Sorry guys if theres already a thread on this. But just curious on how to properly set the spring or " nut " on the BOV, worried it would be too loose or too tight, what is the correct way to adjust that? thanks guys

 

I'm glad you started this thread. My 04 has an Inline Pro setup/BOV and the BOV remains open under all conditions but full throttle/boost. It's annoying. I stretched the spring, tightened the cap all the way down, and made sure it was clean and functional. It still dumps all pressure needlessly IMHO. The result is that upon normal shifting, the turbo takes 1.5 seconds to build to full boost again. Ugh.

I know things are different today, with such setups as 550HP 2.0L street engines, but in years past, (even on 700HP 1.7L road race engines) it was common to run without a BOV. And, if we installed one, it was quite small. The goal was simply to bleed off excess pressure above max boost on throttle lift. In other words, to keep the pressure in the intake system from exceeding some number and creating a compressor stall. The theory was to keep intake pressure near boost levels at all times, and not to bleed all of it off, ever.

The most successful 1.8L road race setup I built used a tiny RX7 turbo BOV. With an outlet about the size of a heater hose! 33 pounds boost. The BOV would just barely prevent compressor stall and the throttle response was stellar. No turbo lag what so ever.

I guess I'll simply have to try different springs until I get one I like. This much is clear, if I remove the vacuum line on my BOV, it remains closed and the part throttle response is significantly improved. (of course, it blows open under boost, as there is no line pressure to assist in holding it closed)