Why is TQ so inconsistant in FI setups?
so heres the breakdown basically:
99ss-t was 100% stock with a T76 , 10 psi made 531rwhp/534rwtq
robs was a 2001 100% stock (open exhaust) with a pte-63 534/687 w/ 9psi
tiago was forged bottom end and T72 615rwhp/613rwhq with 10psi
my guess its 99SS-T doesnt want to push the car too hard cause its stock and i believe he was have PCV problems at the time. Robs car prolli made what it did because it had an open exhaust which means really low restriction and backpressure.Tiago wasnt pushing the motor much either seeing as hows its forged,but he also may be running out of turbo with the T72 at over 600rwhp.I THINK a T72 is maxed out at about 800 crank hp,so its possible but i think he may have had room left.And none of these guys had a cam correct?
99ss-t was 100% stock with a T76 , 10 psi made 531rwhp/534rwtq
robs was a 2001 100% stock (open exhaust) with a pte-63 534/687 w/ 9psi
tiago was forged bottom end and T72 615rwhp/613rwhq with 10psi
my guess its 99SS-T doesnt want to push the car too hard cause its stock and i believe he was have PCV problems at the time. Robs car prolli made what it did because it had an open exhaust which means really low restriction and backpressure.Tiago wasnt pushing the motor much either seeing as hows its forged,but he also may be running out of turbo with the T72 at over 600rwhp.I THINK a T72 is maxed out at about 800 crank hp,so its possible but i think he may have had room left.And none of these guys had a cam correct?
what i dont understand is how does 99ss-t make 531 with a 10psi t76 and tiago makes 80+more rwhp with a t72 and 10psi with the exact same mods???? and then rob made 150lbs more rwtq over 99ss-t with 9 psi, open exhaust and a ls6 intake. they all have pretty much the same mods but the numbers are very different.
because the turbos are very different for starters....and 1 car is totally stock,the other had open exhaust(makes a big difference) and another is using not stock shortblock....its all about how efficient a setup is.
I don't think my turbo was anywhere maxed out, it had a 72mm wheel but it was huge physically, 5" inlet, 3.5" discharge, t4 flanged turbine, 0.96 A/R. Compressor was 0.75A/R if I recall.....
SSU'S Vice Mod
Joined: Jul 2004
Posts: 2,391
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From: Hazard Co. Maryland
Originally Posted by 30th t/a
what i dont understand is how does 99ss-t make 531 with a 10psi t76 and tiago makes 80+more rwhp with a t72 and 10psi with the exact same mods???? and then rob made 150lbs more rwtq over 99ss-t with 9 psi, open exhaust and a ls6 intake. they all have pretty much the same mods but the numbers are very different.
Those differences right there say one thing, which is what I said earlier, TIMING! Plane and simple. 1 degree can be as much as 20 horse on a boosted car, which makes a huge difference. 1 extra # of boost can also mean about 20~30 horse (depending upon who you talk to, weather conditions, ect). It comes down to what you want to do to push the envelope and how much risk you're willing to take.
LS6 intake has, I believe, a bit longer runner, which will make a HUGE difference. One thing I have learned over the course of reading the boards is, since boosted cars do not need to flow that air as fast as a NA car. There is no need to "pump" more air in or increase the velocity through a shorter runner since it's already pressurized. What is best is to have the ability to let that air conform down to the port size and flow the best and that will help you build some TQ up.
Keep reading, you're getting it.
Tiago, were you running a GT series compressor cover?
Originally Posted by Tiago
I don't think my turbo was anywhere maxed out, it had a 72mm wheel but it was huge physically, 5" inlet, 3.5" discharge, t4 flanged turbine, 0.96 A/R. Compressor was 0.75A/R if I recall.....
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I think teh main reason fo rthe difference is the radicalness of the tune as far as timing goes. I think that Rob was runnin a ton of timin where as i am runnin 13* of advance which is prolly 10 less then he was runnin. Rob was runnin that car for broke. They were trying to find the limits of the stock engine so i wouldnt doubt that they were on a extremely thin edge with most everything on the car. Timing, AFR, and what not.
I currently have teh exhaust of after the down pipe and it spools alot faster and feels alot faster at the same boost as it was before. So i cna only imagine what it would do with alot more timin adn the exhaust open like it is. GL man
John
I currently have teh exhaust of after the down pipe and it spools alot faster and feels alot faster at the same boost as it was before. So i cna only imagine what it would do with alot more timin adn the exhaust open like it is. GL man
John
Originally Posted by 2000 Tran Zam
Sometimes I see setups with similar matching rwhp and rwtq, and at other times i see 100 or more rwtq then hp.
Is there anything in particular that affects it? maybe certain cam specs bleed of enough pressure to affect hp, but not tq?
I'm not sure how its all connected, but its something interesting to examine...
Is there anything in particular that affects it? maybe certain cam specs bleed of enough pressure to affect hp, but not tq?
I'm not sure how its all connected, but its something interesting to examine...
It depends.
-AF ratio
-Backpressure
-Cam
-Engine compression
-Engine size
-Intake
-Exhaust
-Timing
-Cylinder bores
-Type of FI
Plus it's hard to get a decent torque reading on a Dynojet with an unlocked torque converter.
Originally Posted by Pro Stock John
Here's the answer...
It depends.
-AF ratio
-Backpressure
-Cam
-Engine compression
-Engine size
-Intake
-Exhaust
-Timing
-Cylinder bores
-Type of FI
Plus it's hard to get a decent torque reading on a Dynojet with an unlocked torque converter.
It depends.
-AF ratio
-Backpressure
-Cam
-Engine compression
-Engine size
-Intake
-Exhaust
-Timing
-Cylinder bores
-Type of FI
Plus it's hard to get a decent torque reading on a Dynojet with an unlocked torque converter.
Suspended Sponsor
Joined: Oct 2004
Posts: 371
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From: Just outside of Palm Springs Ca.
Originally Posted by 2001WS6Vert
I don't believe one degree would be anywhere near 20 hp.
-Bryan
Suspended Sponsor
Joined: Oct 2004
Posts: 371
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From: Just outside of Palm Springs Ca.
Originally Posted by GrahamHill
I would think the precision of the wastegate would allow for some change to wouldnt it? Agree, disagree?
This could also make a big diffrence, the efficiency of the boost controller or the ability to not bleed boost until the exact boost pressure is reached would build alot more torque.
-Bryan
10 Second Club
Joined: Apr 2002
Posts: 1,755
Likes: 2
From: Cincinnati, Ohio
Originally Posted by Race-Prep
I would have to say it definatly can be worth that much, we have seen here where the ability to add timing can gain as much as 100WHP!! I have seen it first hand.
-Bryan
-Bryan