ok, so i have this boost issue. boost spikes to 24 and dips quickly down to 18. by the way, i'm trying to tune at 28psi on a green turbo on 100 octane. i had a shop look at it. the guy has an evo too and he says that something isn't right. i've already had some dyno shops check it out. looked for leaks in the boost system and did leakdown test. leakdowns were 4-5% for each cylinder and the boost system found no leaks. what else could be wrong? we switched out the bov's during the dyno and nothing changed. i'm going to try a different boost controller but until then, does anyone have any other ideas? by the way, the guy trying to tune my car logged the boost with his tuning stuff (i don't know what kind of things he used).

 

Logged boost??? Do you have a JDM MAP sensor??? If the answer is no, then your tuner can't be logging boost, unless he hooked up GM MAP sensor or something similar to your car.

 

well, he just hooked up a vacuum line and tapped it into one the the other intake manifold lines and logged it that way. obviously boost is falling quickly and not holding, not even tapering slowly therefore the torque curve fell off drastically. peak boost, it made 327 trq @ 4000rpms and fell off from there making about 250 trq @ 6700 rpms.

 

so i changed all the clamps back to worm drive clamps. i had t-bolts before this. i thought it might be the problem but NO. i am going to try my own boost leak test today. i'll post the results.

 

wastegate not pulled tight?

 

check if the wastegate is adjusted correctly because i just had an issue with mine and it had to be adjusted, go to forcedperformance.com and theres a video on how to properly adjust it

 

i was gonna say wastegate also

 

well, i just bought a high press wastegate actuator assembly today and overnighted it! haha. will try it tomorrow and post results. i guess i totally forgot about the wastegate!!!!....at least until you guys posted it up here in this thread.

 

well gl with that, if its not those could the turbo itself have some sort of leak in the housings? it has happeend before. also are you boost leak testing with the TB open? if your leak is lets say the manifold and the head, then a booost leak test up to the TB wouldnt show anything is wrong.

 

i've taken off the upper intercooler hose and tested the throttle body and the intake manifold. there were no leaks. also, leakdown showed that each cylinder were 4-5%.

 

ok so i got the problem fixed. it was the wastegate. i've already tried tightening the wastegate arm. don't work, so i replaced the arm with a high press one from forced performance and it fixed the problem. according t my gauge, it now only tapers about 2psi instead of dipping super fast down to 18 psi. now it goes from 25 down to about 22/23. i can now turn it up to 28psi and tune it from there. we'll see what power the green makes with minimal mods!