2011 A4 turbo spooling noise
 

Hey all,

I've had my 2011 A4 2.0 TFSI for about 35k miles now, and it's had an odd turbo spooling noise ever since I got it new. Two dealerships have told me it's "normal" but I'm not totally convinced. So here's what happens:

When accelerating from a dead stop, after about a 1-2 seconds, at around 2500 rpm the turbo starts to spool. The spooling is louder than other B8 A4's I've ridden in, but otherwise normal. After 1-2 seconds of normal spooling it begins oscillating in pitch slightly and rapidly, like a bird chirping. The noise is lightly audible in the cab with the windows up. It seems to be only when the throttle is open in a certain range, if I floor it all spooling noise goes away entirely, and if I accelerate gradually there is no spooling noise at all.

Has anyone else experienced this? It doesn't sound as serious as compressor surge or wastegate flutter. Even if it's "normal", what can I pursue to fix this? If nothing else, it's annoying and embarrassing and I'd like to fix it, especially with my 328 driving roommate giving me crap everything we take my car.

Thanks for any advice!