Anyone have proof that a long stroke makes torque?
01-19-2014, 04:12 PM
#41
Sorry OP for the off track.....
01-19-2014, 04:54 PM
#42
All that nonsense about the GM & Ford engineers... These are the same guys that gave us the Cadillac 4100, the Northstar (a money pit), Ford Interceptors that are slower than the civilian equivalent, the 4.3L odd fire v6, the 305, the Fiesta, DoD, the Cobalt, etc. BTW, I met one of the engineers who designed the 4100. Nice guy, but not a rocket scientist.
I've been working on small blocks since the late 70s. I've built 4 engines, all small block chevy 350s. One of them has never been started so I don't consider it a complete build. I've helped roughly a dozen people with their engine builds. Yeah... I'm one of those dumb engineers who can't deal with reality.
Displacement has a direct impact on fuel economy. Air/fuel ratio must be at or near 14:1 for all engines. The more air required to fill the cylinders, the more fuel is required to make it operate correctly.
My truck has 3.73 gears and I'm not changing them to get better economy out of a 6+ liter engine. It gets roughly 17mpg on the highway with the stock 5.3L. The 4bbl carbed 350 I built for my father got 19mpg with 4.10 gears and no overdrive. Why am I limiting the displacement? Because I got pretty close to what I am looking for using an old gen 1 350! With all the high tech advances in induction, ECMs, etc. since then, I SHOULDN'T NEED MORE THAN 350 CUBIC INCHES!
Lastly, I've read the comments in the forums talking about how you need to stay under 10:1 compression on these LS engines to run on 87 octane gas... Seriously? None of my old Gen 1 350s ran less than 10:1. My LT engines' stock compression starts at 10:1. What is wrong with the LS engines that they can't do better on pump gas? Maybe it's those expertly engineered small bore blocks that are the problem. Then again, maybe it's because they can't use reverse cooling on the LS engines because the idiots at GM tried to steal the design from the original inventor when they made the LT engines and they got their butts sued.
I've been working on small blocks since the late 70s. I've built 4 engines, all small block chevy 350s. One of them has never been started so I don't consider it a complete build. I've helped roughly a dozen people with their engine builds. Yeah... I'm one of those dumb engineers who can't deal with reality.
Displacement has a direct impact on fuel economy. Air/fuel ratio must be at or near 14:1 for all engines. The more air required to fill the cylinders, the more fuel is required to make it operate correctly.
My truck has 3.73 gears and I'm not changing them to get better economy out of a 6+ liter engine. It gets roughly 17mpg on the highway with the stock 5.3L. The 4bbl carbed 350 I built for my father got 19mpg with 4.10 gears and no overdrive. Why am I limiting the displacement? Because I got pretty close to what I am looking for using an old gen 1 350! With all the high tech advances in induction, ECMs, etc. since then, I SHOULDN'T NEED MORE THAN 350 CUBIC INCHES!
Lastly, I've read the comments in the forums talking about how you need to stay under 10:1 compression on these LS engines to run on 87 octane gas... Seriously? None of my old Gen 1 350s ran less than 10:1. My LT engines' stock compression starts at 10:1. What is wrong with the LS engines that they can't do better on pump gas? Maybe it's those expertly engineered small bore blocks that are the problem. Then again, maybe it's because they can't use reverse cooling on the LS engines because the idiots at GM tried to steal the design from the original inventor when they made the LT engines and they got their butts sued.
Injected engine are kept near 14.7:1 AFR at cruise because emissions PPM are lowest, engines will run well leaner and get better MPG but the PPM of unwanted emissions gases like NOx goes up. Carbed engines not relying on O2 feedback are often tuned leaner than 14.7 at cruise.
Far as displacement=air volume you are completely ignoring the fact we operate gas engines under manifold vacuum. If a larger engine can do the job with less manifold pressure/more vacuum it isn't moving more air mass.
Far as OEM engineers, sure they have gotten things wrong, but if they get a lot more right.
OEMs also chase miniscule mileage gains, if they can get .01mpg better under the flawed EPA tests they will do that vs. giving something that actually works better in real driving. The rest of us will never notice .1mpg in our gas budget much less the OEMs chasing .01
01-19-2014, 05:05 PM
#43
On The Tree
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01-19-2014, 05:33 PM
#44
On The Tree
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01-19-2014, 06:19 PM
#45
Well, I think that if you have set a goal, the best thing to do is the cheapest, yet reliable way of getting to that goal. From your requirements in other posts, I would agree with the others here who suggest getting an off the shelf stroker from a sponsor.
Why all the mental exercise, if you can meet a goal that is possible with proven combinations? No reason to reinvent the wheel.
Why all the mental exercise, if you can meet a goal that is possible with proven combinations? No reason to reinvent the wheel.
01-19-2014, 06:32 PM
#46
Nothing about the EMC seems relevant to the topic to you?
Back in 2012 I think, BES dominated the competition with a 417ci Hemi. It had a 3.950" bore and 4.250" stroke. This was the reason there are now two classes within the EMC. With an 83 cubic inch deficit, this 417ci Hemi make more peak torque than another competitor's 500ci Olds engine.
Back in 2012 I think, BES dominated the competition with a 417ci Hemi. It had a 3.950" bore and 4.250" stroke. This was the reason there are now two classes within the EMC. With an 83 cubic inch deficit, this 417ci Hemi make more peak torque than another competitor's 500ci Olds engine.
01-19-2014, 06:55 PM
#47
On The Tree
Thread Starter
Well, this was interesting, but the bore is too small for my tastes 
http://www.youtube.com/watch?v=52pNn...ature=youtu.be
http://www.youtube.com/watch?v=52pNn...ature=youtu.be
01-19-2014, 10:57 PM
#48
You're mixing things here. Yes, other variables such as valve events, timing, compression, etc. have a direct effect on piston speed as they can increase or decrease the effective rate at which the engine is able to accelerate through a given RPM range but they in and of themselves can't change piston speed. Piston speed is a direct calculation of RPM & Stroke...the piston will have to travel at (x) speed to cover (y) distance for any given RPM and stroke, the only thing changing is piston speed. As I said, it makes no difference with the other variables as they don't change the speed needed to cover said distance, they just affect the engine's ability to move from say, 3500 rpm to 3501 and so on. Two completely different setups with the same stroke/deck height will have the same average piston speed at any given RPM, the one optimized the best WILL however have better acceleration and thereby create more power by use of rotational mass.
In other words, the stroke WILL determine the piston speed.
In other words, the stroke WILL determine the piston speed.
01-20-2014, 12:44 PM
#50
On The Tree
Thread Starter
Nothing about the EMC seems relevant to the topic to you?
Back in 2012 I think, BES dominated the competition with a 417ci Hemi. It had a 3.950" bore and 4.250" stroke. This was the reason there are now two classes within the EMC. With an 83 cubic inch deficit, this 417ci Hemi make more peak torque than another competitor's 500ci Olds engine.
Back in 2012 I think, BES dominated the competition with a 417ci Hemi. It had a 3.950" bore and 4.250" stroke. This was the reason there are now two classes within the EMC. With an 83 cubic inch deficit, this 417ci Hemi make more peak torque than another competitor's 500ci Olds engine.
01-20-2014, 12:50 PM
#51
On The Tree
Thread Starter
They are $2500 to $2800. I am willing to spend that much for what I want. If you find the LSX 454 block for $2000, let me know. Due to growing mechanical issues on the existing engine, I need to replace the long block now. The other cool stuff can wait.
01-20-2014, 12:53 PM
#52
On The Tree
Thread Starter
Those builds are so neat AND goofy all the same. I remember one of the first ones where they were 365 inch, 91 octane, and 2500-6500 rpm range. IIRC Beck racing built a .060" over 307 block (3.94") and stuffed a 3.75 crank in it with some AFR heads and finished 2nd or 3rd. Other freaks showed up with 13-16:1 compression and admitted they were dyno queens and were freshened just before the test to minimize oil contamination which would cause major detonation. I wish they would do one with shelf parts only that anyone could order from Summit/Jegs and duplicate instead of all the trickery and coatings that make some of those builds major expensive.
Sorry OP for the off track.....
Sorry OP for the off track.....
01-20-2014, 08:30 PM
#54
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01-20-2014, 08:54 PM
#55
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I remember an article a long time ago on a sbc build, stroked 383 vs destroked 377. There was little difference in hp/torque curves. I think Tony Mamo did the builds.
01-20-2014, 09:03 PM
#56
On The Tree
Thread Starter
Maybe, but you compared an Olds to a Dodge Hemi... Might as well compared a Yugo to a Porsche. I've owned an Olds engine, had to work on an Olds 455 "Rocket." I'm not a fan.
01-20-2014, 09:09 PM
#57
On The Tree
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If I had to pick the number one reason I am considering the 3.26 stroke with 6.275 rod combination, it's the promise of being able to run higher compression on cheap gas. I think we can all agree that compression creates power.
01-20-2014, 09:12 PM
#58
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01-20-2014, 09:32 PM
#59
01-20-2014, 09:47 PM
#60
A short stroke with a long rod tends to dwell the piston at TDC longer which helps compression limited circle track engines. A long stroke or over square engine tends to accelerate the piston at and near TDC which helps reduce detonation and usually requires less total timing to make peak power !!!!