GFB Mach 2 TMS Blow Off Dump Valve Kit for Audi TT S3 A3 A4 1.8T 20v 95-05
Put simply, it can hold more boost than any turbo could produce. Go Fast Bits Mach 2 TMS Blow Off Valve/Dump Valve Kit for VAG VW Audi SEAT TT / S3 / A3 / A4 / Leon Cupra / Golf GTI 1.8 Turbo 20v Engines.