Ok, so recently (or at least I can't remember this happening before recently) I have been hearing an interesting sound on my TT with a stock engine. After I exceed 2000 rpms, or when the turbo starts to kick in (whichever is first) and than I let off the gas I hear a "woosh" sound or what seems like the discharge of air from somewhere in the engine. Is this normal or is there a problem with my engine or turbo? If there is, would the dealer be able to pick up on the problem?

 

Sounds like you might have a boost/vac leak in one of your lines. Do a visual inspection of your hoses and look for cracks and broken hoses. Putting the system under pressure should help.

 

Edit.

 

thanks that is what I have been lead to believe, three questions though. Is there a reason why one of my hoses would be leaking or cracked? Also how do I put the system under pressure? Lastly, how much does something like this cost to fix?

-P.S- I saw your rims on your tt and I have to say those are the best looking rims on a TT i have ever seen

 

Thanks for the props on the wheels. A lot of times, the rubber in the lines will dry rot or desinigrate due to heat in the engine compartment. And the fact that lite oil residue gets blown through those lines makes it even worse. The hoses themselves aren't that expensive if you replace them with scrap hose or stuff not from the dealer. Going to the dealer to replace those hoses is really expensive. As for a pressure test, I'm not sure where to find a DIY, but starting an account and then asking that question on audifreaks.com would be a good start towards finding a good link/source.

Are you losing power when you hear this, or is it at the peak of your power band?

 

There is minimal to no power loss, and if there is any it's hardly recognizable. I was told to check around the diverter valve and I'm going to do that soon.

 

Wait, you said it happens when you take your foot off the gas, right?
That's just your diverter valve discharging the excess air in the turbo piping to the intake.
Should be perfectly normal, unless it's a loud woosh or it sounds like a duck, then your DV might have come loose or died. Do you have the stock airbox or an aftermarket intake?

 

I had to service the car anyways so I took it in, and they found some interesting things that seemed to fix the problem. Apparently there were a family of MICE nesting in some filter in the engine...