Guest bastaad525 Posted August 1, 2003 Share Posted August 1, 2003 something just occured to me. I installed a 1G DSM BOV on my J pipe, and was getting ready to attach some vacuum line from it to the intake manifold... but then I thought... wait a second isn't there vacuum present in the intake manifold more often then not? My boost gauge barely ever gets above 0, it's always showing negative/vacuum. So if there's always vacuum present, and I connect that to the BOV, wouldn't it just hold the BOV open all the time?? I was under the impression that it's only supposed to open when I suddenly close the throttle? Funny thing is, I got on a it a little today w/o connecting the BOV, and I swear I heard it sneeze a couple times when I shifted... so do I need to hook this thing to the intake manifold or what? Quote Link to comment Share on other sites More sharing options...
Drax240z Posted August 1, 2003 Share Posted August 1, 2003 Yes you need to hook it up to the intake. When the pressure is greater at the BOV opening than it is in your intake, (ie: your throttle plate is just closed) then it will open. It will still make noises if you are boosting and leave the vacuum line off, as the pressure in the pipe is greater than the atmospheric pressure... It won't work very well without a vacuum signal though. Also, since you are using an AFM, you have to plumb the air that the BOV vents off back into the intake system at some point or you'll have some issues with running rich. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted August 1, 2003 Share Posted August 1, 2003 Drax is right, the BOV operates on a pressure (vacuum) differential between the plenum and the other side of the throttle. I've heard of some valves that are too sensitive, and the vacuum of idle is enough relative to the atmospheric pressure of the intake to cause them to be open at idle, causing problems (big ones if it's not plumbed into the intake). My DSM BOV is closed at idle, and only vents on a throttle lift, where the cracking pressure is higher than idle vacuum alone. Hope that made some sense. Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted August 2, 2003 Share Posted August 2, 2003 A little well I didn't get a chance to hit the auto parts store today to get a vacuum tee and some hose, but I will say the BOV seems to be working w/o it. If I give it enough throttle to bring on boost and then suddenly let off to shift or whatever I get that cool ricer sneeze sound and I can't say I notice any compressor surge or turbo lag... as a matter of fact this turbo does not seem to lag at all... if I floor it it almost instantly raises up to 7psi, even between shifts. Too bad the engine itself bogs so bad.... feels like it wants to die if I go from closed to WOT. I will still hook the BOV up to the intake manifold when I get a chance. Quote Link to comment Share on other sites More sharing options...
fl327 Posted August 2, 2003 Share Posted August 2, 2003 I run an HKS ssqv bov on my ride, and I love it, it has two valves in it, a small and a big one, on light shifts it makes a girly whistle noise, and on wot shifts it makes this gnarly WHOOOOOOOOOOOOOOOOOOSH. It does not open at idle at all, and uses a pull type valve mechanism, which makes sure it doesnt vent at idle, and it opens and shuts the valve so fast the ecu bearly has time to blink. Its nice, and I highly recommend this BOV. I ran recirculated for a while, and notice no performance difference with the recirculating type vs. open vent. In about a month, I plan to add one final noise to my car and some very nice go fast: The infamous unmuffled open external wastegate dump Quote Link to comment Share on other sites More sharing options...
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