Boost Leak

[SHIFT_240sx]

so i was participating in my first pca event when i noticed my car was making a high pitched squeek or whine at WOT, i checked my boost gauge and at WOT i was only hitting 5psi instead of 7psi, i tried to reach 7psi on a straightaway but after 3 seconds of trying i couldnt do it so i let off and signaled i was getting off the course. I let the car cool down for about 8 mins and then shut it off for another 15 and then decided to drive home. car felt fine, idled perfectly, even had nice pickup but it just would not hit 7psi and when i tried, the high pitched whine was there, so i stopped trying and just drove to work. i just replaced the gasket that goes between the manifold to the turbo, my intercooler pipes seem to be fine and nothing seems loose around that area, i didnt really push the car all that much and a never reached 100 on the track, but i know for sure im leaking boost from somwhere, anyone have any ideas on where i should check?

[Nicen96]

maybe check for some vaccum leaks

[SHIFT_240sx]

i have a vac line that goes to my carbon canister from my TB that is hissing but the last time i tried to plug it, the car would just shut off and have horrible idle.

[Vanguy]

In my time with the SR20, I've had both intake and exhaust leaks. Intake leaks usually just sound like hissing and the car is always slow, the MAF counts too much air and the car is a dog. Exhaust leaks have the screeching you're talking about, there aren't any sensors that are directly affected by this leak so the car will go as fast as the boost its still capable of, but as you noticed, the boost isn't all there. If the car can't do better than 5psi, your leak is pretty big. if its exhaust, you should be able to hear the engine popping and being generally loud even off boost. If you're sure there is no exhaust leak, you should get/make a boost leak tester like they sell at siliconeintakes.com