reasons many use a 112 LSA. The only solution for both problems is to increase the LSA, but this is not good by Mr. Vizard. What is the solution, or is it just a compromise?
Hi. I have a 1970 Ford 351 Cleveland 4V head engine with the canted valve heads. Would I use the 128 formula for it ? Also my engine has 10.25:1 compression. The side cant on the exhaust valve is 3 degrees. The intake valve side cant is 4 degree 15 minutes. The valve angle for both valves is 9 degree 30 minutes. Thank you for your info.
My 2nd to last 4WD was an Australian release TRD Hilux 4000SL. I knew that engine/blower combination was special from when I drove it out of the showroom. Just did the math and worked out to 1.384 ft/lb per cu/in for a “stock” engine. I understand this has the blower on top too which obviously bloats the numbers but a really under appreciated engine as it was released right at the time of the GFC. Nobody wanted to spend the $$ for one
I got your book and ive tried a few things and it works great! I want to have a cam made but when i use your duration calculation i get 276 . Does that 276 mean advertised duration or at a certain check height? The book never tells you
That's division. 10.5 to 1 is compression ratio. Divide CID by 8 then divide what you get by valve diameter, then multiply what you get by 0.91 then calculate 128 - ANSWER. This channel is dead for now, find his other channel called David Vizard.
Could you do a video on how to calculate what camshaft to use for the rpm chosen. Im still confused on your methods. Thank you for your immense knowledge you share with us.
@@jrjohn1335 but that doesn't answer the question. That just tells them to spend a bunch of money and plug in numbers into the software. You're not going to learn how to spec a cam for a specific engine like that. Then again, this is one of the main issues at ST. Everyone will tell you what to use and how to spend thousands upon thousands of dollars but not how THEY spec cams. Instead, they'll tell you that you need to redo your entire powerplant and then question everything you tell them about it as if you're lying about it all.
Hi david, i have a engine motorcycle 250cc with a rod length of 103,5mm and 65mm stroke, piston 70mm , valve diameter 33 in intake, how i use that formula to calculate the LCA for making me camshaft, its engine for dragracing 250meters! Thank you
That formula won't work for what you're wanting. Your engine has about 1/3 the cylinder volume of the engine style that equation is made for. A smallblock Chevy has a cylinder volume of about 43.75 cubic inches or almost 750cc. Your 250cc bike's cylinder volume is closer to 15 cubic inches. Around 1/3 the size. There's no way that equation could possibly be used to spec even a somewhat usable camshaft for your bike. Understand that David derived this equation from thousands upon thousands of dyno tests and the info he collected from those smallblock Chevy V8's. To formulate something like that for a 250cc bike engine, he'd likely need the same sort of info. Thousands upon thousands of results to sort through to look for patterns, etc... The only thing that may be somewhat comparable would be if he had something like this for 'Mini' engines aka Mini Coopers, etc...because I would expect them to have small enough engines that it could possibly be comparable.
Mr. Vizard, You wrote a book back in the day on tuning Triumph engines. In regards to the 2L inline six (GT6) would the 128 cam formula apply to this particular engines. My calculations indicate that a LCA of 114 + would be the angle on this motor, however in the Triumph cams the LCA of 110 is what is available. please let me know what you think
I've always been under the impression that It applies only to Small Block Chevrolet V8 engines. Ford smallblock use a different number, 127, and Big Block Chevrolet engines use a 3rd number, 133.5, that's different from each of the previous numbers. Fairly certain those are all correct. I also seem to remember there being a number, 132, used also. That likely could have been for the BBC, then David modified the equation for better accuracy by using 133.5
Can we talk gas mileage ?? I already had a 7 MPG Camaro. I'm building a "83 Firebird lightened to 3,100 pounds with a 350, 700R4, 3.23 gears. I have single and dual-plane Edelbrocks, several Holley, Rochester and Edelbrock carbs, a "Fluidampr" and flat-tops. I need cam specs and head choice. Compression should be under 10.5 - going for a fun street sleeper as the car isn't in good paint. Was thinking shorty headers, but unfortunately dual exhaust doesn't fit well under these cars. Currently log exhaust to stock muffler. I believe gas will go back up to $5.00/gal so crazy, lumpy cams are out of the question. - - Previously - - I built a roller 305 Firebird that got 28 MPG highway with a leaned-out Rochester and mostly "stock" set-up. Suggestions ??
Yep, his book has been out for years and cam customers like me always ask for the specs that he promotes (and has the HP figures to back them up) and they have come around to his way of thinking. Even GM uses him.
@@PerformanceEngines I used Jones Cam Designs. I have never seen anyone have a single bad thing to say about his cams, especially for the typical sbc. I don't even pretend to know what the basics of cam design are, but I do have enough sense to contact an expert to get me the result I'm looking for.
This is a very narrow window formula for specific apps. It DOES NOT apply across all 4stroke engines. Not even all small block chevrolets. Edit:for what it is designed for, it is nearly spot on, but even David will tell you this is for a specific application.
OK, I'm a noob, so be kind: I know what LSA is [Lobe Separation Angle], but what's LCA? Same thing by another name, or some other critter entirely? I'll keep watching to see if the explanation is forthcoming, but I just had to pause & ask when I read the formula... OK, it was: "Lobe Centerline Angle." Still don't know how that relates to LSA, but will continue watching & learning & who knows, it may yet be revealed! Thank you Mr. Vizard!
Lobe Separation Angle is the number of cam degrees between the intake and exhaust lobes. Lobe Center Angle is the angle in crankshaft degrees of THAT particular lobe in relation to top dead center of the engine for that cylinder being measured.
LCA is LOBE CENTERLINE ANGLE . LSA is the distance between lobe centerlines at centerline of the top of the lobes not necessarily exacting peak. So the more lift for a cam with the same centerline angle, the cam can grow in lsa without anything else being changed in design but lift.. But this does not happen because of the lift to duration ratios are always close enough to hardly change by merely changing lift to duration, although can be adjusted any way by different lift and duration ranges.
LSA, lobe separation angle, is ground into the cam. It's Permanent. LCA, lobe centerline angle, can be changed through indexing the cam when degreeing it in. They're not the same thing.
David this is alil over my head. I watched twice & tried to keep up but I have to many questions in the beginning that you leave me behind. Although this is exactly what im interested in! I love the math & the science involved in engines! I've self tought over the yrs kinda, dont want to not give credit to those that have takin me in & helped me but what I mean i dont have a single person that has always been involved in engines that was close to me therfore I was always around engines. No, I just simply had a overwhelming interest so I would seek out information. I would get two respectable mechanics & one would tell me how chevy is clearly the best & well, fords are junk. But another, equally respectable, would tell me he likes fords & dont listen to that crap. Witch drove my curiosity even more! I wanted to know if one was better & why it was better & why people that literly work inside these engines could give such different answeres. Anyway sorry about the long speech. I know more than alot of people that work with cars & least around here, but im not up to this speed yet. Can you help me learn this or point me in the direction that can help me understand more. This is not how I make my living, this is just my hobby. But I make my living to support my hobby, its my passion!
Hey Jesse, I read your comments and it’s struck a chord with me in a similar way about the fascination of engines and all that makes them tick. I guess a was lucky to have my late father help me when I got my first dirt bike at 5yrs old and pretty much said “I’ll show you the first time, then next you’ll fix it”. That’s how I got started which I’m very grateful, and then onto diesel mechanic, but I’ve found from a lot of great channels like David’s but in more layman terms to help build the foundation which I’ll admit, I’ve learned bloody heaps haha. Do you follow many other car people or engine building channels on TH-cam? Let me know mate and I might be able suggest a few you may like that could help. Cheers mate. Jim😄✌️
This formula does not make mathematical sense! A valve is a circle, and the area of a circle is achieved using the formula π*r², this formula uses the diameter of the circle, but increasing the diameter of a circle by 5% increases it's area by ~10%! This formula may work for a specific valve diameter, but it cannot possibly work for all valve diameters!
I'm sorry I'm very sure patients when it comes to watching videos if you have information to put out just put out all this other needless to know information just makes me want to pull my hair out. And like I said Dyno results speak just place them up and the results speak for themselves
Dave Lang said you're good at one thing... selling your stuff. By the lack of response in this comment section I take it your information is indeed _not free._
AND WHO EXACTLY IS DAVE LANG? THE FACT YOU ARE WATCHING THIS INFO FOR FREE WHICH COST ME A SMALL FORTUNE TO GET SORT OF CONTRADICTS DAVE LANG DOES IT NOT? BUT THAT ASIDE I HAVE SPENT OVER A MILLION BUCKS ON RESEARCH IN THE LAST 50 YEARS. COULD YOU EXPLAIN TO ME IN VERY SIMPLE TERMS WHY I SHOULD JUST UP AND GIVE IT AWAY???? WITH MAYBE A QUARTER OF A MILL INVESTED IN GETTING THE KNOWLEDGE REQUIRED DO YOU THINK YOUR DOCTOR SHOULD TREAT OR GIVE YOU THAT KNOWLEDGE FOR NOTHING?
@@marvingvx1 thank you sir , I my self have learned a lot from your books and articles over the years and I would have paid much much more than what you charged. Thank you again for your hard work and dedication and I look forward to learning more from you.
I have been reading his articles and books for many years. For a price not too far north of 'free' I have been rewarded with a treasure trove of useful information. Every time I have put that information to the test, I have found that the result spoke for itself.
@@marvingvx1 there will always be those that want something for nothing. Pay them no mind. I have a few of your books, and have found them invaluable in my quest for more sbc horsepower. Thank you sir for posting these videos and little tidbits of tech info for free. I think I speak for the masses when I say. Thank you!
When I read a book you had, I understood and agreed with everything you said, I understood. Now I have a stack of your work, I have used it without fail for years. I had retired. Now I am going to help my son with a turbo ls engine. I am anxious because I will make the ls engine fly. They are remarkable. I would like to hear what you have to say about them
![SAFEPLANET - ดาวเคราะห์ [ THE PLANET ]](http://i.ytimg.com/vi/4X1XL3I_k3c/mqdefault.jpg)
I have no idea how i ended up on this channel but damn has it helped, i went from amateur mechanic to a good tuner in months.. thanks david
I'm just stoked they uploaded these 1980's videos to the internet
I built a small block ford and used the flow bench plans from one of Davids books. Not been to the track but with a stock valve size and a 288 duration cam the thing has an overwhelming amount of torque. My hot rodder friends can't believe its just a stock ported headed engine.
Hello. Which book had the flow bench plans in it? The book he wrote about porting and flowing? I have a Super Flow 110 and have used for quite some years and was wanting to build the bench I saw him describe. Was it the bench with the manometer through the spark plug hole?
David's cam spec formula is dead on if..... you're ultimate goal is to produce the MOST POWER possible. It does not factor in "driveability" or "street manners" or "MPG" or "idle quality".. if none of those factors are of concern to you then,.... USE THE FORMULA !! I sure as hell am. 👍
David Vizard The ROCKET scientist of internal combustion. Truth
a tip: you can watch movies at Flixzone. Me and my gf have been using them for watching loads of movies these days.
@Odin Franklin Yea, have been watching on flixzone} for since november myself =)
Met David at SEMA in 1985. First article I read in a magazine of his was titled The 97 HP exhaust system. Have most of his articles and books. If a new idea or motor comes out sooner or later he will write a good engineering break down.
I buy your books and used your advice with my first ever cam swap. And it was successful no doubt.
Very great information thank you! I see a lot of folks who claim if you have EFI then you need much larger lobe separation angle, which I don't undertand. After all, your video about the Ford cams was enlightening and those cams are for EFI 5.0/351 engines, and the same LSA principals apply, right?
What formula can be applied to 4 cylinder engines for best LSA?
I built my first Ford 302 years ago using David's book with a moderate flat-tappet cam and porting the horrible stock heads with his methods and it ran strongly considering the combination. Ran it for 10 years and then built another no-expense barred 302 with a bigger hydraulic roller cam, AFR heads, etc. It made about a 50 hp difference but never really seemed to be making what it should have relative to the parts installed. The cam had longer duration and more lift but...because of air-care testing getting more stringent, I opted for a 112 CA instead of the 110 CA of the old motor cam. For fun, I ran the numbers through this formula of my current motor and guess what the number was: 110. I think I'll be going back to a 110 CA on my next build!
What number is used for a hemi? 133?
Does the .91 have anything to do with the throat percentage?
When I read a book you had, I understood and agreed with everything you said, I understood. Now I have a stack of your work, I have used it without fail for years. I had retired. Now I am going to help my son with a turbo ls engine. I am anxious because I will make the ls engine fly. They are remarkable. I would like to hear what you have to say about them
can you tell me how to use the formula when the compression ratio is different than 10.5?
The formula is right on and on my daily driven turbo gm v6 it’s got excellent cold start and idle character and despite being a cheap backyard build it’s actually considerably faster than friends with much bigger cams and much more money spent/wasted
Question: How to adjust the formula for 50 deg valve seat angles? The presentation says that there’s an assumption of a certain amount of flow right off the seat that’s based upon the valve diameter, but a 50 deg seat angle acts like a smaller valve off the seat and a bigger one at higher lifts; is there an adjustment one can make to the formula for 50 deg seat angles?
What would the formula be for a 572 Gen2 Hemi?
Just on the dyno:
355ci sbc
9:1 compression
Trick flow 175 dhc heads
Isky 258/262 208/208 @0.050
.464/.464 lift w/1.6 roller rockers
107 lsa with 4 degree advance
400 ft/lb @4200
360 hp @5100
16" vacuum @800 rpm
15° initial timing 34° total
You do the equation like this. Math rule is do math in parenteses first. Ex. 350div.by 8, hit equals, div, that number by valve size, hit equals, times that by .91 hit equals , then subtract 128 from it ! Should be 108.29 if you have a 2.02 valve !
BODMAS: Brackets, Orders (squares, cubed etc), Division, Multiplication, Addition and finally Subtraction.
A priceless essential in life!
I would like to know how to adjust this formula for different valve angles.
Mr.Vizard you are a God send . So much great information.
On your formula for correct intake duration the number you get from that is that advertised or .020 Thank you !!!
How to get 2.0 lb ft/cube ? Build an engine to D.V. spec and then put a Tuned Port intake manifold on it.
David thank you for all your work and research but mostly for sharing your knowledge do you offer a cam selection service. Im building a street strip cleveland 4v with approximately 10.5:1 and ive heard that the cleveland uses a different starting number 132 instead of 128
if your able, thank you.
Bobby Essick
What is the difference between lobe separation angle and lobe center line?
Is there a list of camshaft manufacturers who can grind a camshaft with a narrower LSA based on David's data?
I have a question regarding overlap. At what valve lift are you calculating opening and closing events?
I hear that you have an extensive camshaft selection program how can I contact you for a camshaft for my engine thanks.
Vizard the engine wizard!
Do you have a formula for 4 cylinder single cam pushrod engines?
I just use that chart in the book man the one on page 107, somewhere in the back it talks about widening or lowering LCA for rocker ratios somewhere for compression ratios. Finding a catalog cam that matches what I need isn’t always easy for me though. I can always get pretty close. I don’t feel as if I ever outright miss on a camshaft. I even tell people where I got my information. My buddy thinks I got some voodoo or whatever. It’s printed in a book, that anybody can buy. Also I built the flowbench from page 74. Because we have a build where we have to make the best of what we have. Time to see what I have really learned over the last 25 years of reading your stuff. I am just such a huge fan of yours. I didn’t even know you had this channel.
its why lunati created the voodoo cams, to mix with science lol
Would really like to buy your CD for choosing cams, looking for a leg up on building the LS platforms & even Big block Chevy. You have helped me a ton on our sbc builds. Will your CD help our LS & BBC builds? Looking for maximum TQ in the midrange for heavy 4wd rigs. Thanks
Good day David, what equation/formula would you use to picking a Camshaft on a efficient Hemi Headed motor?
Mr. Vizard, great stuff buddy. Thank you for all the free info and experience. I started reading a bunch of your stuff as soon as I saw the Budget Sledgehammer build (which I'm going to build real soon).
I have one question for you though; is your 128 formula applicable to fuel injected engines? Most of the stuff online agrees that to run any fuel injection (aftermarket or stock) efficiently you need a wider LSA.
Thank you for the reply if you have the time.
It's not just interet lore; check out the LSA on factory cams used on the same engines that were carb'd and later EFI. The EFI cams all went to a wider LSA than their Carb'd predecessors. "Chuck Lawrence (John Kasse Racing Engines) received the order to bestow a 520cu in big-block Ford with the sound of a Pro Stock engine, he replaced the normal 112LSA hydraulic roller cam with one of 108LSA. “The result sounded wonderful,” said Lawrence, “but it didn’t rev as enthusiastically and it made 30hp less than normal!”
you can tighten the lsa up a lot compared to factory efi cams. factory cam are very wide. It comes down to how much valve overlap you have and you may have to bump up your idle speed. But vizard talks a lot about making big power with very conservative cams for street engines
Look at the stock cam for the TBI 305/350. That cam specs out at 179/194 @.050 on 109 LSA. These same engines can run an Iskendarian mile-a-mor cam spec'd at 194/194 with 108 LSA or a Melling 184/194 with 104 LSA and the TBI 350 is a speed-density system. Granted, modifying the TBI to have 2-inch bores, better FPR internal spring(18 psi) and installing a fuel pressure gauge will help the TBI setup run better
I would like to implement this formula on a Buick 455, but I always run into a couple issues. First, for a street engine, the overlap quickly gets out of hand for running power brakes with the required 103 centerline. The other issue is that the dynamic compression with iron heads that is safe for pump gas is a problem with the narrow lsa. It requires 9.5:1 or less static compression, and the average build using the available dished pistons comes in at 10.25:1 at zero deck with good sqish. I believe that is one of the reasons many use a 112 LSA. The only solution for both problems is to increase the LSA, but this is not good by Mr. Vizard. What is the solution, or is it just a compromise?
Same formula for BB Mopar with Trickflow 240 heads?
Love to know how to figure right cam for 300 ford daily driver
Hi David where can we buy this book please
How would I determine the right cam for a ford 2300 4cyl overhead cam
Do these apply to LSA or just LCA? whats the difference?
Thank you for your insitghts and video 🙂❤👍
Hi. I have a 1970 Ford 351 Cleveland 4V head engine with the canted valve heads. Would I use the 128 formula for it ? Also my engine has 10.25:1 compression. The side cant on the exhaust valve is 3 degrees. The intake valve side cant is 4 degree 15 minutes. The valve angle for both valves is 9 degree 30 minutes. Thank you for your info.
This channel is dead for now, find his other channel here: www.youtube.com/@DavidVizard
David, Got a question, should I loosen the LSA on 4x4 vehicle, like one or two degrees, for just a bit more low end, or just shorten the duration?
Shorten the duration
David: I wish you had a engine building and dynamometer shop in my area you would be busy all the time with a 6 month waiting list
My 2nd to last 4WD was an Australian release TRD Hilux 4000SL. I knew that engine/blower combination was special from when I drove it out of the showroom. Just did the math and worked out to 1.384 ft/lb per cu/in for a “stock” engine. I understand this has the blower on top too which obviously bloats the numbers but a really under appreciated engine as it was released right at the time of the GFC. Nobody wanted to spend the $$ for one
Now imagine getting that much torque on that engine WITHOUT the blower - - just on the build !!
@@peterdarr383 nah, rather not imagine or waste time on non boosted applications nowadays. Cheers 🥂
So I need a 102 lsa to maximize my performance
I got your book and ive tried a few things and it works great! I want to have a cam made but when i use your duration calculation i get 276 . Does that 276 mean advertised duration or at a certain check height? The book never tells you
This channel is dead for now, find his other channel here: www.youtube.com/@DavidVizard
OK, I'm new at this & have no idea how to do the calculation, I need the formula written differently, what do the / mean in the calculation
That's division. 10.5 to 1 is compression ratio. Divide CID by 8 then divide what you get by valve diameter, then multiply what you get by 0.91 then calculate 128 - ANSWER. This channel is dead for now, find his other channel called David Vizard.
@@SinsBird thanks a bunch sir
I must be doing something wrong. I'm getting 104 for a 350 with 2.02 valves
Could you do a video on how to calculate what camshaft to use for the rpm chosen. Im still confused on your methods. Thank you for your immense knowledge you share with us.
Read his 2oo6 Hot Rod mag article " Compression comprehension"
Go to Controlledinduction.com
@@jrjohn1335 but that doesn't answer the question. That just tells them to spend a bunch of money and plug in numbers into the software. You're not going to learn how to spec a cam for a specific engine like that. Then again, this is one of the main issues at ST. Everyone will tell you what to use and how to spend thousands upon thousands of dollars but not how THEY spec cams. Instead, they'll tell you that you need to redo your entire powerplant and then question everything you tell them about it as if you're lying about it all.
are there any companies you trust to spec and build a cam for you?
@@1flynlow David still does it. type in COS cam walters on google terry walters shop will do it for you using davids program
Is this formula good for 9 to 1 or 9.5 to 1? Is that valve diameter that of a intake? Like 2.02?
10.5 This channel is dead for now, find his other channel called David Vizard, he's made another video about this.
I wish i could dyno my 5.3. The #s indicate im in the 1.3 territory n/a with stock everything except the cam, pushrods and valve springs.
Put your car on a truck scale then run a quarter mile time, that will give you a good measurement of hp
Hi david, i have a engine motorcycle 250cc with a rod length of 103,5mm and 65mm stroke, piston 70mm , valve diameter 33 in intake, how i use that formula to calculate the LCA for making me camshaft, its engine for dragracing 250meters! Thank you
That formula won't work for what you're wanting. Your engine has about 1/3 the cylinder volume of the engine style that equation is made for. A smallblock Chevy has a cylinder volume of about 43.75 cubic inches or almost 750cc. Your 250cc bike's cylinder volume is closer to 15 cubic inches. Around 1/3 the size.
There's no way that equation could possibly be used to spec even a somewhat usable camshaft for your bike.
Understand that David derived this equation from thousands upon thousands of dyno tests and the info he collected from those smallblock Chevy V8's.
To formulate something like that for a 250cc bike engine, he'd likely need the same sort of info. Thousands upon thousands of results to sort through to look for patterns, etc... The only thing that may be somewhat comparable would be if he had something like this for 'Mini' engines aka Mini Coopers, etc...because I would expect them to have small enough engines that it could possibly be comparable.
He ain't answering _nuthin!_
@@20alphabet lol
Do you have a formula to pick a cam for LS gen 111 engines?
This channel is dead for now, find his other channel here: www.youtube.com/@DavidVizard
Mr. Vizard, You wrote a book back in the day on tuning Triumph engines. In regards to the 2L inline six (GT6) would the 128 cam formula apply to this particular engines. My calculations indicate that a LCA of 114 + would be the angle on this motor, however in the Triumph cams the LCA of 110 is what is available. please let me know what you think
I've always been under the impression that It applies only to Small Block Chevrolet V8 engines. Ford smallblock use a different number, 127, and Big Block Chevrolet engines use a 3rd number, 133.5, that's different from each of the previous numbers. Fairly certain those are all correct.
I also seem to remember there being a number, 132, used also. That likely could have been for the BBC, then David modified the equation for better accuracy by using 133.5
He did say somewhere that if in doubt, an earlier intake opening will get you a lot better results than a later one.
He ain't answering _nuthin!_
Mr David can a 5.7 hemi run good on a 108 LSA thanks love ur channel
This channel is dead for now, find his other channel here: www.youtube.com/@DavidVizard
Do you have a formula for the Harley M8 ?
Can we talk gas mileage ?? I already had a 7 MPG Camaro. I'm building a "83 Firebird lightened to 3,100 pounds with a 350, 700R4, 3.23 gears.
I have single and dual-plane Edelbrocks, several Holley, Rochester and Edelbrock carbs, a "Fluidampr" and flat-tops.
I need cam specs and head choice. Compression should be under 10.5 - going for a fun street sleeper as the car isn't in good paint.
Was thinking shorty headers, but unfortunately dual exhaust doesn't fit well under these cars. Currently log exhaust to stock muffler.
I believe gas will go back up to $5.00/gal so crazy, lumpy cams are out of the question.
- - Previously - - I built a roller 305 Firebird that got 28 MPG highway with a leaned-out Rochester and mostly "stock" set-up. Suggestions ??
This channel is dead for now, find his other channel here: www.youtube.com/@DavidVizard
Funny, the custom cam I bought matches up perfect to your 128 formula
Yep, his book has been out for years and cam customers like me always ask for the specs that he promotes (and has the HP figures to back them up) and they have come around to his way of thinking. Even GM uses him.
@@PerformanceEngines I used Jones Cam Designs. I have never seen anyone have a single bad thing to say about his cams, especially for the typical sbc. I don't even pretend to know what the basics of cam design are, but I do have enough sense to contact an expert to get me the result I'm looking for.
Hey David. Quick question. Say you needed to increase chamber volume by 3cc. What would be the best way to gain those 3 cc's in a Vortec chamber?
I'm sure he would say by unshrouding the valves properly.
He ain't answering _nuthin!_
Check out my Vortec porting series.
Slight dish on piston under chamber. Easy peasy.
if the heads are untouched definitely unshrouding valves and the exhaust plateau and rounding any sharp edges.to reduce heat risers
So do you change the 8 with a 6 or 4 for when your speccing out a 6 or 4 cylinder?
This is a very narrow window formula for specific apps. It DOES NOT apply across all 4stroke engines. Not even all small block chevrolets.
Edit:for what it is designed for, it is nearly spot on, but even David will tell you this is for a specific application.
Yes. The first part of that formula is ''cubes per hole''.
and if you have canted valves change the 128 to 131.
OK, I'm a noob, so be kind: I know what LSA is [Lobe Separation Angle], but what's LCA? Same thing by another name, or some other critter entirely? I'll keep watching to see if the explanation is forthcoming, but I just had to pause & ask when I read the formula... OK, it was: "Lobe Centerline Angle." Still don't know how that relates to LSA, but will continue watching & learning & who knows, it may yet be revealed! Thank you Mr. Vizard!
Lobe Separation Angle is the number of cam degrees between the intake and exhaust lobes.
Lobe Center Angle is the angle in crankshaft degrees of THAT particular lobe in relation to top dead center of the engine for that cylinder being measured.
LCA is LOBE CENTERLINE ANGLE . LSA is the distance between lobe centerlines at centerline of the top of the lobes not necessarily exacting peak. So the more lift for a cam with the same centerline angle, the cam can grow in lsa without anything else being changed in design but lift.. But this does not happen because of the lift to duration ratios are always close enough to hardly change by merely changing lift to duration, although can be adjusted any way by different lift and duration ranges.
LSA, lobe separation angle, is ground into the cam. It's Permanent. LCA, lobe centerline angle, can be changed through indexing the cam when degreeing it in. They're not the same thing.
I dont know how to work out that equation to get the right answer ! Im not good at math !?
How does the formula change for 9.5-1 ?
well the number at the end the 0.91 probably change between .90, .89, . .88 or lower. Only guessing here.
Does anybody know if this works on VW air cooled engines?
This is specific to the small block
I got 105 for my 419c bb mopari engine hmm
107 ?
Do you do much LS engines?
If only this applied to LS engines with higher flowing heads.
David this is alil over my head. I watched twice & tried to keep up but I have to many questions in the beginning that you leave me behind. Although this is exactly what im interested in! I love the math & the science involved in engines! I've self tought over the yrs kinda, dont want to not give credit to those that have takin me in & helped me but what I mean i dont have a single person that has always been involved in engines that was close to me therfore I was always around engines. No, I just simply had a overwhelming interest so I would seek out information. I would get two respectable mechanics & one would tell me how chevy is clearly the best & well, fords are junk. But another, equally respectable, would tell me he likes fords & dont listen to that crap. Witch drove my curiosity even more! I wanted to know if one was better & why it was better & why people that literly work inside these engines could give such different answeres. Anyway sorry about the long speech. I know more than alot of people that work with cars & least around here, but im not up to this speed yet. Can you help me learn this or point me in the direction that can help me understand more. This is not how I make my living, this is just my hobby. But I make my living to support my hobby, its my passion!
Hey Jesse, I read your comments and it’s struck a chord with me in a similar way about the fascination of engines and all that makes them tick. I guess a was lucky to have my late father help me when I got my first dirt bike at 5yrs old and pretty much said “I’ll show you the first time, then next you’ll fix it”. That’s how I got started which I’m very grateful, and then onto diesel mechanic, but I’ve found from a lot of great channels like David’s but in more layman terms to help build the foundation which I’ll admit, I’ve learned bloody heaps haha. Do you follow many other car people or engine building channels on TH-cam? Let me know mate and I might be able suggest a few you may like that could help. Cheers mate. Jim😄✌️
@@FizzaMC Buy his book "how to make Horse Power with any engine" Bible and you won't need a interpreter
@@PerformanceEngines hey, I think you may have tagged me instead of Jesse in your comment. All good and great advice for Jesse. Cheers ✌️😄
Jesse, For a starters buy my book 'How to build HP" from Amazon.com
Mr. Vizard would you care to give me 5 minutes or less of your time, and direct me to getting the right camshaft?
Ye ye ye
This formula does not make mathematical sense! A valve is a circle, and the area of a circle is achieved using the formula π*r², this formula uses the diameter of the circle, but increasing the diameter of a circle by 5% increases it's area by ~10%! This formula may work for a specific valve diameter, but it cannot possibly work for all valve diameters!
I'm sorry I'm very sure patients when it comes to watching videos if you have information to put out just put out all this other needless to know information just makes me want to pull my hair out. And like I said Dyno results speak just place them up and the results speak for themselves
Dave Lang said you're good at one thing... selling your stuff. By the lack of response in this comment section I take it your information is indeed _not free._
AND WHO EXACTLY IS DAVE LANG?
THE FACT YOU ARE WATCHING THIS INFO FOR FREE WHICH COST ME A SMALL FORTUNE TO GET SORT OF CONTRADICTS DAVE LANG DOES IT NOT?
BUT THAT ASIDE I HAVE SPENT OVER A MILLION BUCKS ON RESEARCH IN THE LAST 50 YEARS. COULD YOU EXPLAIN TO ME IN VERY SIMPLE TERMS WHY I SHOULD JUST UP AND GIVE IT AWAY????
WITH MAYBE A QUARTER OF A MILL INVESTED IN GETTING THE KNOWLEDGE REQUIRED DO YOU THINK YOUR DOCTOR SHOULD TREAT OR GIVE YOU THAT KNOWLEDGE FOR NOTHING?
@@marvingvx1 thank you sir , I my self have learned a lot from your books and articles over the years and I would have paid much much more than what you charged. Thank you again for your hard work and dedication and I look forward to learning more from you.
I have been reading his articles and books for many years. For a price not too far north of 'free' I have been rewarded with a treasure trove of useful information. Every time I have put that information to the test, I have found that the result spoke for itself.
@@marvingvx1 there will always be those that want something for nothing. Pay them no mind. I have a few of your books, and have found them invaluable in my quest for more sbc horsepower. Thank you sir for posting these videos and little tidbits of tech info for free. I think I speak for the masses when I say. Thank you!
@@marvingvx1
All caps? Sorry to upset you old chap. And you know very well who Dave Lang of Fuel Curve West in Upland, Ca. is.
Are you still blowing your trumpet. Is this about engine's or you. Get to the point.
When I read a book you had, I understood and agreed with everything you said, I understood. Now I have a stack of your work, I have used it without fail for years. I had retired. Now I am going to help my son with a turbo ls engine. I am anxious because I will make the ls engine fly. They are remarkable. I would like to hear what you have to say about them