Last week after installing a Greddy blow off valve - I noticed that my car would leak boost at high rpms (over 5300). It sounds kind of like a loud suction and boost will drop to about 14psi before redline in first and second gear. I cant even make it through 4th gear up high and barely to redline in 3rd.

So I put the stock blow off valve back in...it still did it. Then I removed and checked all intercooler hoses, intake hose, boost lines and there were no rips or tears in any of them and I made sure they were all tight...took it for a ride and it still leaked. And yes, the bov is installed correctly. I also have a HKS EVC installed (set @ 19.5psi) so I thought the wastegate vaccum line may be leaking (unlikely considering I get full boost till 5300rpm without leak) and causing the wastegate to close...I replaced the vaccum line and it still does it. I even tried reseting the ECU with no luck. I dont know what else to do before I bring this back to stock and take a visit to the dealership. Any Ideas? Thanks in advance, Zach

 

Anyone?

 

Check your intercooler hoses and the intermediate pipes.. also double check to make sure the BOV isn't installed backwards, you don't want to miss the obvious.. a lound suction noise is something we hear with an open air filter.. so check the MAF sensor and the pipe connecting it to the turbo, it could be leaking too.. But if your not making max boost, and your certain its not the BOV or boost controller, I'd look at the intercooler piping, if you had to remove it for any reason, its possible the hose is cocked and not sealing completely. Also look for something as silly as if you installed a boost controller that recommends using a vaccum source/boost source other than the source on the turbo housing, that you capped the original source, and that it didn't pop off..

 

i think my car does the same thing but its stock.
it sounds like a hissing noise and doesnt pull as much as it did before.
did you find out what the problem was ?

 

This is driving me crazy - it should be such a simple problem. I know its a leak and I just inspected all my hoses including the intake hose on the turbo and intercooler hoses and im positive none of them have leaks. It may be that one of the intercooler hoses is blowing off but i've taken them off twice and made sure they were as aligned as possible. The bov isn't backwards and the HKS boost solinoid is installed correctly. I just dont know - it sounds exactly like a intercooler hose leak/blowing open at high rpm.
Since I had the intake hose off, I hooked up the factory boost control solinoid and removed the HKS (its much easier to get to the vac hoses with it off) incase I have to take it to the dealership. Maybe I should just get some samco intercooler hoses and a intake tube instead because I really dont feel like taking everything out of my car to bring it to the dealership just to find out one of the intercooler hoses isn't sealing properly. Thanks for the reply - i'll update later tonight when im done putting it back together. -Z