ClubWRX Forum banner

21 - 40 of 11972 Posts

·
Registered
Joined
·
253 Posts
I wasn't planning to do it anymore anyway :). But I would imagine that the BOV wouldn't care where it vents the pressure (either the intake or the air, how can it tell?). The only thing would be that your engine may run richer as the air loss calculated from the MAF went out into the air instead of going back to the intake. I'm still a newbie with turbo cars so I'm just relaying what I've read.
 

·
Registered
Joined
·
397 Posts
You dont want your bov venting to atmosphere - that will cause a loss of power. Take out that stupid resonator and youll be able to hear it better, along with the turbo spooling up.

Joe
 

·
Registered
Joined
·
255 Posts
alright a bov vents pressure to the atmosphere. lots of people use it interchangably with bypass valve which is what our car comes with. bypass valve vents back into the intake.

as for the question as to if it is ok to just take off the hose and vent to atm. does anybody have a solid answer as to why the bypass valve will malfunction if done so. im not saying it will not prematurly malfunction but i would like to now what will cause it because this is an interesting topic to me. cause all your doing is taking a hose off the line which in my thoughts does nothing to cause it to break.:confused:
 

Attachments

·
Registered
Joined
·
6,580 Posts
Here we go. Another long post from clubwrx's resident MechE.

The "bypass valve" used interchangably with BOV (T1 is right, this is not correct) is designed to open and release pressure to a different (lower relative pressure) location in the intake manifold. It is not designed to vent to a zero pressure (atmospheric pressure) location and simply removing the hose will put too much of a pressure difference (Delta P) on the valve actuation unit (which is controlled by a vacuum pulse). This will cause it to fail prematurely, as I previously stated. Add to this the fact that it only opens occassionally because it has a very stiff spring in it and you can see why this will cause problems.

While a lot of people don't believe a BOV is a performance mod, NJSubieTech and I will ardently disagree with them. A high quality BOV (like the APS/Cobb Tuning unit, which is worth the extra $150) will allow the excess high pressure between the turbo compressor and the throttle plate (or butterfly) to be instantaneously released to the atmosphere when the throttle is snapped closed. This release of pressure still occurs with the stock "bypass valve," but much less efficiently.

A good BOV, not one that's just designed to make a neat sound, will protect your turbo from the sudden pressure increase during shifts, and allow it to return to maximum boost faster after a shift. This has been proven by NJSubieTech in races. The car with the BOV pulled evenly with the stock WRX until shifting into second, then the car with the BOV would start to get away with each upshift.

As far as harming the engine in anyway, would a Subaru technician put a BOV on his car if it was going to hurt it? Even Dan (God) has stated that all cars go lean when the throttle is snapped closed, whether it has a BOV or not.

The qualities of a good BOV are:
1) Dual-vent capability so that the BOV can mimic the stock unit during lower rpm upshifts
2) Stock mounting without any kind of adapter plate
3) An adjustment for full atmosphere to full intake vent-back
4) A large piston that moves completely out of the way when the throttle is suddenly released
5) All of the hardware necessary for installation
6) Directions for installation and tuning the unit

Of all of these qualities, the APS valve only lacks directions. It came with no directions what-so-ever. While a person of above average intelligence can figure it out, I firmly believe that everything, and especially car parts, should come with directions. Whether or not you choose to use them should be up to you.

NJSubieTech, feel free to correct me if I am off base at any point in this very long post.

-Jim
 

·
Registered
Joined
·
499 Posts
Stupid BOV install question...

I've got one of those dual-vent GFB BOV's. Using the dual-vent option is nice, but now I want more noise. It's time to seal off the vent on the BOV leading to the intake and go with 100% atmosphere vent.

My question is, what is the best way to seal off the remaining vent to the intake? ...or with what? Is there a part I need?

Thanks

-- Rich
 

·
Registered
Joined
·
212 Posts
i just sent you an e-mail....actually 2.

there are in fact 2 pieces that are supplied with the GFB BOV that allows for 100% vent. A plug and a plate. The plug is most important, the plate less important. You need the plug....

doug
 

·
Registered
Joined
·
330 Posts
how come my bov seems quieter?

ever since i changed to synthetic. my bov seems quieter. and i get that skipping sound more often (it goes pah, pah, pah not pshhh)
 

·
Registered
Joined
·
120 Posts
Turbo XS BOV

Does anybody fid this BOV to really make shifting a chore? It seems that there is a reall fall in RPM so you have to really think to give it some more gas befreo you shift to the next gear otherwise you get lag...


Seems like it makes shifting harder...

Also it makes my muffler all dirty with the dripping unburned gas...
 

·
Registered
Joined
·
110 Posts
Driveability is the exact same reason I sold mine. My car runs much better with the BOV venting back into the intake. The Type H is a great product but the car doesn't need it.

Later,

Dale
 

·
Registered
Joined
·
120 Posts
Yeah I took my BOV off for the winter becasue it just made the car not drive as smooth. Also I did not want to have to be wiping the tail pipe every week to get the excess unbrned goop off of it.
 

·
Registered
Joined
·
5 Posts
Blow Off Valve

Hey i just recently bought an 02 WRX and its my first car so im slowly learning about cars..and i was just wondering...if you can buy a blow off valve for the stock Turbo? Thanx Latez

BlaZiaNWrX
 

·
Registered
Joined
·
268 Posts
Yes. The car already has a bypass valve which can be replaced with an aftermarket valve (either bypass or blowoff type).

The differences are bypass vents back to intake and is generally pretty quiet. Blowoff vents to atmosphere and is generally louder.

BPV keeps stock design. BOV isn't like stock. Word is some BOVs can cause CEL. BPVs will not.

I have the Forge BPV.
 

·
Registered
Joined
·
268 Posts
CEL = check engine light. Just tells you somethings not right.

My understanding is that the BPV vents air back in that the MAF told the ECU is already there. So no problem. BPVs are also claimed to reduce lag when getting back on the throttle after shifts and such due to air being put back before the turbo.

However with a BOV, the air is no longer vented back to the intake and instead out to the open. So it can confuse the ECU. I'm not sure what exactly the code is people are getting. BOVs usually sound better.
 

·
Registered User
Joined
·
4,769 Posts
Si2WRX said:
BPV keeps stock design. BOV isn't like stock. Word is some BOVs can cause CEL. BPVs will not.

I have the Forge BPV.
This is completely incorrect. I know of no BOV on the market that will cause any CE lights unless it was installed improperly. I am using the Blitz BOV and it works flawlessly.
 

·
Registered
Joined
·
5 Posts
Thanx SiR And God...
God you are using it on the stock turbo right?...and does anyone have ne links for where i can parts for my 02 WRX? Such as a blow off valve...sorry...i am a real real big newbie with cars..haha..just happy to have such a great one.. :) thanx..

BlaZiaNWrX
 
21 - 40 of 11972 Posts
About this Discussion
12K Replies
2.3K Participants
RayfieldsWRX
ClubWRX Forum
We invite you to join our Subaru Impreza WRX and STi community to discuss engine mods, builds, detailing, and more.
Full Forum Listing
Top