75/96/.90 low boost #s

R

redram04

New member
Joined
Nov 29, 2010
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534
So i am running a 75/96/.90 t4 on my 6.7, has a cam and ported head and is fueled by some 200% overs. The issue is, regardless of tune i can only make 40-45 psi and it never cleans up.

So where could i look to try and improve perf from this unit. Drive to boost is never over 1:1

Thanks
pulling my hair out trying to get thus thing to run better.
 
I think you need a larger aspect ratio on the turbine housing. That's alotta turbine for that exhaust housing.
 
I tried it with a 1.10 and it would only nake 30psi with about 17-20 drive.
 
If your sure there's no boost leaks...I'd think about stepping down in turbine size.
 
Never surges, hard to stay on top of it between shifts even when the next shift only drops to 2500 rpm.
 
Got a 75/96/1.10 i am gonna slap on friday and see how it compares, bponci you the man
 
DirtyMaxx03 said:
I think you need a larger aspect ratio on the turbine housing. That's alotta turbine for that exhaust housing.
Click to expand...

I agree with this. A 6.7, especially with that much injector, can handle a T-6 manifold/housing. Maybe go with the 1.1 T-6 housing.
 
Trying not to throw another manifold on it right now. Ill see how the smaller turbine does. Have to keep my eye out for a t6 manifold.
 
redram04 said:
Trying not to throw another manifold on it right now. Ill see how the smaller turbine does. Have to keep my eye out for a t6 manifold.
Click to expand...

I understand man, and I hope that does work for you. I just know my experiences running several 475/87s and a 476/87 both with 1.0 and .90 T4 housings on a 5.9 and 100% over injectors. That truck would spool and drive very well considering their size and just a basic smarty tnt-r tune. I could hold 60# of boost all the way down the track with drive hovering between 40-45#. I know your truck is much more capable than mine was.
 
Will do the swap, then go drive it on same tune. Hoping a smaller turbine wheel will be more responsive. This current wheel is a plain ol slug if you roll off the throttle at 2200 and back in it again.
 
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