Hey, got a 97model A3 1.8t standard dumpvalve packed in so i bought a dumpvalve off ebay (forge) its an atmospheric twin piston one, ( i know you all reccomend re-circ's but i want abit of noise ) any way, i fit the blanking plug in the air intake.. fit the dumpvalve to the metal boost pipe at the back of the engine and fit the vacum hose. It is not dumping at all ?? it does blow off ever to slightly at real high revs but hardly what can cause this??