Turbo question
10-14-2004, 02:23 PM
#1
Turbo question OK guys... I think I am going to mimic the STS kit and make my own for my car. The question is, which turbo/wastegate should I get. Here is a breakdown of my buildup:
383 LT1 4 bolt
3.75" Cola Crank
5.7" H beam rods
Forged JE Pistons 8.75:1
Ported AFR 210's w/ GTP stg 3 Ported Intake and Monoblade
Custom Cam
Jet Hot LT's w/ Mufflex y-pipe and single cat before the turbo
I would like to run 8psi on the street and 15psi at the track. I just bought an OBX FMIC and I have alky setup to spray infront of the TB. I want to make as much power as possible while keeping lag down. I am thinking full boost around 2500-2800rpm. I was looking at compressor maps for the T-70, T-76, and T-88. It seems as though the T-76 will keep me in the efficiency range for my whole rpm band (low boost and high boost situations). Will I be able to make 750rwhp with the T-76 and will it have some serious lag? Also, since its rear mount, is there a trick to minimize lag, like intake piping having a smaller diameter, or exhaust piping being smaller. Also, which wastegate should I get (38mm, 50mm,?)? Thanks for all the help.
Jon
383 LT1 4 bolt
3.75" Cola Crank
5.7" H beam rods
Forged JE Pistons 8.75:1
Ported AFR 210's w/ GTP stg 3 Ported Intake and Monoblade
Custom Cam
Jet Hot LT's w/ Mufflex y-pipe and single cat before the turbo
I would like to run 8psi on the street and 15psi at the track. I just bought an OBX FMIC and I have alky setup to spray infront of the TB. I want to make as much power as possible while keeping lag down. I am thinking full boost around 2500-2800rpm. I was looking at compressor maps for the T-70, T-76, and T-88. It seems as though the T-76 will keep me in the efficiency range for my whole rpm band (low boost and high boost situations). Will I be able to make 750rwhp with the T-76 and will it have some serious lag? Also, since its rear mount, is there a trick to minimize lag, like intake piping having a smaller diameter, or exhaust piping being smaller. Also, which wastegate should I get (38mm, 50mm,?)? Thanks for all the help.
Jon
10-14-2004, 02:33 PM
#2
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Rear mounting a T76 will have some pretty big lag. Its bad enough with the GT67. The 76 depending on the version itself will support 750rwhp. On a conventional setup a 76 doesn't hit full boost till about 3500-4000 depending on the combo. Wastegate, well that depends on the amount of boost you want to run. The lower the boost the larger the wastegate. Don't get suckered in to you need a HKS 60mm GT gate since you are making X amount of hp. Wasegates should not be rated for HP.
10-14-2004, 03:07 PM
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Originally Posted by JZ 97 SS 1500
Rear mounting a T76 will have some pretty big lag. Its bad enough with the GT67. The 76 depending on the version itself will support 750rwhp. On a conventional setup a 76 doesn't hit full boost till about 3500-4000 depending on the combo. Wastegate, well that depends on the amount of boost you want to run. The lower the boost the larger the wastegate. Don't get suckered in to you need a HKS 60mm GT gate since you are making X amount of hp. Wasegates should not be rated for HP.
10-14-2004, 04:47 PM
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Surge and lag are 2 different things. As for GT67 on a LS1 rear mount, their is a dyno sheet around here, I will dig it up. What it showed was the GT67 not spooling till around 4000 or so..which is horrible for a 346 LS1 motor. Also when people refer to spool, full spool is peak torque. So if someone tells you they are spooling at 2000rpms....BS, maybe positive manifold pressure, but not full boost.
As for the 76 spooling in the rear, let me do some calculations and see what I can come up with. We are working on doing turbo testing ourselves...so hopefully we will put an end to all the turbo BS and have some concrete proof with variable inlet temps and such.....
Jose
As for the 76 spooling in the rear, let me do some calculations and see what I can come up with. We are working on doing turbo testing ourselves...so hopefully we will put an end to all the turbo BS and have some concrete proof with variable inlet temps and such.....
Jose
10-15-2004, 07:14 AM
#7
Originally Posted by JZ 97 SS 1500
Surge and lag are 2 different things. As for GT67 on a LS1 rear mount, their is a dyno sheet around here, I will dig it up. What it showed was the GT67 not spooling till around 4000 or so..which is horrible for a 346 LS1 motor. Also when people refer to spool, full spool is peak torque. So if someone tells you they are spooling at 2000rpms....BS, maybe positive manifold pressure, but not full boost.
As for the 76 spooling in the rear, let me do some calculations and see what I can come up with. We are working on doing turbo testing ourselves...so hopefully we will put an end to all the turbo BS and have some concrete proof with variable inlet temps and such.....
Jose
As for the 76 spooling in the rear, let me do some calculations and see what I can come up with. We are working on doing turbo testing ourselves...so hopefully we will put an end to all the turbo BS and have some concrete proof with variable inlet temps and such.....
Jose
230/244 .598/.613 116 + 4
It was designed for a SC, but after speaking with the person that ground it for, he stated that this cam will make peak power/tq lower in the rpm band versus a 230/230 .598/.598 116 (my other choice). I would think a cam that makes power sooner will also help the turbo spool faster? Maybe I am wrong to think this?