I was driving home from the auto parts store just now, and I had an open straight away so I gunned it. Up in the higher RPM's, it suddenly started a high pitched whine. Anytime boost started ~1 psi, it wouls start whining. I thought maybe a vacuum hose popped off or something. Does anybody know what happened. I've been searching, and a lot of people blame excessive shaft play, but I can't imagine a turbo going bad so suddenly. HELP!!

 

check all the couplers for a boost leak

 

x 2

 

sounds more like a pinhole in a vacuum line. Check for a line that has been pinched under the manifold or pressure tank, bet it's a vacuum line with a small hole that's almost invisible upon visual inspection until you bend it at the hole! Have seen this happen several times
Art

 

Good time to try the old propane torch test, with the car idling use an unlit propane torch and run it over all the vacuum lines, the engine RPM should change when you get near a leak as the propane gets sucked in. The only other thing I could possibly think of is a damaged turbocharger, but you'd be losing boost from that probably.

 

sounds to me like a bad turbo hose. If you can hear a turbo spool you should at least have one working.

 

BMike, you can also use brake cleaner. The motor will sputter when it takes in some of the brake cleaner. That's how PFS does it

 

I'm not sure just how much I'd trust spraying brake cleaner all over my vacuum hoses etc. I'd imagine at least some formulations would be pretty bad for rubber/silicone etc.

 

Beyond the coupler hoses as mentioned above, check the Y-pipe fittings where the Y-pipe joins up with the turbo housing. Because you are experiencing the whine at WOT it is likely to be the junction at the secondary turbo, which is a bitch to see without removing the intake plumbing to the rear turbo.

 

I had a similiar high pitched wine (like the turbine was eating itself up), and ended up finding out that the connection between my tb and elbow was loose. Only made the noise when I made more than 5psi of boost. Kinda sounded like a had a big single. Although I was noticing extra lag and the inability to make full boost sometimes.