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Old 01-22-2005, 05:02 PM   #1
chillinthemostsp
Scooby Newbie
 
Member#: 61571
Join Date: May 2004
Chapter/Region: TXIC
Location: Dallas, TX
Vehicle:
2005 STi
WR Blue

Default Need some help understanding BOV

OK here is my question. i am kinda new to the whole BOV concept. i have a 2005 STi and i have talked to many people about what are the pro's and con's of a BOV for my car. i have gotten about 50/50 with people saying you can do it or don't do it. i am curious as to what bad things can happen if i put one on, and also what good can come of it. i currently have a Turbo XS RFL on it that one of my friends is letting me use. i am noticing that when i shift that its more jerky. i have heard that it can screw with your engine management and i don't really want to screw up my car. Thanks for the help i appreciate it.
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Old 01-22-2005, 06:01 PM   #2
WRXdriver04
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Member#: 72560
Join Date: Oct 2004
Chapter/Region: SCIC
Location: LA soon to be La Jolla
Vehicle:
04 WRX (stg. II)
java black prl

Default

i dont know for sure but ive been asking around too and i hear that it just doesnt really do anything helpful.. mostly for show.

im sure somewhere down the line with enough mods a bov might help out finally. but for the most part, imo, its mostly a "look at me" mod. i think u could put the money toward something else that will be definate positive for your car.
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Old 01-22-2005, 06:24 PM   #3
Chuck H
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Join Date: Jun 2002
Chapter/Region: NESIC
Location: Chelmsford, MA
Vehicle:
KTR tuned 2003 WRX
VF34 equipped, 270 whp

Default

Have you ever considered using the search feature on here?

That question gets asked at least once a week and generally results in the original poster getting mercilessly abused at the hands of the old timers.

A BOV isn't a good mod for a WRX or STi running stock engine management because it vents air that has already been metered by the MAF sensor out of the intake tract. The ECU, meanwhile, adds fuel assuming that the air you just dumped is still going into the cylinders and you end up running rich for a moment on every upshift. That's where the jerkiness comes from. Your car already has a recirculating valve that performs the same function as the BOV to save the turbo from compressor surge, but it dumps the air back into the intake rather than out to the atmosphere, avoiding that momentary rich condition. Of course, it doesn't make that TF&TF noise that everyone is looking for, but it works just fine for what it was designed to do.
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Old 01-23-2005, 02:14 AM   #4
vnmvx-0
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Join Date: Nov 2003
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03 Snoobie

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Quote:
Originally Posted by Chuck H
Have you ever considered using the search feature on here?

That question gets asked at least once a week and generally results in the original poster getting mercilessly abused at the hands of the old timers.

A BOV isn't a good mod for a WRX or STi running stock engine management because it vents air that has already been metered by the MAF sensor out of the intake tract. The ECU, meanwhile, adds fuel assuming that the air you just dumped is still going into the cylinders and you end up running rich for a moment on every upshift. That's where the jerkiness comes from. Your car already has a recirculating valve that performs the same function as the BOV to save the turbo from compressor surge, but it dumps the air back into the intake rather than out to the atmosphere, avoiding that momentary rich condition. Of course, it doesn't make that TF&TF noise that everyone is looking for, but it works just fine for what it was designed to do.
correction..what you are describing is for MOST BOV's which are usually 100% atmosphere venting, which i agree, will cause your car to run strangely...but if u really want a bov look into a valve like the worxtuning dual stage bov or the aps twin vent some valve that also offers a recirculation back into the intake as well as some venting, so you can get that cool bov sound w/out the driveability problems
(ps i have a worxtuning dual stage bov..love it, car runs fine)
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