So I just can't wrap my head around the idea of tuning a BOV. From what I have read it is based of your engines idle vacuum. So I am -20hg and lower. Tial 50 BOV says Un-painted. Everyone with the ON3 kits or so says gearheadbuilt swap them out with yellow. Sounds different but more importantly car pulls harder. If vacuum is equal on both sides and there is a spring closing the bov then what is the issue? Then boost added to spring still closed. Opens when the spring side sees that vacuum vs the charge pipe still at boost? But yellow is a 11psi rate spring. Sound too large.
Anyone with knowledge please educate me. Thanks

 

11psi is 22hg of vac, You will actual have more vac on decel after you let off the throttle and boost pressure will easily open the BOV. It's really not very critical. As long as you don't get much if any compressor surge, the spring you are running is fine. A BOV has no affect on how much power you make or how hard you motor pulls. All it does is release pressure in front of a closed throttle butterfly.

 

I was guessing the light spring and the vacuum or opening with charge pipe having some pressure and with it opening and closing a few times It is wasting time/air. Oh well I ordered it and will see what happens.

 

Knowledge from Tial
TiAL Sport - Blow Off Valve (BOV) Tech

 

but but but compressor surge sounds so sweet!!! i put in a stiffer spring to allow the surge for messing around and making noises, when i was WOT and max boost then let off the BOV opened.