Rod Ratio - Dyno tested
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- เผยแพร่เมื่อ 26 ก.ย. 2021
- Dyno testing connecting rod ratio
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Test engine:
Modified early bigport head
Kelford 193b 9.2/8.5mm 284/278 @ .3mm
Toda valve springs
Toda inlet cam gear
Redtop bigport block with 10.3:1 smallport pistons
Toda 3.7kg flywheel
Maxpeedingrods connecting rods
Link G4 ecu
47mm itb long runner
Garage 4age Header and 3" exhaust - ยานยนต์และพาหนะ
This would have to be one of the most labour intensive 6 minutes total of filming ever. Many thanks. Well done
Well done for going to the trouble of doing something that took a lot of effort and having hard numbers instead of speculating like everyone else. What I am curious about is how much less internal stresses are on the engine with the long rod to stroke ratio.
Its higher stress for conrod due to higher slenderness. Forces for bending are higher, so for boost conrod needs to be even thicker/stronger
@@starydwumas7481 The stress on rods comes from low end torque and or piston weight. The stress on piston side walls are less on a longer rod.
@@rickyr7790 you write that because someone on yt told you that or you actually had lectures about materials durability? More slender shapes are more prone to bending during squeeizing. It's a fact. I didn't invent that. It's like you would argue about Newton second law.
In fact low end torque put stress for Conrod but from different reason and it's not related to it length.
@@starydwumas7481 ok. And the differences between these connecting rods and most connecting rods, when changing rod ratios in consumer applications, will be marginal. In the real world, people often see rod failure (from stress) due to high low end torque.
@@starydwumas7481 I thought that was too obvious? Just use a thicker, longer rod so you have all bases covered ;)
Why this channel still underrated ?!? I love the content, Everytime simple and very intuitive on numbers, no stupid loud music.
Not enough stuff blowing up i guess🤷♂️
This channel doesn't get paid to push products like the stupid loud music channel.
@@Garage4age No real gearhead wants to see that. Your channel is just great.
The internet loves to argue about this one. What kinda sorcery is going on here? Few notes; I had already tested and come up with the cam timing numbers, which I think is the best compromise and best compares to the stock rod engine. hence why some of the changes may seem aggressive.
Obviously I couldn't back to back run this one. The run from the stock rod engine and the runs for long rod engine, were both done one very similar days according to the dyno weather station. correction turned on. uncorrected numbers compared the same, just show a couple kw more due to weather. If anything was in favor of the stock rod engine, as was run up 5 deg hotter oil temp, and was the highest power it had made corrected.
Edit: Just to clear things up. The only things changed between the 1.58rr engine and 1.78rr, was the block itself and the rods. I literally took every part out of the 1.58rr engine, put it in a taller block, with custom rods to keep the deck height the same. That means pistons, pins, rings, crank, bearings, oil pump, even the same oil filter! compression ratio and capacity is the same
Would you put the power gain down to less wall force & hence friction experienced by the pistons or something else geometry related?
Where did you find pistons for the different rod ? Different pistons could produce different results as well. E.x. fresh rings compression combustion design clearances e.t.c
@@nick_parker A friend done some math and come up with 15% less peak side loading. could be something to do with the piston speed and combustion event also. I just build it and see if it works..
@@ngt84 Same pistons. same everything, same rings, same bearings, same crank. I even used the same oil filter! only change is the rods and taller block. I had the rods custom made to use same pistons and to keep deck height same
@@Garage4age so compression ratio is the same regardless of the block height difference?
this is the most informative youtube channel in terms of n/a engine, gains and demystify a lot of especulations about engine mods, thank you a lot. You do a lot of work and we learn a lot.
There's a 2.625% difference in piston inertia at the same rpm between the two rods which is pretty spot on with the percentage increase in power at the top end. Cool!
The piston's longer dwell time at TDC may also have made a small difference too (after tuning).
Secondary engine balance is also 10.94% lower (The engine will rev/run smoother).
Both Engines Share
=============================
Piston Weight: 420g (updated thanks to @Garage 4age's comment)
Stroke: 77mm
1.58 Rod Ratio (122mm rod) @ 8500 rpm
=============================
Max con rod angle: 18.395 degrees
Max piston inertia force: 1707.7 kg
Mean piston speed: 21.82 m/s
Max piston speed (corrected for con rod length): 35.95 m/s
TDC - BDC piston inertia force difference: 819.3 kg
1.78 Rod Ratio (137mm rod) @ 9000 rpm
=============================
Max con rod angle: 16.321 degrees
Max piston inertia force: 1864.3 kg
Mean piston speed: 23.10 m/s
Max piston speed (corrected for con rod length): 37.70 m/s
TDC - BDC piston inertia force difference: 817.9 kg
1.58 vs 1.78 @ 8000 rpm
=============================
Piston inertia force: 1512.7 vs 1473.0 kg (-2.625%)
Max piston speed (corrected for con rod length): 33.84 vs 33.51 m/s (-0.98%)
TDC - BDC piston inertia force difference: 725.7 vs 646.3 kg (-10.94%)
Do you think the weight of the taller engine block is worth the extra power?
Thanks for the maths! In this case not really worth the effort. considering what can do with a stock or near stock 4age bottom end. But have other things planned for it. add another 100g or so for the piston and pin weight btw, i forget the actual numbers
@@Garage4age Thanks for the testing. I added another 100g to the 320g piston weight and updated my original comment
Sticky please, it would really cut on all the non useful comments.
@@Garage4agedo you forsee extracting more power by increasing the RPMs?
Mate, you're an absolute legend for sharing this info. I've only ever read about the benefits of a long rod vs short rod, but nobody has ever shown back to back findings like you have. I'm sure this was all very labour intensive, thanks for making this video and sharing what you've learnt
I admire and salute your efforts mate.
998cc A series has a 1.91 rod ratio. you may not like it, but this is what peak performance looks like
yeah thats some godlike stuff right there. Maybe i need a 2a crank in this block..
My first car had a Nissan version of the 998cc A series in it, and that was certainly the peak of performance!
Interesting that the SR16VE has an even high ratio, over 2:1 I think.
Very cool to see this , engine masters did one and I’ve always wanted to see one on something more relevant than a 350 chev … awesome test
Nothing could be more relevant than a 350 chevy to many many people...especially in the US
@@mitchellsteindler I second that opinion
@@mitchellsteindler I suppose it’s the U.S vs the rest of the world argument. The better part of Asia (including where I come from) don’t even bother with engines greater than 3.0L, let alone a 350 CI V8.
Lol v8 not relevant
The testing you do is amazing. Great work!
Very cool test! I've always wanted to see that done. Thanks alot.
Thank you for working your ass off to make this video. I always try and run the longest rod I can, for less side loading on piston skirts, lighter piston, etc. this is very interesting, as I haven't found any extra power either.
I love your videos! it's a huge effort that you take, hours, days remake inlets, exhausts, engines.... put some time lapse of that at begging to make 10 minutes video at least! cheers bro!
That's really cool. I've always wondered how this exact test would come out on a different engine, the 2azfe, which has a little brother with destroked crank and could be built long rod short stroke and 88.5 bore to be about 2.1 litres. What I find awesome is how little it lost down low and at midrange rpm before showing a stronger top end over rev. Very cool.
Loving the longrod. (7a block) combo.
I was thinking about doing this myself.
My God is that the thing I was dreaming to see for such a long time! Thank you so much for this! If I could put a million of that thumbs ups I would definitely do.
Really good and interresting stuff!
Keep it going 👌
Wow!!! Big effort here, thanks so much!!
now you really became my fave channel as i been telling about this to most people and always falls in def ears... weldone I better buy some merch now....
Thank you so much for doing and sharing this experiment!
I was always under the impression that a higher rod ratio would allow you to rev the engine higher due to lower piston speeds and less thrust force on the cylinder walls, and that just by itself it made more power. The higher potential rpm is what usually makes the power, not the r/s ratio itself, I think.
There is many small effects that happen when you increase rod ratio. The main too are lower piston speed and reduced piston side loading and less fiction as a result.
Power can be mainly made both from torque (diesels, turbo) and rpm (NA), but you should always aim for best volumetric efficiency across whole RPM range - thats what makes the car fast. You can increase rod ratio by putting longer rod into it and still you can't rev it higher. Am I missing something?
@@wackydriver yep longer can hold the cylinder fill, which is basically torque, more power its going to make with rpm. frictional loss are higher as rpm goes up, which is likely the main reason for the power gain here. same thing can be seen with oil temps, engine will gain power in similar rpm range. Didn't do much if anything in for the engine VE wise, as required the same or very close to the same fuel. If the power rolled over at 6000rpm rod ratio would have done nothing for the engine
longer rod will not change piston speed, just side loads.
@@gigigalli6578 Actually it will. Piston speeds are directly influenced by stroke length and connecting rod length, ie a short stroke and long rod will have lower piston speeds than a short stroke short rod. It's one of the reasons F1 engines can spin well above 15k rpm
Amazing. Thanks for sharing your findings.
Great job you're doing. Congratulations
Awesome little test mate!
Thank you, that was a lot of work for you!
Man, the most important video of my life! I want built my engine with rods 6mm bigger than OEM, let's watch the video and learn something.
Back about 96 we did SBC rod tests and determined that the power difference was not enough to make a real world difference... considering time and $$.
Great information and fantastic work 👍
That was a lot of effort. Cheers for that.
You really REALLY make this look easy
Love the vids man!
This is pure gold!
Sorry to be so late to the comments on this. Thank you for all the work you do to give real world tests, real world people appreciate it. Coincidentally have been developing a modernized Ti long rod 18rg. Here is how that came about....
#abetterdragonengine
Its whats inside that counts. Titanium long rod 18rg coming soon. Was shopping the clearance page over at Pauter Machine. Found a set of titanium 3RZ rods on sale 60% off, less than half price. Scratched my head and hours of math and spoke to Ross Racing Pistons. They are just shy of 9mm longer than a stock 18rg rod, so we will need to build special pistons. Why? Rotating mass and rod ratio, 1.8375. These weigh a little over half the weight of the stock rod , whole rod is less than the big end of the stocker.
Sometimes you get lucky, I sure did. Thank you Pauter.
Definitely gonna get a rev limiter.
Thank you Don and Mario.
Thank you Cary for always answering my 18rg questions.
Mario asked me the other day, why do we do this?
Cause we love figuring this stuff out.
....just changed car platform to a TE31COROLLA. One day I will be able to fire engine up and see what it will.
Again Thank you for the preview. Not everything is about the HP number, sometimes it is about how you get to the HP. Like saving almost 1lb. Per cylinder.
A really good video, thanks blokes!
Billzilla.
Longevity improved and more hp the improvements are more than what it seems
Good stuff! Lots of work, thank you! I would have figured longer rod more torque, but not more horsepower. Guess that's why you do these videos to find out!
For the sound alone this Cideo3is worth watching!
Highly interesting!
I long rodded my 302w and it was worth every HP the way the engine picks up revs and responded when your driving is where your truly experience the difference. A Dyno won't show how much better it feels just the marginal HP gains.
I did the same to a 302 clevor. Seats of the pants feel.
Great test.
That R/S concept goes from the older OHV V8 stuff. You can see the little drop down low, which is not taken in consideration as it is a high rpm engine. With a longer rod the piston spends more time closer to the spark plug making a better combustion at high RPM, but sucking at low RPM is more abrupt. It would be more pronounced if you had to move a lot of volume like in a V8 engine. The engine can’t suck more than the volume port basically, despite having a lot of pressure waves, it can’t suck in more volume than the dynamic relation of cylinder/cam size.
So a very wise tuner/engine builder here in US explained it to me very well.
In Smokey's and The likes day,
They did not have aftermarket heads that flowed. They used to have to message the stock stuff, and being all iron, it took TIME. One of the things they found was, adding rod ratio to get a better intake signal therefore a better intake charge. Today, in some setups it will gain 5ish hp maybe. There was a time and place this was new tech.
The other thing to think ab:
Is it worth the extra beating the crank/ journals/bearings are getting? I know of Nitrous guys that added just a bit and couldn't keep a crank or bearings in it. Infact, a lot of the older style "working every round" Nitrous engines imo were because if the extreme rod rat and how it beat the eng apart
Wow. I’m surprised. I didn’t expect such big gains.
So i guess what comes next is the 7a block and crank with the max' rods that fit for it. I really want to know what kinda gains if any are there for this infamous setup.
Bill Sherwood told me this 10 years ago!
But then.... that madman also reckons the 7AFE head is a goer....
It is actually
Would be interesting to try, lack of aftermarket support with cams and the likes though
@@Garage4age you can ground some stock cams tho, although you need an adjustable cam gear(handmade) and a 1JZ adjustable pulley to adjust cam timing on both cams outside the cylinder head, they used to do this trick on 4EFE engines all the time in the early 2000s
interesting to see how much more sensitive the long rod ratio version was to resonance compared to the short rod version.
I would like to see that also.
Great video!!!! Did you notice any difference with the engine response (rev quicker) between the two rods. Thank you.
Thanks! This Videos are Gold! So much information in such a compact format, like it :) Would you consider testing Water Methanol Injection? Maybe a simple setup with Aliexpress garden water spray nozzles?
awesome video, thank you.
How do you find the time to do so many videos so quickly that all involve a lot more work than my project which hasn't run for 5 years now!
awesome. Thanks for sharing!!!
Very cool info! A mod that may be worth it when extracting every last drop from an NA engine I suppose.
This is awesome this is like a more scientifically consistant Richard Holdner. He does some awesome videos that show the BIG picture but knowing the effects of smaller less considered variables is important.
Good job!
It make more sense to use the radius on the geometric plane when speaking of Rod ratio. "Rapport R/L" in French.
The rod lengh is really crucial in determining the difference of average speed between upper zone of the stroke and down zone of the stroke.
This difference make unbalanced harmonics who "kill" the rpm ability (vibrations therefore... power) and decrease reliability of the internals/engine.
...Material fatigue will never show on the bench.
:-)
It must be because of friction why the power gets better with higher rod ratio? Lower rod ratio is favored with undersquare engines, having higher piston speeds and very well flowing cylinder heads, decent headers and intake (either invidual throttle bodies or well designed plenum with single throttle body).
Another thing is burn speed on combustion chamber, that may have an effect on how changing rod ratio changes the power / torque curves.
I do like to think with higher rod ratio, the piston can be made even shorter because of rod angle.
Maybe helping it survive better at extreme pistons speeds.. ? Maybe some day I will know.
Thanks for the great video - again!
I have one for you to test. Knife edge piston skirts :)
Love your content!
My engines have a rod ratio of 1.87 but when the ecotec v6 came out they dropped the ratio down to 1.58.
never tested myself, but many others have, anyway from all the text I have read over the years, the closer R/R are to 2.0 the better off you are for long term wear on pistons. depending on pin placement, longer rods tend to alleviate piston rock due to the reduced angularity of piston thrust face to rod. You pick up bhp because of reduced friction of piston to cyl wall and probably less gas leakage past rings as they are not forced to deform as badly. Many say it is because the piston hangs at TDC longer ?
the weird dip , is it even there with other runs with diff intakes and exhaust pipes, because I was going to say that the IN and EX pulses are at odds with one another ?
I found this very interesting, mainly because the result was the opposite that I was expecting; I read somewhere that there was a theory that all of the most successful race engines were enlarged versions of previous engines, hence they were stroked and as a consequence they had a long crank throw to rod ratio, an this caused the piston to change direction at the top of the stroke quicker than the bottom which made for a more powerful engine ( I don't know why ) despite the greater friction loss because of the greater con rod angle.
Look at the rod ratios of F1 and MotoGP engines, you'd see that they are pretty high compared to road-going engines.
Increased stroke means the piston has to travel a longer distance per revolution, increasing piston speed per rev. This puts a lot more stress on the piston pin, rod's small end, and the piston. Making these parts stronger usually means adding more material, increasing the reciprocating mass. Increased stroke usually means increased power for road cars that are not designed to rev to 9000+ rpm, but for those that have to rev 9000+ rpm the preferred design is oversquare.
@@sepg5084 I totally agree that friction would be lower with an longer rod, but the theory of a short rod giving more power makes several points, the sharp reversal at TDC is supposed to help scavenging and mean that there's less time for the charge to lose heat after combustion, meaning more heat to expand the gases and push the piston, the longer dwell at BDC after combustion helps the charge to escape before the piston goes up, reducing the effort against the piston, and longer for the charge to enter the cylinder after the intake stroke. It's a bit of a trade off.
Interesting! I think is common knowledge that a shorter rod/stroke ratio gives better cylinder filling at midrange. But is this maybe true only for engines that have extreme valve lift and runs at extreme RPMs even with a long stroke? (I'm taking as an example the 4Pistons Honda K27 engine, capable of 10.000rpm with 106mm stroke and over 17mm of intake valve lift).
Thank you
Power curve is negligible between the two ratios but I wonder if piston speed and sideloading will have an effect on reliability
I do appreciate the effort you went to for this video and I subscribed for that reason as well as I enjoyed it. There isn't a great difference between 1.58 and 1.78 though, but still great effort. Would be nice if you could measure the vibration difference between the ratios. Unlike some of your viewers I am aware of the longer dwell time at TDC and BDC with a longer rod to stroke ratio and the reduced secondary imbalance. What RPM were you running up to? My understanding is a longer rod to stroke ratio is better for high RPM and opposite with short rod to stroke ratio. I am building a DIY helicopter using a Suzuki M13a due to its ideal displacement and also the fact that it has at Rod to stroke ratio of 1.98 making it a very smooth engine for an inline 4 cylinder which is desirable for an aircraft. The M16A engine has a rod to stroke ratio of less that 1.5 and it vibrates quite a lot. How is your experience with maxspeeding rods?
Hey, I did think about measuring the vibration. but the equipment looked to be out of my budget. The plan for this engine, was to try make something bit more reliable at high revs for the reasons you say. rather than make more power. I've been running it up to 9600rpm regularly and a few 10k runs. the maxpeedingrods seem to be holding up fine
@@Garage4age I feel stupid, didn't see the RPM scale at the top.
Awesome as always. What oil did you use? I reckon the difference is down to the side wall loading. Supposedly engine oils with added ZDDP provide better boundary layer performance than conventional oils.
just some penrite 10-40 semi in the junker engines, meant to be "full zinc". maybe some small gains going to a thinner grade.
Almost 500rpm extra is way more than I would have expected even if the power was 2% less instead of more, the extra 500 rpm has much more weight. very impressive
To find which parameter makes more power, short or long rod, you have to tune every single last bit of the engine to take full advantage of the shorter and longer rods, not leave them constant.
As an example, which one can use more static compression?
Which one can use more cam?
Which one can use more spark advance?
Which one is less prone to detonation?
Which one can use more overlap? Which one needs less overlap?
To make a truly accurate experiment, one has to tailor each and every possible parameter to maximize the output of that one thing that is changed.
A shorter rod may be able to use more spark advance, or it may need less.
A longer rod may be able to use more cam duration, and it may need less overlap.
It is not experimentally accurate to use a set of parameters that only suits one rod length to test both rod lengths.
It's like saying, "Is grass a good muscle building food?" and feeding grass to a cow and a lion, and using the cow's results to prove that you don't need animal protein to build muscle.
The ultimate power-producing potential of a rod length ratio can only be found by maximizing all parameters of that engine to take maximum advantage of the behaviors of that engine with that rod length.
It is too cheap and too easy to just freeze all parameters at a state that may completely favor the longer rod or shorter rod, and then announce, "See? That proves that long rods are better!"
It reminds me of saying, "Does 6:1 static compression produce more or less power" then using it on an engine with a 125 percent overdriving roots supercharger, where it is needed to not over-compress the intake charge, and also using it on a naturally-aspirated engine, and concluding that 6:1 sucks because the engine that is naturally aspirated either doesn't make good power with that, or you have to run it at 1000 RPM to utilize it properly.
To TRULY test the rod length issue, you need the entire engine to be built to take maximum advantage of the piston's behavior and dwell time near TDC, speed just before and after TDC, and all the other changed parameters that are piston and rod-related. As with 6:1 compression being useful, you have to build the engine to take maximal advantage OF 6:1 compression, either super-low-RPM, or with very high-pressure-ratio supercharging/turbocharging.
Freezing any set of parameters merely proves that on rod ratio performs better WITH THAT PARTICULAR SET OF OTHER PARAMETERS than does the other, which is meaningless, like declaring red-brown camouflage to be inferior because you tested it in a jungle instead of a red-brown landscape.
To truly ascertain the ultimate power-producing capabilities of something, you need to maximize all parameters surrounding that one thing you changed to suit it, then change them to those which suit the other thing.
A shorter rod spends less time near the top of the cylinder, and MAY be able to use more timing. It MAY profit from less overlap, but may reward more duration. These are things only very thorough actual experimentation will demonstrate, not incomplete tests done with a set of parameters that may be more prejudicial to one of the rod lengths chosen.
15,000 RPM F1 engines, WE ARE TOLD, (but who knows what the truth is, as if the engine builders will EVER tell you their secrets,) have a long rod ratio. Mercedes engineers are more likely to show you their underwear color than reveal a single thing about their motors, I think, and rod ratio is a very big component, not a small one like "we use aluminum blocks."
You'll need to pay that f1 team to give you those answers. not some guy on youtube doing it for free. fyi i didn't build the long rod engine to try make more or less power. more for high rpm reliability
Great video, it's interesting that you've now got another 500rpm of useful power. Probably a better gain then the extra kws.
Interesting where are this 500 RPM came from?
@@turbotyoma from memory a longer rod ratio equals a slower piston speed, also less side load on the piston. This may allow the motor to perform better at high engine revs.
@@andrewgrace1350 yes, but RPM limit is changed also?)
I just changed the limiter as wanted to see what it would do up there. can see the effect of the cam timing better
@@Garage4age thank you! Great videos!
Very interesting video. Thanks a lot! I have long wanted to know how the R/S ratio affects engine performance and seems like it almost nothing - around 3%. So, may be even tolerance of expirement due to the different block.
3% almost nothing!? Diminishing returns. You can’t expect to keep finding bucket of power all the time.
@@TofumanFC3S It matters only with huge amount of power and in the real world typical driver on road may find out difference in power that only exceeds 7%. On some engines only changing spark plugs and their indexing can change power by 2-3%.
О, привет! Про RS и его фактическую бесполезность уже писали на турбобазаре, да и вроде BarikCZ тоже у себя в блоге на драйве.
От RS только вопросы надёжности ШПГ зависят.
А вот BS соотношение куда интереснее.
// А я вот думаю - делать крутильный 1.6 или затолкать 1.8 мотокомплект =\
@@devl547 Привет) Про B/S давно в курсе, но вот на практике погонять два конфига на диностенде и убедится что действительно R/S практически не влияет - это прям мега круто) Если у меня был бы 1.6 16 кл я бы без сомнений на повседнев собирал бы 1.8 все таки объем есть объем. А вот поскольку у меня 8 кл, то все таки остановился на ШПГ от гранты.
@@vGamBIT I doubt this testing and building is done to see who can sit in traffic the fastest. 3% is 3%, and that’s significant regardless of in which class you race
Hey man super interested in the 4age Hilux build looking into doing it myself would be great to know roughly how much it cost. Thanks
Pettys did this in nascar in 426 hemi engines, they claimed they could move peak tq and hp numbers up or down the scale with rod ratio. They said best all around was 1.85
Finally, something that can help me with my (currently unknown future) FZR400 project over here...
Just wondering: are those Ti rods, or steel ones? A longer rod obviously stretches longer than a short one (that also increase compression slightly on high rpm) but Ti rods stretch way less on high revolutions so have to add that hi-speed steel stretch on the equation
pretty sure they are forged steel
Would it be so neglible to speculate that the increased frictional losses associated with a lower rod ratio, can contribute to the torque variation?
Could you test engine with stock compression, and with shaved and ported head with just increase in compression?
What if you use the 7a crank and rods????
from what ive read/seen it doesnt really make a difference unless youre running the engine up to crazy high RPM when youre at the limits of material strength. would love to see someone test the idea with an old 80s CBR250RR engine at 19k rpm.
👍🏻👍🏻👍🏻
I had one of them. Was early 90's cbr250rr. 19k readline. Had it open pipe a couple of times. Sounded like the og F1 cars. Could hear it for miles 🤤
Excellent vid as always, good to actually see the effect rather than just reading about it.
Have you ever tried running the pistons the other way round, there's some power to be had due to the improved rod angle at the expense some of engine noise, not sure if its possible with your stock pistons?
Ohh yeah like rotate the pistons 180 degrees. Due to the offset pin, thats not a bad idea.
Hi just want to find out how many mm rods thous are center to center and which block did you use to get the correct deck height.
You could have read Sir Harry Ricardo's "High Speed Internal Combustion Engines"-1934 Oxford Press revised and saved yourself the trouble of testing the short rods. In about 1915 Sir Harry determined for the Royal Flying Corps that long rod engines ALWAYS are more efficient which is why skinny-block Chebbies can't make the power of a Cleveland or ANY MOPAR including the "Leaning Tower of Power" Slant Six. I have personally seen a dyno run of a Slant-Six topping an LT by 22 HP and 17 lbs-ft of torque for 31 minutes. It had six Mikunis on tuned length intakes in a Formula Six sports car chassis and ate 911T's and 'Vettes up at Hallet Motor Speedway for lunch last year.
Thanks so much boet, this was a really interesting video to watch and learn about the difference in rod ratio
The 4kw difference is okay since the longer stroke ratio will also cause more ware on the block
My understanding is that less wear will occur as piston side loading is lessened by effectively reducing the angle between piston center line and rotational center but idk.
@@ordinarysnuffle8115 thank you
Awesome...
Power gain is a bonus anyway...
The real reason is extended powerband and less piston skirt stress at high rpm especially during extended peak run or racing circuit condition
What's the car drive like on the road with the longer rods?Do you gain top end at the expense of bottom end.Im building up a 7A and thinking of going the long rod option from MRP.I'm
hearing an engine with long rods can be prone to knock. I would like to hear your experiences on the subject. Thank you and keep up the good work..
You wont notice any difference down low. I haven't seen any negative effects on this engine. no issues with knock but is only low compression 10.3:1 . Haven't had an engine with that mrp kit. isn't a big difference in the rod ratio over a stock setup. but if you are going to buy rods and pistons anyway, id go for it.
@@Garage4age Thanks mate.Thank you for getting back to me.All the best.
Conventional(?) wisdom says lower rod ratio equals more torque, yes? However, looking at the bottom end of the curve idle hit to say 2-3k rpm doesn’t show that, the 1.58 shows fall off then build, is that correct?
anyone care to hazard a guess whether the HP and TQ increases were from more power or less friction?
Could trumpet changes complement the wider power band
I wish someone would test similar turbos from each brand, holset, Garrett, precision, and BW then add a few china's to the mix. Love to see the results.
Probably no ones done it, because would need about 2milion views on yt to just cover the cost of the turbos
the real tough question is when to trade rod rato for cubic inches when you run out of deck height in a stroker build.
Would the reduced side load increase cylinder TBO?
I get over 1.8 with a Dodge low deck 400cid block and an RB 440cid crank and the 440 long rod for 452cid 10.5 cr 500 - 800 hp depending on the cam and heads
Again a superb video. Real numbers. Curious how the 1,78RR goes up 500rpm more. A lot of work from you , good job, congrats.
I just raised the rev limiter to see what it would do up there. Plus it shows the cam timing changes better
@@Garage4age OK, thanks by your reply.
Yeah the mother fucking boys. Absolute champions.
love the videos
but when editing can you raise the volume of your voice compared to the engine noises?
yeah i forgot to do it on this one.
Hi. First, congratulations for the videos you are making: they are extremely interesting and useful too. I have a question: what is the timing advance with 1.58 rod ratio? Thanks
Somewhere around 30 at high rpm
@@Garage4age Ok ok, so when you say, for instance, "5 degrees retarded", is it referred to that advance, isn't it?
@Riccardo Lari Yeah. The long rod engine I started with the ignition timing 5 degree retarded (less) across the whole map, compared to what it was running on the normal rod length engine.
I run a Mitsubishi evo 2.0 long rod and it's very good.
Realy interesting back to back test.
The hp different is from the rod/stroke ratio or from the different piston shape(Cr ratio,squiz,metal expansion,flow etc)?
Can you find the same piston shape?
Thank you
The pistons are the same items. I literally took everything from the 1.58 engine and put it in the taller block, to make the 1.78 engine. only the block and rods are different. I had the rods made so the deck height is pretty much bang on the same in both engines
What do you think about the idea of friction related losses being lower, due to lower side force on pistons?
@@Garage4age ok!I thought to had the same block height to need replace the piston height. (same deck height)
@@SRTmotorsport yeah block i used is approx 15mm taller
boss gd non,, whereis more power and more top speed,,, long or short rod?? thanks
Hmmmmmm
How are you liking the Maxpeeding rods? Did you have to do any machining on them prior to install?
They seem all good so far. the little ends need a tiny zing to fit factory piston pins, as they are a bit tight out of the box. but thats not a bad thing. Few little burs that need hand finishing in the big ends as they haven't gone back in to do it, after machining to size. Otherwise drop in and go. they weight match the sets.
Every time I consider do a k24 or 3sge swap I come to your channel and learn something new about the 4age.
Do you have the stock t50 transmission? Could you list the rods. Piston. Cam combo you have? I know you have change them so much I lost track of what works with what
Hey, i put the engine spec's of engine being tested in description. yes t50
What would be the diference if It had a turbo or It changes anything?
What is the compression ratio on the long rod vs short rod?
Are you also swapping out pistons, with a lower wrist pin for the short rod?
see my pinned comment. Its all the same apart from rods and block.
Could the dip at 8200rpm be valve train harmonics? It'd be interesting to shim the springs and see if it changes.
More likely something to do with the intake/exhaust tuning. never had an issues with the springs before. only showed up after cam timing changes. which can like a slightly different runner length