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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





 
#4,827 ·
Generally speaking, any moving mechanical device needs maintenance at some point. I've bought 3 used bov's and I cleaned and lubed each one before I put it on. The worx unit is VERY easy to open (couple of hex screws on the top). Once you open it up, wipe everything down and maybe use some compressed air, smear on some lube (worx recommends lithium based lube if I remember correctly), and put it back together. It literally takes 10 minutes to do and it gives a little piece of mind. Good luck!
 
#4,830 ·
That's not what he asked.

I noticed this bov a couple of months ago and asked greddy if they were going to make it in a wrx flange and they said no. So you would have to make your own flange for it. Also, me and some guys on the evo forums were talking about it. One guy installed one on his evo and he has a sound clip. Check this thread out.
http://forums.evolutionm.net/showthread.php?t=112539
Here is a direct link to the video.
http://www.gscdownloads.com/greddyrsbov.wmv RCSA
 
#4,833 ·
the turbosmart unit calls for a light sewing machine oil. (better than 3-in-1 oil.) the piston in a channel style of BOV needs constant cleaning and lube. There is another style that is like a valve with a stem that works longer between cleanings. Some dis-similar metals will make a battery effect with salt (plating). Light sanding with 1000grit will free up any BOV followed by a metal polish, then a light oil.

My BOV adds 75 HP!
 
#4,834 ·
i spoke with TURBOXS about this over the phone when my type H was sticking, or so i thought, but thats another story (attesting to my downsyndrome). he told me that most BOVs do NOT require cleaning to prevent sticking. however, he claims that because of the hood scoop on our cars, he recommends a good cleaning after 15K miles or so. he said he did this to his own car once and never bothered cleaning it again. i followed his advice and cleaned mine about 15K miles ago and haven't cleaned it again (im currently at 33K). hope this helps...
_\m/
 
#4,839 ·
Worx Tuning BOV flange is too big!

I picked up a Hyperflow TMIC this weekend and discovered and interesting fact when I attempted to install the Worx BOV in the parking lot.

The Worx flange is about 1cm wider than the stock BOV flange!

This caused some interesting problems. Luckily, I had an extra TXS type-H sitting at home that has the proper flange size, but I want to use the Worx! It was performing beautifully, eliminating all the problems I've been experiencing with the TXS (compressor surge, etc).

So, moving beyond the informative stage of this thread, I'd like to know if Worx manufactures another flange that would fit. Do I have to grind the thing down until it fits? What's up?
 
#4,842 ·
bov harmful during cold season?

i have an turbo xs rfl and was wondering if i should put it back to stock since i'm in indiana's 0 - 30 degree weather. will the cold be damaging???
 
#4,844 ·
Should I take my BOV off?

Few of my buddies are telling me to take my HKS Bov off and that it is for sure making me lose power... is this true? I love the sound and the epxresions I get from people..lol but I don't want to be losing power.. I currently have a 3" TBE ecutek and this BOv.. should I lose it? also... I don't have the stock one if I do take this off is it ok to just take it off without puting the oroginal one back on?
Thanks
 
#4,845 ·
It won't actually make you lose power just because its one there. If you are not having any problems with driveability, the car ildes fine and you are boost correctly, don't worry about it and leave it on.

The reason I didn't have faith in aftermarket BOV's when I had my WRX was because my GFB would almost make the car die when it was at idle, and the Forge 50/50 would flutter heavily under boost. So I always stuck with the stock BOV. Well, and the fact that I get sick of the PSSSTTTTT after a while.

To tell you the truth, I have a HKS BOV on my SRT-4 right now and I am enjoying the sound. But it will probably come off the car in the next few weeks when I can't stand it anymore.
 
#4,847 ·
biggist problem with bov aftgermarket is that some people crank them down causing the waste gate to fludder. yep that = turbo trying to spin in the wrong direction. if it's on there right i would say no worries.
 
#4,848 ·
hybrid gti 2 said:
biggist problem with bov aftgermarket is that some people crank them down causing the waste gate to fludder. yep that = turbo trying to spin in the wrong direction. if it's on there right i would say no worries.
That's exactly what happens to me.
I have Worx BOV and it came set on the second from the easiest spring level. When i had it on 100% atmo it was almost stalling because the piston in BOV would not close vents fast enough after letting off the gas, and also it had some waste gate flutter. so i adjusted it to the middle spirng setup (stiffer) and the idle was ok but flutter became even worse and valve would not vent enough. Idle was better but i didn't want to kill my turbo. Went to the most easy sprint setup and flutter almost dissapered but idle is even worse. If you drive it on 100% recirc it's fine. So i went back to Worx-factory-spring-setup and now i don't know whether to sell it because there is no point of keeping it if i want to run 100% recirc, or to sell it. ???
 
#4,850 ·
Wouldnt that be something interesting.....you really dont need any kind of bov do yeah? No aftermarket no stocker....toss em all.
 
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