Whining noise when under boost?

[klh6686]

Hey how's it going everyone? I have a question, my bro's rb20 is making a whining noise that is seperate from the induction noise of the turbo, but we have diagnosed that it only occurs under boost. My first thought was the altenator, since mine whined before it went out, but as i said, he could rev the car w/o creating boost and it wouldn't whine, but as boost built, the whine built too. My second guess was the blitz intake filter, because the end kinda looks like a whistle, so we took the filter off and the car made the same noise. Now my guess is that possibly the bearings are going bad in the turbo. Do you guys think that could be the problem? it seems to boost just fine, but i guess we could take off the intake and see if there is any shaft play. If you guys have any ideas, let me know and maybe we can come up w/ something. li said, it appears to only happen under boost. Thanks.

[Slo_240sx]

Boost leak. Check all of your clamps and vaccumm lines.

[biglipzit]

Boost leak would make more of a wooshing noise. I think it is a turbo death whine which is the bearings going bad...

[Cornloaf]

make sure your turbo is tightly bolted to the manifold. I had a whistling noise, and i decided to replace my turbo, it wasn't until i started taking it off that i realized two of the four bolts were not even tight. i torqued them down and it was all better. Worth having a look.

[krayton]

make sure your turbo is tightly bolted to the manifold. I had a whistling noise, and i decided to replace my turbo, it wasn't until i started taking it off that i realized two of the four bolts were not even tight. i torqued them down and it was all better. Worth having a look.

good call. same to me. the whistling was coming from my gasket and the small crack.

otherwise im calling dieing turbo too.

[klh6686]

man is it ever so hard to diagnose sounds when you can't upload a sound clip, i don't even think i could capture the sound... its pretty faint but it doesn't sound like the clip of the deathwhine. It's more faint and it sounds more like the altenator whining or even the clutch slipping, but its not either. I guess we will check for shaft play and also take a look at all the bolts, but other than that idk what it could be. Thanks!

[JonPowell]

Pinpoint the sound in the engine bay....you need to find where its coming from to know what the possible problems may be.

[klh6686]

the only thing that is making it hard to pinpoint is it only occurs under boost, and you really have to rev the crap out of it in neutral to get any boost, which of course makes it harder to hear. We will try to pinpoint it the best we can, thanks everyone for the ideas!