Building a NASA ST2 Race motor. HP to weight restricted.
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Building a NASA ST2 Race motor. HP to weight restricted.
Good morning,
I did a search but did not come up with much, my search criteria may have been the issue but I figured I would post up.
Build is Gen III LS based. Running stock EFI and 60lb injectors
We have a hp ceiling of 400 whp.
We would like to make significantly more Torque than HP.
We chose heads valve train and shortblock for durability reasons more than anything.
Heads.
AFR 210 #1510
Stock rockers
Morel Link bar hydraulic roller lifter
Shortblock
Texas Speed 383
3.903 bore
4.00 stroke
-3 Wiseco pistons
6.125 callies rod
Head gasket is FelPro MLS
4.100 bore
.041 compressed
Camshaft is comp part #54-416-11 LS1 XR273HR-12
We made exactly 400hp and 400ftlbs and the curve is awesome.
I talked to Katech, they suggested bringing the RPM range down 1000 rpm, putting in a bigger cam and restricting behind the throttle body or in the intake snout somewhere, I am left wondering if we could have got more torque.
What do you guys think?
I did a search but did not come up with much, my search criteria may have been the issue but I figured I would post up.
Build is Gen III LS based. Running stock EFI and 60lb injectors
We have a hp ceiling of 400 whp.
We would like to make significantly more Torque than HP.
We chose heads valve train and shortblock for durability reasons more than anything.
Heads.
AFR 210 #1510
Stock rockers
Morel Link bar hydraulic roller lifter
Shortblock
Texas Speed 383
3.903 bore
4.00 stroke
-3 Wiseco pistons
6.125 callies rod
Head gasket is FelPro MLS
4.100 bore
.041 compressed
Camshaft is comp part #54-416-11 LS1 XR273HR-12
We made exactly 400hp and 400ftlbs and the curve is awesome.
I talked to Katech, they suggested bringing the RPM range down 1000 rpm, putting in a bigger cam and restricting behind the throttle body or in the intake snout somewhere, I am left wondering if we could have got more torque.
What do you guys think?
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sbc240z
97m3
97m3
Re: Building a NASA ST2 Race motor. HP to weight restricted.
I think I understand your point. Are you drive chain restricted? If not, you may be better advised to think in terms of a broad, flat horsepower curve. More torque at higher RPM is better as long as you don't exceed the HP limit.
Re: Building a NASA ST2 Race motor. HP to weight restricted.
Well, I was curious if the guys at Katech are on the right train of thought. Build the motor to make 500hp/ftlbs then restrict it down so it doesnt breath up top to take the peak off of the hp curve.
sbc240z
97m3
97m3
Re: Building a NASA ST2 Race motor. HP to weight restricted.
Almost all of them are 4.100
http://www.summitracing.com/search/part ... 4294918235
http://www.summitracing.com/search/part ... 4294918235
sbc240z
97m3
97m3
Re: Building a NASA ST2 Race motor. HP to weight restricted.
How much time/money do you want to put into this?
Instead of a "restrictor plate" you could go through the effort of filling the heads and intake to the exact size needed for your desired hp and torque peak.
You'll be able to get more power at a lower rpm this way (more torque), but it can be very labor intensive.
Instead of a "restrictor plate" you could go through the effort of filling the heads and intake to the exact size needed for your desired hp and torque peak.
You'll be able to get more power at a lower rpm this way (more torque), but it can be very labor intensive.
LOL, according to the post count I'm an "expert." The only thing I'm an expert at is asking questions.
Re: Building a NASA ST2 Race motor. HP to weight restricted.
IDk about building a high hp motor and chocking it down
you end up with no top end and no low end
I'd go for 400 hp as low as I could get it and flat to redline
you end up with no top end and no low end
I'd go for 400 hp as low as I could get it and flat to redline
Re: Building a NASA ST2 Race motor. HP to weight restricted.
With an ignition you could program could you pick up the bottom end then kill the top with timing?
Re: Building a NASA ST2 Race motor. HP to weight restricted.
Pulling timing up top is what we have done.
Right now in the Tudor series they have what would be 800hp engines choked down to dual 31(?)mm restrictors.
The engins make in the 500hp range and 600+ftlbs
Right now in the Tudor series they have what would be 800hp engines choked down to dual 31(?)mm restrictors.
The engins make in the 500hp range and 600+ftlbs
sbc240z
97m3
97m3
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Re: Building a NASA ST2 Race motor. HP to weight restricted.
First off have you any idea what the average rpm band is going be on the track, other wise how do you know where to focus your golds on!
You can cut a man's tongue from his mouth, but that does not mean he’s a liar, it just shows that you fear the truth he might speak about you!
Re: Building a NASA ST2 Race motor. HP to weight restricted.
Average rpm will be 4200-6500.
Which is what we shot for with the camshaft
Which is what we shot for with the camshaft
sbc240z
97m3
97m3