Did some spirited runs the other night back to back, afterwards before parking the car, I drove it around for about 5 minutes without hitting any boost to let the car properly cool down. When parking the car I popped the hood to show someone around the engine bay and noticed the turbo had a slight red glow to the hotside (normal I would imagine after driving it hard). I let the car idle for another 5-10 minutes with the hood up to let the car properly cool down.

The following day and ever since, I hear a strange noise whenever the turbo spools which gets progressively louder with higher spool. The noise sounds almost like a whine/grind noise. Car still boosts appropriately.

I am curious if I should stay out of boost and find an upgrade/replacement to avoid any catastrophic failure which would rack up a higher bill for me. I am going to pull off the inlet hose and inspect the impeller blade for any damage here shortly and I'll post what I find.

Car has 58,--- miles and is running around 355 HP at 27ish PSI on Stock Turbo.

Car runs great and silently in all gears up to 7k RPM. Noise is only present when turbo spools.

 

Compressor side of turbo looks fine, turbo shaft has minimal play and fins have no signs of damage or contact with turbo housing... beginning to think the bearings may be going out? I guess I'll check the hotside when I get a chance as well. Anyone else have this issue prior to their turbo dying?

 

If the shaft doesn't move I wouldn't bother checking the exhaust side. Unless something went flying through the motor / out of the exhaust side it's probably fine. You won't be able to hear bearing failure unless the shaft play is hitting the housing.

Is the noise RPM or boost dependent? Louder with more boost or louder with higher RPM?

 

Noise is not RPM dependent, no noise through any gear at any RPM. As soon as boost kicks in noise is progressively louder as turbo spool increases. As of yesterday I started hearing what sounds like an exhaust leak, so I am thinking that there is a possibility that the hotside housing has a crack or leak, I am going to dig a little deeper early next week.

Thank you for the reply BTW

 

My guess is you have a decent sized exhaust leak and you are hearing the waste gate open (could also be a crack). Does the noise present itself at low levels of boost (i.e. 5-10 lbs of positive manifold pressure), or do you only hear it at higher levels (i.e. 15-20)?

 

This appears to be the issue. After further inspection found that one of the bolts from the turbo to manifold had completely backed out and is now gone. Another one had come loose. I am also missing two nuts on the exhaust-head.

***I would recommend that anyone with an aftermarket manifold either look into an aftermarket solution for bolts coming loose or periodically check all bolts on the turbo and manifold. All of my bolts were torqued to spec when the manifold was installed and re-checked a week thereafter.

I have new bolts on order and will report back with the results.

 

Loctite. lol