I fitted a atmos dump valve to my car(1995 wrx) last week,piston type. It is not making the whooosh noise. Its like a weird fluttering. If i boot it the noise is slightly more normal. There is an adjuster screw i have tried playing with it but its making almost no difference .............ANY IDEAS?????. Its plumbed in on the same lines as the standard recirc. The valve is not new but in very good condition.

 

You say it is in very good condition, but maybe it isn't working correctly? Did you see/hear it before you bought it?

 

Flutter is normally wastegate/turbo chatter
This shouldn't affect the boost noise unless you have a boost leak i.e not plumbed it in right

The BOV only really does anything when you let off the revs so again shouldn't affect boost.

Might just be the noise this valve makes?

 

maybe it drives fine just sounds different!! you can see the piston bouncing up and down when it dumps.

 

What make is it ?

 

not sure got it off a mate, does anyone know what happens if you adjust the spring up or down?

 

by adjusting the spring tighter you will reqiure more boost pressure to lift the piston off its seat when dumping air into the atmosphere. If you slacken the spring off you have the opposite effect - less pressure required to lift the spring off the seat. The tightness of the spring also affects idle.

 

Have you got a pipe from the top of the D/V to inlet?

 

yeah the original vac pipe

 

What BOV is it?

 

dunno what make its a piston type atmos, cleaned it out and it sounds slightly better. Most of the noise is from the air filter,(sounds weird but the flutter is coming from it).Its a pipercross induction kit with the resonator removed.going to get a BOV. Any recommendations?