Just thought I'd menition I bought a 50mm tial knock off BOV from Scott and had the same problem. Mine wouldn't open at all. Well, after a week or so, it just started working. I still get a spec of surge, or w/e it's called, before it opens though. Like I'm driving normal, shift at 3k, and I hear it flutter for a sec., then the I hear the BOV open. Anyway, I think it was just 'stuck' at first as it seems to be working fine now. I'm'a have to update my review of his stuff in his sub-forum. Everything else I bought from him has worked perfect.