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Discussion Starter #1
the title explains it, but i've read around about the BOV. I was wondering when a BOV is really needed? I've read that it's needed for higher levels of boost, but still uncertain about the details.

Also, the WRX is going to be my first FI car and really wanted to here the turbo spool and BOV give that WHOOOSH sound. Would an intake give of the effect?
 

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You are correct about the application of an aftermarket BOV. The spring in the stock one will only withstand a certain amount of pressure before it starts opening prematurely. This is where the aftermarket comes in with BOV's that have stronger springs and are adjustable to you boost level. That being said I have no idea how high of boost you can run on the stock piece.

The spooling sound and whoosh will be much more pronounced with an open element intake. The only way to make the BOV really loud is to buy one that vents to atmosphere or a hybrid that partially recirculates. I would avoid the atmosphere dump on these cars as the computer is expecting to see the vented air back in the intake and adjusts fuel accordingly.

Good luck
 

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There is no performance need for a new BOV on your WRX. The stock unit works beautifully and can hold upwards of 20psi from the tests I have seen. If you are going to replace it, I'd replace it with another recirc. valve instead of an atmospheric vented one. With the atmospheric one your venting air that has been accounted for in the tune.
 

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Discussion Starter #4
Oh i'm not interested in an aftermarket BOV (my friend with an 04 STI told me it gets annoying) But does the BOV really give no performance gains?
 

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I just installed the TurboXs Hybrid on my car. It has a nice whooosh sound but it is not to loud. I would recomened it and it takes about 5 minutes to install. Your car will run alittle richer but that sound not be a problem. Must people will tell you not to get one because they say your money is better spent else where, but if you like the sound, go for it. This is were i got mine. $189 and free shipping.



http://www.street-power.com/turbo-xs-subaru-2008--wrx-hybrid-valve--ws08-hyb--.html
 

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Yes the BOV is necessary. When you go from a throttle open to a throttle closed position that compressed air needs to be released so it doesn't stall the compressor of the turbo. I am sure there are other big long explainations but that would be the gist of it.

Seth
 

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Yes the BOV is necessary. When you go from a throttle open to a throttle closed position that compressed air needs to be released so it doesn't stall the compressor of the turbo. I am sure there are other big long explainations but that would be the gist of it.

Seth
Nah, there really isn't a better explanation. You did it perfectly. It vents the excess boost pressure during shifts or other rapid engine speed changes. Similar to how the wastegate vents exhaust gas on the other side of the turbocharger.
 

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if all you want is to hear the BOV, i would recommend a cold air intake.
you will also hear your turbo spooling, it's music to my ears :)

if you plan on swapping the turbo or getting a tune that's more aggressive than stage 2, get an aftermarket BOV. Performance wise, the stock one is garbage.

my BOV was a stock boost leak and i happend to have a Greddy BOV collecting dust. So i swapped out the stock one.
 

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If I were only interested in a sound upgrade, I'd get a catback before a BOV. That way your car actually runs better, not worse, and sounds waaaaaaay better IMO.
 

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If I were only interested in a sound upgrade, I'd get a catback before a BOV. That way your car actually runs better, not worse, and sounds waaaaaaay better IMO.
Same, no need for a CAI or aftermarket BOV, the BOV doesn't add anything and the CAI can hurt performance if not designed properly (90% of the ones out there).
 

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you can always upgrade to the STI (recirc) one as its got a stronger spring ;) rather than going for a aftermarket bov
 
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