aquack

I have a ss turbo with a trifecta tune and 3"downpipe. It just started making a a vibrating fart sound(only under boost and when warmed up). Sounds like it is coming from turbo/downpipe. It runs flawlessly when it is cold but starts after about 5-10 minutes of driving. Again, only happens under boost and boost pressure does not seem to be affected much if at all?? I had my local mechanic check for exhaust/downpipe leak and he said it is fine. Is it the turbo? Blow off valve? Anything else?? Thanks in advance.

Wangspeed

iTrader: (2)

My bet is on an exhaust leak or a heat shield is touching a flange.

aquack

OK, I took the car into the garage. They felt the catless down pipe blew out the muffler insulation or something. I checked around and other agreed it was a possibility so I bought a 3 inch stinless cat back system :-) However, the car is still making a groaning muffled sound coming from near the downpipe and maybe turbo area? Any suggestions? Is my turbo going? There is no smoke or oil and it is still boosting--what could it be?? Thanks

Wangspeed

iTrader: (2)

It didn't "blow out the muffler insulation". That's a horrible diagnosis. Jack up the car, put jackstands under it, and go look. You will either see soot from a leak somewhere, or it's touching something. Guarantee it if the downpipe is the only thing you did.

redcomet303

iTrader: (1)

Wow I wouldn't go to that shop anymore

aquack

It ran fine with the new down pipe for moths. ?? I will follow your advice though. Thanks

outtamymind

its not your turbo because mine makes the same noise and i'm n/a. i have midlength header, high flow cat and gmpp performance catback. if that helps narrow things down for ya