So I just bought a 2001 tt 225 coupe. I installed Revo software (and turned up the boost) and after having it on for about 1 week, a weird noise suddenly started coming from the front left part of the car when the car is in high boost (mostly low rpm, full throttle, in 3, 4, 5, 6 gear). It sounds like something is leaking, a deeper blowing sound sync'd with the turbo spool. The dealership replaced the diverter valve and checked the vacuum lines (or claimed to have) and can't find anything wrong.

Does anyone know what this could be?

Any help would be greatly appreciated. Thanks

 

Can you have someone rev the engine while you open the hood and listen? Do you have a Vag-Com to log boost pressure?

 

A friend of mine does, but he lives far away. The dealership insists that the sounds is normal (although other similiar tt's don't make the same noise) and says it is due to the Diverter valve. I'm so confused...

 

The diverter might be bad too.

 

did u try an aftermarket DV?

 

yes i just installed the Forge DV, but the car still isn't performing as well as it did before the noise, and it is still there...no one can figure out what is wrong, lol...

 

Sound like you might have a IC hose leaking some boost off. I had a friend witha GST Eclipse and he would blow hoses all the time. Just a Thought?

 

Sounds to me like a boost vacume leak check all your hoses make sure their tight and have no holes or tears.

 

The dealership ran all of the vacuum tests twice and had 4 different mechanics try to figure the damn thing out...they even said that it wasn't normal but couldn't find the leak. I will definately re-check all the things you have mentioned. thanks.