Foxtrot14

Hey everyone. Got a problem with my 1.8t. Under boost I can hear the turbo spool up and around 10-15 psi I get a loud whoosh which sounds an awful lot like a boost leak or loose vaccuum hose except for the fact that I don't lose boost, least not on the gauge, although the car feels sluggish after this point. This problem has started since I put on an ATP downpipe. Any ideas? I can look for certain specifics if you have any clue what this could be? Put on a Forge DV last year after an APR stage 1 tune so I do not think that is the problem. Thanks for any help anyone can offer.

More specifics: 2000 A4 1.8tq, APR stage 1, Forge Splitter Valve(full recirc), Borla cat back exhaust, ATP downpipe.

rdA4WtQ5

Sounds very similar to our now sold stock 2000 1.8t.
There is a hose with a molded 90° bend near the firewall driver's side that will split on the far side from view. It will not leak under vacuum only under boost. Over 100K miles, I would look there first. Good luck!