Track Results of 2.5" insulated exhaust for rear mount setup
05-10-2007, 12:50 PM
#1
Track Results of 2.5" insulated exhaust for rear mount setup Few specs on the car and setup.
370 cube motor, 8.7:1 comp, 6.0 heads (no port work), z06 cam, Th400, Custom rearmount, ITS DBB T76 R trim .81 a/r. 4" downpipe.
Race Weight, 3850 with 1/2 tank(it's a pig
)
Density Altitude was 4700 (90 degrees at 9pm, suck)
I had my friend Jon fab up and install a new exhaust setup for my car from the manifolds to the turbo and wrap it with DEI header wrap. Had enough wrap to make it to just above the rear axle with 2 rolls.
Previously I had issues doing burn outs and spooling on the line. I had been running stock exhaust with hollowed out cats and insulated y-pipe. In order for me to cut good 60's I needed to have a very good burn out to get the exhaust hot so it would spool at the line. I would have to leave on 10psi to cut high 1.5x to low 1.6x 60's.
Last night was the first time at the track on the new exhaust and the results are great. My burnout time has gone from 10 seconds down to about 5 seconds due to the faster spool. At the tree I'm now able to spool and leave on green vs 1-2 seconds after green. The amount of boost need to get a good 60' has dropped from 10psi to 5psi because of the faster spool. The track prep was so so last night and I was spinning my way to mid 1.6x 60's.
My ET and MPH has improved quite a bit as well. Last night I was running off just my waste gate spring of 13psi. I was able to run 10.8-10.9 @ 126-127 once I figured out the launch. With better track prep and some more timing (was on my 91 octane tune) the car should be able to go 10.6s at this boost setting on a great pass. I was running 6.9-7.0 @ 101 in the 1/8th and had some detonation/tuning issues in 3rd gear and didn't have the laptop with... doh.
Next time out I'm hoping to be tuned for 100 octane and 18psi.
The car has an exhaust leak right now as well, but the spool is REALLY fast on the street, night and day compared to the previous exhaust setup. The boost hits VERY hard on the street. Previously it was a more gradual building of boost.
370 cube motor, 8.7:1 comp, 6.0 heads (no port work), z06 cam, Th400, Custom rearmount, ITS DBB T76 R trim .81 a/r. 4" downpipe.
Race Weight, 3850 with 1/2 tank(it's a pig
)Density Altitude was 4700 (90 degrees at 9pm, suck)
I had my friend Jon fab up and install a new exhaust setup for my car from the manifolds to the turbo and wrap it with DEI header wrap. Had enough wrap to make it to just above the rear axle with 2 rolls.
Previously I had issues doing burn outs and spooling on the line. I had been running stock exhaust with hollowed out cats and insulated y-pipe. In order for me to cut good 60's I needed to have a very good burn out to get the exhaust hot so it would spool at the line. I would have to leave on 10psi to cut high 1.5x to low 1.6x 60's.
Last night was the first time at the track on the new exhaust and the results are great. My burnout time has gone from 10 seconds down to about 5 seconds due to the faster spool. At the tree I'm now able to spool and leave on green vs 1-2 seconds after green. The amount of boost need to get a good 60' has dropped from 10psi to 5psi because of the faster spool. The track prep was so so last night and I was spinning my way to mid 1.6x 60's.
My ET and MPH has improved quite a bit as well. Last night I was running off just my waste gate spring of 13psi. I was able to run 10.8-10.9 @ 126-127 once I figured out the launch. With better track prep and some more timing (was on my 91 octane tune) the car should be able to go 10.6s at this boost setting on a great pass. I was running 6.9-7.0 @ 101 in the 1/8th and had some detonation/tuning issues in 3rd gear and didn't have the laptop with... doh.
Next time out I'm hoping to be tuned for 100 octane and 18psi.
The car has an exhaust leak right now as well, but the spool is REALLY fast on the street, night and day compared to the previous exhaust setup. The boost hits VERY hard on the street. Previously it was a more gradual building of boost.
05-10-2007, 01:31 PM
#4
Originally Posted by 98turbls1
Wow great news Zombie... Definitely keep us updated with all of the good news...Where is the exhaust leak or do you not know?? I bet once you fix that it'll spool even faster...
I don't know if I want faster spool lol, it's pretty brutal right now. I can definately spool a larger turbo. The only reason it's not rediculous on spool right now is because my stall is pretty tight upto 5psi, after that the boost gage is is a rocket and it's tricky to modulate. To go from 8-15psi it's probably .25 seconds. This tight converter lets me drive around nicely though. 45mph at 1700 rpms, no lockup.
After 5psi is when the boost "goes over the falls".
Last edited by Zombie; 05-10-2007 at 01:38 PM.
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05-10-2007, 02:53 PM
#8
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i remember when i had asked about reducing my exhaust to 2.5" from 3", that everyone that replied had said it would make no difference 
.... well this proves them wrong! i bet your power curve is now like mine!! 
here's my dyno graph:
https://ls1tech.com/forums/showthrea...light=sts+dyno
and here is my old thread about reducing the exhaust
https://ls1tech.com/forums/showthrea...exhaust+2.5%22
.... well this proves them wrong! i bet your power curve is now like mine!! here's my dyno graph:
https://ls1tech.com/forums/showthrea...light=sts+dyno
and here is my old thread about reducing the exhaust
https://ls1tech.com/forums/showthrea...exhaust+2.5%22
05-10-2007, 02:58 PM
#9
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Originally Posted by JD_Z28
Congrats on the new times Zombie.
I finally wrapped my exhaust and the difference is insane even with my .96 housing. The biggest difference is theres no lag between shifts anymore.
I finally wrapped my exhaust and the difference is insane even with my .96 housing. The biggest difference is theres no lag between shifts anymore.
Damn it i just noticed you've got a two step
05-10-2007, 03:25 PM
#10
Originally Posted by RooRnZ28
i remember when i had asked about reducing my exhaust to 2.5" from 3", that everyone that replied had said it would make no difference .... well this proves them wrong! i bet your power curve is now like mine!!
and here is my old thread about reducing the exhaust
https://ls1tech.com/forums/showthrea...exhaust+2.5%22
.... well this proves them wrong! i bet your power curve is now like mine!! and here is my old thread about reducing the exhaust
https://ls1tech.com/forums/showthrea...exhaust+2.5%22
05-10-2007, 05:33 PM
#12
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i like that. i would like to buy all the factory exhaust minus the special TRT i pipe, and see what the difference in spool would be. i know it will be better, but i wanna see for myself
