To those with Blow Off Valves
11-10-2002, 11:11 PM
#2
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i don't have a BOV, i have a CBV (compressor bypass valve). jsut so you don't get flamed in the future aby any asses, i though i'd point out that a BOV vents to atmosphere, and a CBV is a closed system. other than that they are the same.
as for mine, i run a closed loop system because my car uses a karman vortex MAS, and fucking hates venting. if you run pure map or speed density you can vent to the atmosphere all you want.. i think.. you may not be able to with MAP, i can't remember. anything MAS based will have ot be a closed system to function properly.
hope that explanation helps.. going to sleep for tonight, i can explain further if needed later..
as for mine, i run a closed loop system because my car uses a karman vortex MAS, and fucking hates venting. if you run pure map or speed density you can vent to the atmosphere all you want.. i think.. you may not be able to with MAP, i can't remember. anything MAS based will have ot be a closed system to function properly.
hope that explanation helps.. going to sleep for tonight, i can explain further if needed later..
11-11-2002, 07:28 AM
#4
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2nd gen RX7's have MAS........they can be vented to the atmosphere w/o problems..... I have a 3rd gen w/ MAP......i definately vent out to the atmospere
11-11-2002, 08:03 AM
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you can vent to atmosphere w/ MAF only if the BOV doesnt leak at idle....i know for a fact that the HKS super sequential BOV can be used on a MAF equipped car with no problems...there are a few others...you can also vent to atmosphere with a MAP equipped vehicle no problem
11-11-2002, 10:00 AM
#6
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since i have BOTH a Maf, and Map sensor....venting to the atmosphere becomes a problem, depending on how my ecu wants to feel at that certain moment. my efi is tricky...so people among the wrx communty tend to either keep it reciruculated or go 50/50. to those wrx's who vent to the atmos. they either have idle problems....or run really really rich between shifts...which throws their fuel curves outa whack. then again...there are alot of wrx's out there that dont have a single problem with venting to the atmos. either they have their ecu specfically tuned for it, or they just got lucky and their efi has adapted accordingly.
my stock bov (compres bypass vavle) can handle up to 18 psi without leaking anyways...so i think ill keep mine for a while.
my stock bov (compres bypass vavle) can handle up to 18 psi without leaking anyways...so i think ill keep mine for a while.
Last edited by JKim; 11-11-2002 at 10:03 AM.
11-11-2002, 10:06 AM
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The problem with venting a BOV on a non MAP sensored car, is the fact that you run rich between shifts. This is caused by the ECU not recognizing that air has escaped (the air is metered BEFORE the BOV) and therefore still adds the fuel for the air that has been released, causing a slightly rich condition between shifts. If you just want a nice ricey pshhh sound and dont care about performance, then if your BOV won't leak when its vented go for it. If not then I would highly suggest recirculating it, as that is the true performance oriented way of doing it on a non MAP sensored car. For you Map sensor guys, blow off your load all you want, just not in my direction .
.
11-11-2002, 04:36 PM
#9
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Originally posted by Mugent3/t4e
My BOV vents to the atmoshpere because its makes a louder sound and people can hear it better when I rev on them....
My BOV vents to the atmoshpere because its makes a louder sound and people can hear it better when I rev on them....
11-11-2002, 06:39 PM
#10
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i want to add a couple things....
i have a open bov and mass air flow sensor car. with out my s-afc, it tends to want to stall when i go to neutral. with my s-afc, its not really a problem. there is a feature that leans the car out when you let off the gas. my car runs fine this way and has for the past couple years.
another way to deal with this problem is to plumb your maf after the turbo and have it as a blow thru setup. afaik, most hot wire maf car will not have a problem doing this. if you have it 12" before the throttle body, and your bov is 24" before the throttles body, you have no unmetered air entering the engine. this is the first thing i would try. maybe a little difficult for some as fuc-n apc doesn't make a intake set up that does this for you. i hope that helped somebody out a little.
shaun
i swear it will hold 30psi for 3 seconds....
i have a open bov and mass air flow sensor car. with out my s-afc, it tends to want to stall when i go to neutral. with my s-afc, its not really a problem. there is a feature that leans the car out when you let off the gas. my car runs fine this way and has for the past couple years.
another way to deal with this problem is to plumb your maf after the turbo and have it as a blow thru setup. afaik, most hot wire maf car will not have a problem doing this. if you have it 12" before the throttle body, and your bov is 24" before the throttles body, you have no unmetered air entering the engine. this is the first thing i would try. maybe a little difficult for some as fuc-n apc doesn't make a intake set up that does this for you. i hope that helped somebody out a little.
shaun
i swear it will hold 30psi for 3 seconds....