BoostFrenzy

I unplugged the stock BPV from the airbox just to sound ricer for a momment and noticed with city driving and low throttle, it will vent under partial throttle (no boost being made anyway)... is that normal? on any other car i can't make the BPV/BOV open unless I drop all the way off

dubulup

It's normal, the stock BOV will vent at a low in-hg reading. David Garfinkle has changed the spring to vent at a higher in-hg reading.

BoostFrenzy

oh ok, learn something new about this thing every day...

rotorbrain

if you get an aftermarket piece itll help, but if you want a stocker. . . contact "garco motorworks". . . i believe he has an extra "modified" bov

you can try doing it yourself, but this thing can be easily ruined if youre not careful. poor davids hands were mangled after he got done.

basically, you scrape the glue out between the top and bottom sections. thats the hard part. then you try a bunch of springs for their pressure rating. what youre looking for iiiiiiiiiis. . . a spring that allows you to stay shut at idle and cruise conditions. how do you find this out? take a look at your boost gauge. record the idle vaccum reading. youll need to find a spring that will keep the bov SHUT until JUST BEYOND that point. id go a little more as well. . . for safety margin. . . well, not safety, just WORTH. if you idle at 15inhg, you dont want it to open at 16inhg. . . too close. the engine will go down to around 20ish inhg when the throttle is let off. just try to keep it in that region. . . BUT not too close. youll get compressor surge if it opens TOO late.

a local put one of these modified bovs on his stock FD and found a bit of increase in performance as well. . . thats what he said anyways. the bov was staying closed longer/sooner through a boost run allowing about 1-2 psi sooner in the rpm range. . . i thought it was interesting.

CantGoStraight

If your talking about below 3 to 4.5k under light throttle then I believe the noise your hearing is the crv venting secondary boost.

mad_7tist

/\ yep.

quicksilver_rx7

My thoughts as well. I have noticed that you can get at a certain RPM and the Charge Control Valve will constantly be open. (Constant swooshing sound). As soon as you pass from vacuum to boost, you can hear the valve close and watch your boost pressure rise (if you have a boost gauge).

Joe

rotorbrain

if he vented the bypass valve then hes hearing the bypass valve leak. it does leak. . . and thats what aftermarket bov's are for.

CantGoStraight

I guess the key word is "if" since we don't know exactly which one he vented (top or bottom hose) then we don't really know. My factory BOV took a min of 12 in/hg to open at all so I would suspect the crv before I'd believe it was the bov.

then hes hearing the bypass valve leak. it does leak. . . and thats what aftermarket bov's are for.

BoostFrenzy

i'm venting the one with the vacuum connection off the UIM, nearest the airbox

quicksilver_rx7

Just get a vacuum pump and test both the CRV & the CCV. That will tell you for sure if either one is bad. It is very rare that the factory units go bad. You may be the rarity, who knows until you test them.

Joe

kraked

Mine vents at partial throttle too, sometimes it makes a queefing sound...