My guess is that the spring inside your valve isn't stong enough to hold the boost you're making. Is it adjustable? If it is, adjust it.geo9000cseturbo said:well i fitted the bailey atmospheric dump valve as above with mixed results. when i rev quite high in neutral gear it makes the nice wooshing sound but when driving on the road the valve is opening when the revs pick up and stays open for a long time..... until i back off the revs it seems. i,m no expert but isn,t this kind of back to front i thought the valve was mean,t to dump pressure only when the gears changed or the revs backed off. is the little pipe attached to the dump valve supposed to be sucking all the time mine is although it isn,t that strong on idling. i,m getting confused my head hurts can one of you saabaholics tell me what,s wrong if anything.
thanx in anticipation