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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





 
#1,377 ·
where to buy a RXS RFL bov????

i ordered a HKS bov, but is it loud at all? i've heard some say it is, and some say it ain't. But is the TXS rfl alot louder? and if so, where can i buy it at??
 
#1,379 ·
the soundclip won't work for me, but does it make a noise about all the time, and not just between gears? i heard a clip of one supposdly, and it sounded like that. would it be better than the HKS? of so, i will send it back, and where can i buy the TXS RFL from??? thanks
 
#1,384 ·
does the TXS RFL bov leak boost?

i just ordered it caouse i like the sound better than the hks, but some people say that the RFL leaks boost, is that true? or is it very relaiable? thanks
 
#1,385 ·
I have the turbo XS type H BOV, and it doesn't leak.
It says in the manual that it might leak at idle, and they supply you with some pack washers to put inside the BOV to prevent it from leaking at idle. (if this is what you meant by leaking)
Mine was fine when I got it, didn't need to do anything to it,


SPIDEYWrX
 
#1,386 ·
uhoh.. cut BOV hose - help please!

Alright, so I screwed up last night. I installed a Blitz DTT and everything went smoothly until I got to the boost gauge piece. I mounted it behind the glove box and ran the vacuum tube through the same grommet as the AC drain hose on the passenger size, and the install looks very clean ...

Unfortunately, I didn't read here on the problems with the T connector that came with the DTT. I cut the hose coming out of the BOV, and when I realized my error, tried to jury rig it by wrapping the connector with electrical tape and attaching the hose with zip ties - which worked for about half of the commute to work this morning.

I popped the hood when I got to the office and the tubes had come apart.

I have about 50 miles to drive this afternoon before I'm near a pepboys (where I can buy the CORRECT T-connector), and my question is this : What kind of risks am I running with a possibly cut BOV hose? If I stay off boost, am I in danger of breaking my car?

That'll teach me to install something without reading ALL the posts ...

Thanks
 
#1,387 · (Edited)
Damn, boy, don't you know to keep a roll of duct tape in your car? You could do a quick splice of the original line back together and it would actually hold for awhile if you had some.

But if you can keep out of boost you should be fine, it's just very hard to keep completely out of boost on this engine. It would help to avoid suddenly taking your foot off the gas - rapid throttle closing is the worst for compressor surge. Slow, gradual throttle reductions are easier on the turbo.

Remember, there are cars out there that don't run BOVs at all. You're not going to KILL your turbo, but it won't be GOOD for it either.
 
#1,389 ·
I know, I should have duct tape. I really thought it was going to be fine - I built the connector up pretty well, but it just didn't hold. My biggest fear was having to drive 50 miles before I can fix it for real - I plan on buying replacement hosing and a PROPERLY SIZED T tonight.

What kind of teflon tape are you using? I have standard vinyl electrical tape that is almost as good as useless...
 
#1,390 ·
outlandr23 said:

What kind of teflon tape are you using? I have standard vinyl electrical tape that is almost as good as useless...
I dunno, I can't imagine any way to make an undersized tee work with teflon tape. Electrical tape should be better, but still that stuff gets slippery when it's pulled in shear. Only way I've ever managed to get undersized fittings to work in a pinch is to use a hot glue gun to build up some extra material on the fitting and then slip it in when it's nearly set.
 
#1,391 ·
The teflon tape that you use is the same that you would use on pipe threads. It conforms to the T-fitting. I just wrapped it around the T until it was a little larger than the opening in the hose. Then just squeeze it on and zip tie it. The teflon tape will seal the T to the hose as that's what it's meant to do. I've never had a boost leak and never had any leaking hoses. I've got over 20k miles on the car and run a Vishnu Stage 1 with Ecutek that routinely boosts up to 17psi.

Calvin
 
#1,393 ·
Where did you order it from and how much?

When you got it, you should have gotten the one with the WRX kit, and you should've paid around $225. If these things don't add up to what you got, then you probably got it as a universal BOV. If that's the case, then all you have to do is buy the WRX kit for this BOV. Let me know what happens :)
 
#1,397 · (Edited)
#1,399 ·
it's not free
labor is expensive here in the US

just joking
good luck w/ the bov, i will get mine on tuesday
 
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