Thread: Dual Charged GTP

IIRC Zooomers 97 GTP ran 9.7ish quarter mile times and around 140ish mph. Its been a few years since these numbers were produced but Im pretty sure he picked up 1 full second and almost 20mph by adding the turbo to the car. I am planning to do this on my rwd L67 Cutlass soon.... if I get some free time in the near future lol. I am using a T70 turbo in my setup and I believe Zooomer told me a long while back that going big on the turbo was ok, especially since you have the supercharger making instant boost and keeping the exhaust housing on the big side would help out since turbo lag wasnt really a concern and it will make more topend power. There are a few others that have tried this though I have never seen anyone else with numbers.

I'd love to do this! Wish I could setup something like this myself, it would be challenging. Most likely it would require dual intercooling to work right. For me it probably wouldn't be a good idea because the bumper support would have to go and more extensive tranny work would be needed too....

A turbocharger heats up the intake charge more than a supercharger would. Both of them is insane and you'll knock so much you would probably blow the motor. You'd want to cool the air after the turbocharger (air to air intercooler) then cool the air after the supercharger (water to air intercooler) for the best bet at not grenading your motor.

To go twin charged and make it efficient, I would have to say you really need to take the M90 to it's limits first. Then I think zzp says a minimum of a 67mm turbo is needed when going twin charged. The benefits of twin charged would be no turbo lag, as the m90 is used and then after the turbo spools up, electronics will open the supercharger bypass. You would need a intercooler below the supercharger as the M90 is still producing hot air.

I would stay away from cartuning as they are not experienced in this area and I think special exhaust work is needed.

You would probably need #60 inj., unique pcm work done, stg 2-3 intercooler setup, front and rear powerlogs, stattama turbo crossover t4, a bigass turbo, a air/air intercooler, a cam, and a lot of extras.

And a transmission with $800 1" chain, probably $3500+ tranny rebuild altogether.

I'm definately considering this option of going twin charged. I have been doing my homework on it, and my setup would be ideal for this. All I would have to do is upgrade to the GMR 1" chain and buy the twin charged setup. Oh...axels would be a must too! I already have ZZP stg 3 ic and the porting on my SC is already ideal for this. I would just bore the bypass hole a little bigger and install a bigger plate. I really want to do this setup. T70 as well here.

1 thing I would like to try thought is different cams. I have the XPZ right now, and used to have a thrasher race cam. Everybody stated that you would have to have a huge blower for the Thrasher to perform and the twin charged application will certainly give enough boost. I'm just wondering how well it would work with this application. The Thrasher Cam sounds the best of any cam I have heard in a GTP by far!

Originally Posted by FoSHO99

To go twin charged and make it efficient, I would have to say you really need to take the M90 to it's limits first. Then I think zzp says a minimum of a 67mm turbo is needed when going twin charged. The benefits of twin charged would be no turbo lag, as the m90 is used and then after the turbo spools up, electronics will open the supercharger bypass. You would need a intercooler below the supercharger as the M90 is still producing hot air.

Ive never seen an application on any car that opened the bypass once the turbo was spooled. Most of the time people just cram the air through the rotors, as spinning rotors are less restrictive then your dime sized bypass valve. Its a good idea though. But running a small pulley then opening the valve would still cause alot of parasitic loss from spinning the blower so fast.
I would probably just run a large pulley like a 3.4(4 psi) or 3.2(6psi), depending on how much lowend grunt i wanted, and then turn the turbo up accordingly.

Originally Posted by TheRealKoop

Ive never seen an application on any car that opened the bypass once the turbo was spooled. Most of the time people just cram the air through the rotors, as spinning rotors are less restrictive then your dime sized bypass valve. Its a good idea though. But running a small pulley then opening the valve would still cause alot of parasitic loss from spinning the blower so fast.
I would probably just run a large pulley like a 3.4(4 psi) or 3.2(6psi), depending on how much lowend grunt i wanted, and then turn the turbo up accordingly.

I would say the electronics the are used on a twin chared set up would have to read a certain amout of boost pressure before the blower from the turbo and then open up the bypass valve. Once they bypass is open, the air will flow down there and some past the rotors as well. Once the bypass is open, the S/C will no longer be making boost, it should just be generated from the turbo and the s/c should be acting like a pump.

Would definantly work.

Yeah, and I think they recommend the 3.8 pulley for twin charged, when everything does get spooled up you don't want any extra heat created or hp loss from a small pulley. I wonder what the dyno charts would look like from this...