Apexi Duel Chamber Bov

[JackStar]

Ive just fitted my apexi bov and i cant seem to adjust it, when i do adjust the screw at the top, which must be the spring tension, nothing really changes, same as the red ring that changes the hole size, the sound stays the same, i was hopeing it woud change.

ive also had it apart, and its all ok inside, all moves ok

Can any one help

It just sounds like a quieter blitz bov, which is what ive just taken off

Thanks Jack