I recently turbo'd a GSR with a T28 homemade it. It has a starion/conquest FMIC and 2.5" piping. Well my question is I can't get this to hit 10psi (stock wastegate psi) until last night when I unhooked the vacuum line from the turbo to the wastegate and it hits and holds 10psi fine. Any ideas why this is? That really makes no sense.... Also this turbo should really be hitting 10psi alot earlier than it is. It hits 10psi about 5K on a GSR...
Any help
Thanks guys!
~Will

 

what turbo manifold you using? stock exhaust/cat?

 

you ***** fucked up. My weedwacker could spool a t25. It has no place on a gsr engine. But to attempt to help you, check for boost leaks and try replacing the actuator

 

Right now it has a log manifold on it. and it is just running open downpipe out the side of the bumper. I have done various charge pipe testing with my compressor and everything seems to be ok. I have T bolt clamps on just about everything too.



We went with a T28 because of the low end torque, which isn't happening right now.

I forgot to mention that the turbo was freshly rebuilt absolutely no shaft play...

 

try replacing the wastegate actuator

 

if its only holding 10 psi with the wastegate unhooked - something is wrong... it should be goin to like 20. maybe a boost leak.

 

IMO a t28 is kind of small for a GSR...
Unless of course if it's a GT2871R with the 0.86 a/r turbine !! (able of 450 HP!!)
But if it's an old style garrett T28, I say no more than 5 psi on a GSr and still, this turbo will die on you from overheating in no time.

 

thats is way to0 small turbo to use on a GSr,.
Its the common problem with T25 and t28 Just hammer the actuator back to tight it up il be ok,,

 

I had this problem with my T-25 on my D. My air filter setup was the issue. I had a cone filter on it that had kind of an inverted cone on the top of the filter. The pipe I was using for the fillter side had slid over the inverted portion of the filter thus helly restricting the flow of air. It would take forever to get to 8psi, but once it got there it held, whether or not I had a vaccum line hooked to the accuator or not. I Left the filter off one day and noticed the severe difference in boost and I knew I had solved my problem.

Also, hello to a fellow High altitude boost freek. Come to the TC Performance Dyno day on Sunday the 13th. TCPerf.com

 

i had the same problem with the air filter sliding over the intake pipe!!!!

It took me a week to figure out why the damn thing wasn'T boosting anymore!!! :1