Hi Everyone,

I recently bottomed out pretty badly on my G37 Coupe and now when I accelerate to 3000 rpm, it makes this high pitch grinding/whirring sound. Once I pass 3000 rpm, it goes away. Also, it only shows up about 70% of the time based on how hard I accelerate. If I idle it or rev it in park, it doesn't happen. I had a muffler shop look at it under the lift and they said there are no cracks or damage on the exhaust. Another shop said that when I bottomed out, the exhaust may have hit/moved the drivetrain and that's what is causing the sound. Two different shops said its a muffler issue and that its purely sound with no effect on performance/drivabilty. The sound is a bit annoying IMO and I would like to just get it fixed. Anyone have any idea what it might be? Thanks!

 

Did you possibly bend your mid brace? Your exhaust could be touching it

 

Did you put it on the lift and see the how much clearance you have left? What exhaust you running?

 

Check the heat shield around the rear joint on the driveshaft. It may be pushed up against the joint, which is why you're only hearing it while the car is moving. It's probably not your exhaust if it's making the noise you described.