boost decreases while RPM increases!?!?!?!?!?!
 

okay...when i first put my turbo together like 4 months ago i didnt have an intercooler and the car boosted at 5 PSI all the time,then i added the intercooler and put the boost controller up to 6psi and the god damn thing reaches full boost at 4000 rpm then at 6000 rpm, the boost starts lowering and by the time i get to 8000rpm im boosting at 1-1.5 PSI and its not even enough to make my BOV work, i thought it was my boost controller but i took it off and now its getting even less boost and doing the same thing, should i like use another vacuum source for wastgate other than the one thats on the the turbo? like one around where the intake manifold is, will that correct the problem?

Re:boost decreases while RPM increases!?!?!?!?!?!
 

oh...and its a T3 which i guess is small for my high revving engine, but if my friends T25 can boost his eclipse at 15 PSI all the way to 7000rpm, then my T3 which is bigger should be able to push 10PSI all the way up to 8000rpm.

Re:boost decreases while RPM increases!?!?!?!?!?!
 

maybe your intercooler is leaking. or some of your charge pipes can't hold that pressure. but if it worked before its probably your intercooler that can't hold the pressure... is it a junkyard intercooler?

Re:boost decreases while RPM increases!?!?!?!?!?!
 

intercooler has to be leaking.

Re:boost decreases while RPM increases!?!?!?!?!?!
 

yeah you probably dont have a hose clamp tightened down enough. also, a t3 is plenty big for your little b16. also, that little ass t25 will not boost to 7k on a stock 2g. the thing dies out around 6-6500 rpms on a stock 2g. with mods it'll keep boosting higher...but it has no god damn pull up top. the powerband on that turbo on a 2g is from around 2500-5500 rpms...

Re:boost decreases while RPM increases!?!?!?!?!?!
 

Check for leaks wherever you have your intercooler piping clamped with a rubber connector. Sometimes those little bastards don't seal right or they tear through, and you won't be able to tell unless you look really really close.

Re:boost decreases while RPM increases!?!?!?!?!?!
 

it cant be the intercooler because its only when i get past 6000 rpm, it holds the boost from 3800-6000, its only past that, its like the turbo cant spool as fast as the engine can go, but maybe you guys are right, damn this sucks, i wish i just new what it ------- was, blastphemy.

Re:boost decreases while RPM increases!?!?!?!?!?!
 

I had a similar problem to yours. everytime i hit 8 psi, it would shutdown...I added an MBC and set it to 6 psi...now it runs like a champ...sure its running lower max boost, BUT steady...and I LOVE it.

chris

Re:boost decreases while RPM increases!?!?!?!?!?!
 

check out the posts over at H-T, alot of b series guys running t3 setups had that problem. before an intercooler they boosted like champs, but then after the intercooler install boost dropped off, with the higher revving b16 motor, the t3 turbo ( im assuming its the junkyard saab .42 .48 deal) isn't efficient at that level. it can't flow that much.

Re:boost decreases while RPM increases!?!?!?!?!?!
 

I'm gonna instal a 60 trim nissan 300zx t3, will that one be efficient at high rpms? i have the same car 99 civic si b16a. i wanna boost like a champ :o