yosip1115

Hey guys,

I have been noticing an odd noise on cold startups. My car makes a high pitched whistle noise almost like alternator whining. I originally thought it was a vacuum leak, but ruled that out, although I would like to run another smoke test when it gets warmer. Next I replaced the TB with one I had laying around because the noise is coming from that general area. When I yanked on the main intake tube the noise fluctuated a bit so I rechecked my couplings in that area but no go. Pushing/pulling on the plenum doesn't change the pitch at all. I also went in and checked the plenum gaskets and bolts.

I have a greddy TT kit, with 5k on the turbos. The noise goes away very suddenly once the engine is warm, it will stop instantly when it decides to. It seems like it is only on the first startup of the day with the weather being in the 40's-50's. The few times I drove it this winter the noise was there on every startup when things were really cold. It was also there when driving when it was really cold out one night.

The whining changes pitch with RPM's.

Very broad I know, but I'm wondering if it is the turbo bearings or something related to the kit?

It sounds more like an electronic noise than anything, which is very odd. It's very hard to diagnose something like this remotely, and some may say it would be obvious if they were there in person to check things out. I'm just looking for some more things to check for the heck of it. I don't have any power loss, but it is sort of embarrassing because most people don't know that I yanked the motor, 6 speed swapped it, TT'd it, and did a bunch of other race car stuff that lead to little noises like this.

Thoughts? Thanks

rcdash

iTrader: (18)

If it was the turbo blades hitting the wall, it would be continuous. Intermittent whine sounds like a belt issue. When the belts heat up, they contract and the whine/slip will go away. Tighten those things up! Good luck

dcains

iTrader: (15)

My guess would be maybe a belt or one of the idler pulleys. If you want to know for sure, pull off the belt(s) and see if the noise is still there. Could also be the alternator, PS pump, etc., and with the belts off you can spin the pulleys and see if they're all smooth and quiet.

yosip1115

Thanks guys. I'll focus on the belts/pulleys next time the noise comes back. It has been gone since the weather warmed up