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"The BIG BOV thread" (Where all bov question threads get merged)

2M views 12K replies 2K participants last post by  WRX-maniac 
#1 · (Edited by Moderator)
This is the big BOV thread. If you didn't find this thread, you didn't search.

This thread is where all BOV question threads get merged into.

The quote below in this first post is from our BOV info sticky and contains links to some very explanatory BOV information. Please take the time to explore the links before you ask repeated questions.

Thanks!


A stock WRX/STi comes with a BPV (Bypass valve) which is a vacuum-actuated valve designed to release pressure in the intake system when the throttle is lifted or closed. This air pressure is re-circulated back into the non-pressurized end of the intake before the turbo.

An after market blowoff valve (VTA) does basically the same thing BUT unlike the stock unit it releases air to the atmosphere (giving you the loud sound). Some people see an after market BOV on a stock WRX as being in poor taste (probably due to the fact that it is basically a noise maker that really as no other benefit), while others simply find the sound very attractive.

Proponent opinions notwithstanding, there is a small mechanical downside to having an after market BOV (VTA) on a stock WRX. The problem comes when releasing air to the atmosphere that has already been metered by the mass airflow sensor. When the BOV releases (blows off), the ECU will be injecting the wrong amount of fuel into the cylinders. The engine temporarily runs too rich (meaning too much fuel is injected into the cylinders). This temporary rich condition isn’t typically THAT harmful, but it may cause bucking or hesitation on lift-throttle as well as some other concerns outlined in the links below.


Links for BOV info:

Sinister's BOV FAQ

Wikipedia

Unabomber on Nasioc

Davenow on Nasioc





 
#5,028 ·
boosted scoob said:
If you put a BOV on, then intall the intake it will still run lean maybe. If you put a duck call on your BOV, it will even it out.

:rotfl:

I've' often said we should do something like that...you can get all kinds of air-driven noisemakers and change them depending on your mood...maybe one of those birthday party streamers, duck call, ram's horn, sky's the limit.
 
#5,030 ·
dude i was just asking a question, i dont need you to give me a link to some retarded speaker thing. i think you should sticky something like this, the question seems to come up a lot. but it seems like you like answering questions that people have, as you have done with me. your never know unless you ask a question, be nice.
 
#5,032 ·
i think in the less than a month i've been a member i have seen maybe 9 or 10 BOV threads i think there should be one well written BOV thread with links to different bovs and stuff like that if i have a little more knowledge on the subject i would write one or if People want to PM me different information on BOV's Pro's and Con's i will write one up to be sticked.
 
#5,035 ·
i just thought of this you know what would be funny for all the people who asks which bov is god for stock, have them buy what they think is a bov you get the box you get all excited and then this like hand or something comes out and smacks you hard on the forehead and says dumbass or something....lol that would be funny.....I'm so glad i'm easily amused.... :rotfl:
 
#5,039 ·
Question: HKS BOV problem..

When I first installed it, the sound was really loud and I loved it. But then after driving about 5 hours,, the sound decreased and now, I can bearly hear the sound. I don;t think the BOV part itself has a problem,, then can it be a installation isuue?? or any ideas? :sadwave:
 
#5,040 ·
silver04 said:
When I first installed it, the sound was really loud and I loved it. But then after driving about 5 hours,, the sound decreased and now, I can bearly hear the sound. I don;t think the BOV part itself has a problem,, then can it be a installation isuue?? or any ideas? :sadwave:
hmmmm, did the butt plug fall out of the recirculating hose? did you tighten the two bolts properly, did you put the hose vaccum line back on, is it still on? did you use the little hose adapter? I Have one and it got louder
 
#5,042 ·
BOV ruin warranty??????

im getting a turboxs type h rfl BOV. i m just wondering if this will ruin the warranty if i bring the car in with it on. im getting it regardless if it does, but just want to know if im gonna have to take it off if i have a problem with my rex. thanx for any help
 
#5,044 ·
Trainrex said:
Most dealers seem to frown upon them. I'm not sure I understand the allure of something that sounds like crap, negatively affects performance, possibly affects the warranty, and costs alot. :confused:

man it makes such a cool noise, when I pull into my highschool parking lot and blow off 47 times pulling into a spot, everyone knows my car is turbo! They all come out and go "make it woosh make it woosh" when i'm starting my car.

SO I give it a few revv's, woooooooooshpppstttt and pull out of the parking lot at school.

Then I get wacked by an accord v6 and wish I would have spent my money on a downpipe instead.
 
#5,050 ·
BOV...not blowing off???

My GFB Hybrid BOV i've had on my car for a while is acting up or is it sopmething else. Sometimes it works fine but sometimes it doesn't blow off and the car bogs for a split second. Anybody know what i'm experiencing? I'm boggled.!!
 
#5,051 ·
after doin a search it's probably compressor surge. Is my BOV sticking? it's weird. I can rev my engine up at idle and it will blow off just fine, i drive it for a little bit and it starts to "stick". Any remedies?
 
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