hey guys/gals.

I have a 225 quattro coupe. APR downpipe/APR 3" turbo-back exhaust.

At 2700rpm all the way up to 3300 rpm I hear this rather loud grinding/vibrating noise, like something (im thinking exhaust) is rubbing on something very fast and voilently.

The odd thing is, when its wet out and I am driving in the rain, it gets louder. WAY louder, like 3 times as loud. It sounds like its coming from the middle-rear of the cars underside, but I could be wrong.

any idea what this could be? the exhaust is not touching anywhere.

 

try pulling the halidex fuse and see if it makes a difference. There is also a way to physically disconnect it. Not sure how though.

 

termites...


do you hear it when parked or just driving? Find someone to work the gas and try to track it down with your ear. Could just be a busted exhaust hanger or something.

 

standing still or driving both produce the sound.

anyone know which fuse is for the haldex?

 

ABS fuse might work... Haldex doesn't work without signal from the ABS

 

ok its fuse #31.

the part that has me baffled is that it happens louder and more aggressive when wet...wtf?!

 

I think my prop shaft was rubbing on a piece of shielding or something, made some nasty noises, usually after a hard right, and would taper off as something shifted/vibrated away from the shaft again. Dunno about the rain thing though.
I never really found out what it was, it just stopped one day. Assume it was something that bounced up under there, and it eventually fell out.