It's b/c your stock BOV is a plastic POS. I recently chnaged from a Greddy Type S to a HKS SSQV and in the interim time I had to put my buddy's stock valve in my car...my performance went down (dropped about 3psi of boost), backflow made my turbos "honk", and my shitfs were twice as long for the turbos to spool.
Buy an aftermarket one...or at least a old 1st Gen DSM BOV....it'll be well worth it.
Look in my sig, my car IS a 1G, my BOV is not plastic, its metal. and the problem you are adressing is a leaky bov, that is not the case here. in this case the bov sticks open all of the time, causing almost all of the boost pressure to be lost.
Be sure the vac line going to the BOV has <b>nothing</b> else on it - anything less than full boost pressure on this line will cause the BOV to leak. If you're T-ing off of it to use for a bleeder valve for example, it's causing the BOV to leak. The BOV is held closed by a combination of the spring and boost. The spring alone isn't enough to hold it closed.
thanks guys. if i cant fix it with a new vacuum hose to the intake manifold i'll just buy a new BOV. i went under the hood and saw how screwed up the line was. it's probably permanantly wrecked from all this twists and turns, not to mention all the boiling hot coolant spilling on it twice in two months.
The idea is to put more tension on the spring that (along with equal boost pressure on both sides) holds the BOV closed. I've never used a vice; I just whack the top "hat" portion of the BOV until it is concave. If you take it too far, it can't open and you're in need of a new one.
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