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.
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.
So did you get it installed or not? I don't just post and try to help out for nothing. Please post how your install turned out, and did you figure out your o-ring problem?
I have Cobb Stage 2 and stock BOV. Holds boost and works just fine. The boost increase is only a little more than 1psi.. though I do occasionally get up to 17psi if the weather is just right. I'm at sea level though, I guess that helps too.
You can't boost higher than that without a bigger turbo anyways. When you get the Cobb Stage 2 installed the cars power will be very smooth....and that's NOT OEM.
I had an aftermarket bov on my stage 2 & 4 and then I went back to my stock and it worked much better. I noticed a huge diff. in response in between shifts. I had the txs rfl. I would keep the stocker until you change the intercooler to a fmic....
My Greddy Type S BOV is on the way. Right now i have my intake silencer out. If my BOV is set to 100% atmospheric, will it be louder with the intake silencer in or out...or no differnce. I know if i set it to recirc. then it will be louder with the intake silencer off. But what about on 100% atmos??.. thanks!
I am a newbie to WRX's and I hear a lot of talk about BOVs.
Does upgrading to an aftermarket BOV do anything for performance or is it just a sound thing? I understand that if you are running higher boost then you should go to an aftermarket BOV but does it do anything on a stock application? Thanks for the help.
I kind of know what BOV is now, and what it does. My rex has
4500 miles on it. Here is my question....is it worth it to buy a BOV
for my car? and will it void the warranty in any way? I know about
dealerships saying it has to be directly related to the cause of a
problem....BUT, should I get one to help my turbo last (and the cool whoosh sound)????...and just
remove it if I get problems and need to go in? Also, where exactly
does the BOV go? Thanks.
I kind of know what BOV is now, and what it does. My rex has
4500 miles on it. Here is my question....is it worth it to buy a BOV
for my car? and will it void the warranty in any way? I know about
dealerships saying it has to be directly related to the cause of a
problem....BUT, should I get one to help my turbo last (and the cool whoosh sound)????...and just
remove it if I get problems and need to go in? Also, where exactly
does the BOV go? Thanks.