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venting your bov to the atmosphere

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dsm92talonboost

10+ Year Contributor
227
0
Dec 15, 2009
sacramento, California
I know their are some post on this but not getting to much info on it. I just curious exactly what is venting your bov?? and why might it cause you to run rich? My bov is not recirulated.. does that mean its vented to the atmosphere? i have a problem with running lean, think that may be a problem? Im just all confused on this venting thing and what it is!
 
Having your blowoff valve non recirculated is venting to atmosphere. Instead of going back into your intake system after the Mass airflow senor it just escapes.

The mass air flow sensor measures the volume of air pulled through it, and uses that to calculate the amount of fuel that is required. If you let air escape you will run rich.
 
yes you are venting to atmosphere it will mess up your fueling as the ecu will make up for the lost air with fuel
 
I know their are some post on this but not getting to much info on it. I just curious exactly what is venting your bov?? and why might it cause you to run rich? My bov is not recirulated.. does that mean its vented to the atmosphere? i have a problem with running lean, think that may be a problem? Im just all confused on this venting thing and what it is!

I understand that I'm not a mod on this website, and that it's not my job or responsibility to point things like this out. I also understand this is a newbie area. But can you honestly say that you have searched on what venting a bov is/does? There are more threads than I can count on one hand as to what this is/problems that will arise/will it give me a cool "whoosh" sound etc. Just making a point. It's recommended to actually search before asking something that has been answered more times than NOT answered. Please don't come on here and just post something random thinking you'll get a quick response, when just typing in "venting bov" and clicking search will probably reap you better responses. Please don't think I'm flaming you or being a douche, I'm just making a point.
 
Our vehicles are equipped with a MAS system. These sensor units read the air that passed thought them by heating up a "hot wire" or similar to a toasters internal heaters. Air then travels over the hot wire. The wire's electrical resistance increases as the wire's temperature increases, which limits electrical current flowing through the circuit. This is how the ecu calculates how much air is entering the system.

Our MAS systems are before the turbo, so the air is metered entering the system. This means that the ECU calculated the air before the turbo, if you are release air after this sensor the ecu can not properly calculate how much air is n the system. It is considered to be un-metered air. That is why boost leak tests are so important, un-calcualted air enter or existing the system can mess up your fuel to air ratio.

If you want to vent, vent properly. Utilize another system of calculating air, whether it be a GM blow through style MAF or Speed density (map sensor and air inlet temp). These two systems calculate air that is in the system rather than before/entering.

I dont think you searched hard enough:

http://www.dsmtuners.com/forums/fre...tions/113858-venting-your-bov-atmosphere.html

http://www.dsmtuners.com/forums/hangout/336295-science-not-venting-atmosphere.html

goodluck


edit: nice link Bud, great minds think alike
 
Last edited by a moderator:
In my experience venting to the atmosphere on a stock MAS might make your car run a little weird at idle and possibly cause your car to die after a high rpm shift, nothing worse than that. Sounds to me like your real problem lies elsewhere, but it won't hurt to recirculate the air properly.
 
thank you for all the help, and yes i should of searched harder but i just wanted some more direct info on exactly what it is which you guys told me.
 
However, that won't solve your running lean problem. How did you determine that you were running lean.
 
I think the big problem is when people run the bov without the recirculating tube on they don't plug the hole in the intake pipe that is after the maf sensor so thats what causes the AFR to act funky. If you plug the hole and don't use the recirculating tube you shouldn't have any issues with it.... I never have anyways. And lets face it I might sound a little childish here but everybody loves turbo cars that have awesome sounding bov's unless you live in California or somewhere else you need to keep it on the hush hush. Again that's just me.
 
I think the big problem is when people run the bov without the recirculating tube on they don't plug the hole in the intake pipe that is after the maf sensor so thats what causes the AFR to act funky.

If they do that, then they deserve to take a bus. :)

My guess is that people are venting 2G with a stock CPV. The only good thing to say about this is that they probably have very clear cylinder wall, washed clean by the extra fuel.
 
Since we on the subjects of BOV's. Is the one that comes free with the PR FMIC acceptable ? I must admit i like the "PSSHHH" sound. Im sure it will make my girl wet hahaha it sure does somethin for me.
 
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