Ls2 408 stroker
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From: Portland, Oregon
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505rwhp for my combo is really good for an automatic and a stall.
If my vehicle was a manual there would probably be another 10-20rwhp there.
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From: Mississippi
Im go estimate at least 645 horse at the crank. Thats 1.55hp per cube. You should get there with the CNC heads and the strong compression ratio you are at. Do you plan on running 2 inch headers ?
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I also have 100 CPSI catalytic converters with 4.5 inch bodies.
I did an experiment 2 years ago actually on my stroker engine.
I had a 1 3/4 size headers on there, and I wanted to upgrade them to a set of 1 7/8 ceramic coated headers (which I still have)
Guess how much power and torque I gained?
1.5rwhp. so basically nothing.
I did notice though that the vehicle felt more responsive down low.
No loss of torque either.
Maybe the smaller size has better scavenging at that power level.
Who knows.
I'm hoping for at least 650hp at the engine.
It's about 630hp at the engine now if you include a 30% drive train loss etc.
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As I stated earlier, I gained no torque but i did gain 1.5rwhp up top.
The bottom end felt more responsive though but not torquier.
From memory the dyno curve looked exactly the same as with the 1 /3/4 size headers.
Maybe now with a more appropriate camshaft with better timing events it will be even better.
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From: Mississippi
Every engine is different.
As I stated earlier, I gained no torque but i did gain 1.5rwhp up top.
The bottom end felt more responsive though but not torquier.
From memory the dyno curve looked exactly the same as with the 1 /3/4 size headers.
Maybe now with a more appropriate camshaft with better timing events it will be even better.
As I stated earlier, I gained no torque but i did gain 1.5rwhp up top.
The bottom end felt more responsive though but not torquier.
From memory the dyno curve looked exactly the same as with the 1 /3/4 size headers.
Maybe now with a more appropriate camshaft with better timing events it will be even better.
LS3 heads suck on the exhaust side. I think they need all the help they can get on the exhaust side getting the air out the motor using a set of 2 inch headers. Ive seen bolt on LS3 even benefit going to a 2 inch header from a 1 7/8 inch header. On the dyno they was neck to neck to around 5200 rpm and the larger headers started to show a gain. I think by you running a stroker the 2 inch headers would be a no brainer but then again WHO KNOWS?
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#METHINKINGOUTLOUD
LS3 heads suck on the exhaust side. I think they need all the help they can get on the exhaust side getting the air out the motor using a set of 2 inch headers. Ive seen bolt on LS3 even benefit going to a 2 inch header from a 1 7/8 inch header. On the dyno they was neck to neck to around 5200 rpm and the larger headers started to show a gain. I think by you running a stroker the 2 inch headers would be a no brainer but then again WHO KNOWS?
LS3 heads suck on the exhaust side. I think they need all the help they can get on the exhaust side getting the air out the motor using a set of 2 inch headers. Ive seen bolt on LS3 even benefit going to a 2 inch header from a 1 7/8 inch header. On the dyno they was neck to neck to around 5200 rpm and the larger headers started to show a gain. I think by you running a stroker the 2 inch headers would be a no brainer but then again WHO KNOWS?
But after going from 1 3/4 to the 1 7/8 size I gained virtually nothing.
And this was with a re tune too.
Maybe the 1 3/4 size were a really good design to begin with.
They were one of the best in the country.
Because my engine only revs to 6200- 6300 there might be a lot more gains to be had when the engine spins up closer to 7000 rpm where the larger headers might shine.
Will need to wait and see.
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Yeah I know.
I have been watching a lot of car videos on YouTube and how come in a BMW M5 or Mercedes AMG they all shift at max hp?
They don't rev above their max HP rpm.
I saw an Aventador too. Same story.
Maybe in racing it's different.
I have been watching a lot of car videos on YouTube and how come in a BMW M5 or Mercedes AMG they all shift at max hp?
They don't rev above their max HP rpm.
I saw an Aventador too. Same story.
Maybe in racing it's different.
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You not taking advantage of the LS3 if you only revving the motor and shifting below 7000 rpm. LS3 heads love the 7000 plus RPM rpm range and you should take advantage of it. How you think NavyBLUE and BIG Hammer making big power out those two motors? They revving the hell out those motors.
Originally Posted by bortous
Yeah I know.
I have been watching a lot of car videos on YouTube and how come in a BMW M5 or Mercedes AMG they all shift at max hp?
They don't rev above their max HP rpm.
I saw an Aventador too. Same story.
Maybe in racing it's different.
I have been watching a lot of car videos on YouTube and how come in a BMW M5 or Mercedes AMG they all shift at max hp?
They don't rev above their max HP rpm.
I saw an Aventador too. Same story.
Maybe in racing it's different.
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You not taking advantage of the LS3 if you only revving the motor and shifting below 7000 rpm. LS3 heads love the 7000 plus RPM rpm range and you should take advantage of it. How you think NavyBLUE and BIG Hammer making big power out those two motors? They revving the hell out those motors.
What I mean is, if your camshaft for example makes peak hp at 6300rpm and then begins falling off why rev the engine any higher?
The BMW M5 peaks at 7100rpm and this is exactly where the shift happens. Right on peak power.
No sooner no later.
Same with the e63s AMG.
I'm revving my engine to 7000rpm this time because I finally have a camshaft that will allow.the engine to make power there.
Can't wait
I peak at 7K and shift at 8K. On my 346, I shifted at 7700. Made peak around 6850.
Your total gear multiplication results in higher total torque in the lower gear for a bit past peak. Here's the math using my 346:
6900 RPM in first gear = 412 lbs tq x 2.66 first gear x 4.30 rear gear = 4712 lbs torque at the pavement
Gear split drops to 4600 RPM on the upshift to second.
At 4600 RPM, I was around 420 lbs of torque, but give it the benefit of the doubt and use the peak torque number of 436 on the upshift x 1.78 x 4.30 = 3337 lbs torque at the pavement.
So on the upshift, I lose 1400 lbs of torque. On a 28" tire, that's 50 mph.
If I rev it out instead and shift at 7700, even if torque drops to 300 lbs at the motor, at the pavement, i get 3430 lbs torque. When I upshift, I land on 5150, which is right where I made peak torque, and ride that torque curve down again. On a 28" tire, that's 56 mph.
So from 50-56 mph, the car accelerates faster, AND I don't have to back-build torque by landed behind the torque peak, so the car starts the next gear right at peak acceleration.
On an auto I'm sure these calcs are a bit muddier, but on a stick, it definitely works exactly as described. Most of the benefit of a big cam is power past peak, not power before peak.
Your total gear multiplication results in higher total torque in the lower gear for a bit past peak. Here's the math using my 346:
6900 RPM in first gear = 412 lbs tq x 2.66 first gear x 4.30 rear gear = 4712 lbs torque at the pavement
Gear split drops to 4600 RPM on the upshift to second.
At 4600 RPM, I was around 420 lbs of torque, but give it the benefit of the doubt and use the peak torque number of 436 on the upshift x 1.78 x 4.30 = 3337 lbs torque at the pavement.
So on the upshift, I lose 1400 lbs of torque. On a 28" tire, that's 50 mph.
If I rev it out instead and shift at 7700, even if torque drops to 300 lbs at the motor, at the pavement, i get 3430 lbs torque. When I upshift, I land on 5150, which is right where I made peak torque, and ride that torque curve down again. On a 28" tire, that's 56 mph.
So from 50-56 mph, the car accelerates faster, AND I don't have to back-build torque by landed behind the torque peak, so the car starts the next gear right at peak acceleration.
On an auto I'm sure these calcs are a bit muddier, but on a stick, it definitely works exactly as described. Most of the benefit of a big cam is power past peak, not power before peak.
