Crazy Noise while boosting. No boost leaks anywhere

[Rollinon18z]

Very strange noise like squealing belts while under boost. Only while under boost and above 5 psi. No boost leaks anywhere. Tripple checked even fixed the pinhole leak that was coming from the BOV. I have a BBK throttle body and that was leaking so I disassembled it and put new orings on the shaft of the plate. Added some great to make sure everything went back together smoothly. Now It will only boost to 12-14 psi and make a crazy squeal like an animal is getting killed in the engine bay. Have brand new belts and I checked to make sure tension was ok on all of those. But seeing as I can rev to 8k in neutral and it doesn't make a sound like that I am guessing it is not that at all. I checked my wastegate to make sure proper assembly was done when I changed diaphragm but everything seemed fine inside there as well. I am baffled and don't get it. Any insight or if anyone has had this problem before please let me know. (And it is not a grinding noise at all best way to put it is when you lake a blade of grass and put it through your thumbs and blow real hard!) Weird I know but best way I could figure I can describe it. And turbo is absolutely fine. Spins freely and no shaft play.Thanks Tim

 

[Dxc545]

You didn't say anything physically checking the compressor wheel for play. Mine made a noise going into boost, it was a kind of squeak/grinding noise. Turned out my turbo had play and was going bad.

 

[Rollinon18z]

Oh my bad bro. I did check the turbo and she spins freely. I can spin it with my fingertips and has no side to side shaft play. I am at a loss right now. I was hoping I can find an answer or a place to start here so I don't have to drive it 180 miles to pay $160 just to have it diagnosed by M.A.P. Thanks for your reply

 

[Dxc545]

ya if you can rev it freely but has problems under boost its definitely turbo related. does it make noise accelerating without going into boost?

 

[Mark4g63t]

How high did you check your boost leak test too? Sounds like a boost leak.

 

[Rollinon18z]

The car does not make that noise going into acceleration. Only after 5-7psi does it start to make that sound. I set my regulator at 25psi when I checked for boost leaks. That's all I run is 25 psi or just below that. I will try throwing another 10 psi and see if I come up with anything. But at 25 psi it makes no noise whatsoever. There is a little excess coming through the WasteGate but that is supposed to do that right? I have a 14.5lb spring in there so anything over that will exhaust right? Thanks for your replies guys. Any help is better than no help...