I have been out of the game for a couple of years and am planning on some conservative upgreats on my built powerlab G35 to increase the whp. I am looking at the following options: upgrading my fuel system to running e85 and retuning, Increase Meth flow, retuning and 3.5-4 inch catback exhaust and/or possible replacing the GT35r with an 6466 turbo and retuning. I am at ~525 whp and would like to achieve 575-600 whp. Also planning on adding an 1/2 plenum spacer to help. Any advise would be appreciated.


PS: build revup motor, 8.5 compression, JW S7 cams, stock intake, Haltech, Powerlab kit with gt35r turbo with 1.06 hotside, strup headers with hks dual exhaust, AEM meth kit spraying 1000cc/min

 

just run e85, take wastegate line off and lay on the timing.

that will get you 600whp

 

Yup, all you need is E85 and about 16-17psi to crack 600whp on a PowerLab GT35R kit.

 

What size injectors are need? Also, My car ran out of steam at 16 psi with high level of back pressure. Would increasing the exhaust size help? I am running a 3 inch into dual 2.5 exhaust currently.

 

Just get a T4 .96 a/r turbine housing on any of these turbos (6266/6466/6766), and make that power on pump without any issues.

 

By the look of things, I don't think a t4 flange will fit without some major mods or losing the ac. How about a 6766 with the 3 inch vband inlets? Is the back pressure stopping the turbo from making power pass 16 psi or is it the turbo itself. If it is the high backpressure, would running a dual three inch exhaust help?

 

Back pressure refers to the exhaust pressure before the turbine...so no matter how big your post turbine exhaust is, you will see the same problem.

The only way to solve it is to use a T4 turbine housing. You can keep everything else the same on the kit, as it will support 600+whp.

I think Momentum was able to make around 600whp (on a DJ) with a Tial 1.06 V-band turbine housing, so you may want to look at that option.

Using a 6766 with a .82 a/r V-band (only a/r available with the V- band from Precision) will not get you anywhere.

 

Here’s my car at 14 psi on pump gas (91 octane) vs. 16 psi on E85:



Only difference is fuel (fuel system’s been upgraded accordingly as well…)

The car’s running the original GT35R with a 1.06 Garrett T3 exhaust housing and stock exhaust manifolds. I’d just throw more pump, injector, and E85 at your car before you touch the turbo.

 

What sizes injectors and pump are you running? Also does the vband flow better than the t3 housing? I am only looking for an 50-75 whp bump.

 

I'm just running a CJM stage 1 RFS, DeatschWerks 1000cc injectors, and Walbro 485 pump. Not sure about housing flow through... but you should definitely see the extra 50-75whp with just E85.

 

ya E85 will be able to run MBT which could be 10-20* more timing depending how much timing you run now.

I think that the T3 flange is bigger than the v-band. There are supras running the T3 Super99 turbo making into the 7-800s.

Realitically, i'd put on a 150$ exhaust back pressure sensor way before you start messing with a new turbo.

 

If I decide to go with E85 will I have to do a complete retune? I have the older red Haltech. I don't think I have E85 sensor capability.

 

I have the cjm stage 1 kit, would I need to step up to the stage 2 and could I run my 340lp pump. Also, since I am running meth, should I keep it or remove it? Finally, How much gain, with E85, would I see since I am currently using 93 with Meth?

 

Yeah, you'll need a full retune... a CJM stage 1 RFS should be enough, not sure about the pump, I picked up a Walbro 485 to be safe, it was $150. You won't need the meth if you're running E85... I'm not sure about the gains from pump and meth vs. E85, maybe str8dum1 might have had experience with both...

 

I know zach711f on there has the powerlab gt35r and makes 622'ish on E85. Not exactly sure on boost levels.

 

on E85 you could run that turbo at full tilt and never worry about knock. You can also tune the timing to MBT.

I'd never try either of those on a pump gas/ meth injection tune.

The red box haltech would be kinda a hassle as you'd need almost 3 tunes. Pump gas, E85 and some where in the middle.

 

I would just get the T4 turbo and get your target HP on pump gas. No worries about fuel availability, tune/maps or meth. Make it simple, and be done with it.

 

I am in a similar situation.
weisco 8.8:1 pistons, E85, 35R turbo, not sure if .82 or 1.0 rear, T3, 1000cc Dw injectors, stage 3 CJM kit, 500HP and tuner says injectors are maxed out...60psi base pressure, 80psi full boost. HKS external wastegate at 14psi, 3" exhaust fujitsuo.

Do i get the Blackops / FID stainless Bosch IV14 1200cc or 1400cc injectors and push more fuel at it? Tuner also said before i changed wastegate vac lines that back pressure was an issue but i changed according to this.
http://www.turbosmart.com.au/wp-cont...Y_12_rev_2.pdf

from Two port connection Method (2) (For obtaining maximum boost pressure on your turbo system)
to Two port connection Method (1) (For controlling boost on a turbo system with high back pressure)
as was getting boost spike...

any suggestions on injector size and other tips? OP hope the pdf helps you out on the back pressure.. i only got a 460 to 500Hp using 98 pump from pump to e85 ..

 

You’re running the HKS single turbo kit, right? Did you upgrade to the GT35R?

 

Yes but upgraded the 3037 T2 to 35r T3 with .81 or 1.0 rear. im asking the guy which it is. what do you suggest for me re injectors ?