"The BIG BOV thread" (Where all bov question threads get merged) - Page 664
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This is a discussion on "The BIG BOV thread" (Where all bov question threads get merged) within the Engine Modifications forums, part of the Tech & Modifying & General Repairs category; Originally Posted by Micah Uhm.... no By doing this, you're correcting the problem when it's less severe, and allowing the ...

  1. #9946
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    Quote Originally Posted by Micah View Post
    Uhm.... no

    By doing this, you're correcting the problem when it's less severe, and allowing the problem to occur when it's most severe.
    Please review this animated diagram of the unique APS twin-vent design and explain to me how its inferior--


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  3. #9947
    UnBanned Sinister's Avatar
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    Quote Originally Posted by Micah View Post
    Uhm.... no

    By doing this, you're correcting the problem when it's less severe, and allowing the problem to occur when it's most severe.
    Micah!

    I'm hoping that was a brain fart dude.

    When open loop you can tune the issue out (At high boost levels, venting to the atmosphere)

    When closed loop the BOV recirculates just like the stocker (Low boost levels recirculating back into the intake tract)
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    Quote Originally Posted by TheJ View Post

    I smelled that one coming.
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  5. #9949
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    Quote Originally Posted by Sinister View Post
    Micah!

    I'm hoping that was a brain fart dude.

    When open loop you can tune the issue out (At high boost levels, venting to the atmosphere)

    When closed loop the BOV recirculates just like the stocker (Low boost levels recirculating back into the intake tract)
    So at open loop you are able to ignore MAF and use MAP? I'm not following. AFAIK the ECU has no way to tell that it should not provide fuel because the BOV has vented to atmosphere.

    Educate me?
    Torch Red 2002 Chevrolet Corvette Z06 46k mi.
    Black 2002 Subaru Impreza WRX 6-speed 94k mi. my mod list
    10/08/2006 - 14.089@103.01 (5-speed with well worn clutch, no launch)
    "Six stars gleaming, five speeds breaking, four tires chirping, three differentials working, two liters screaming, one turbo boosting... it's what makes a Subaru all-wheel-drive, all we'll drive."
    for Bugeye owners my BOV thread Service Manuals

  6. #9950
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    Quote Originally Posted by Micah View Post
    So at open loop you are able to ignore MAF and use MAP? I'm not following. AFAIK the ECU has no way to tell that it should not provide fuel because the BOV has vented to atmosphere.

    Educate me?
    Okay, I could be 100% wrong, so please tell me if I am...

    But the way I understand it, the only true way of tuning this out is by purchasing a hydra, or another 100% open loop engine management system.

    but with a hybrid vta on OL...

    crap... my plane's boarding. I'll finish later...
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  7. #9951
    Registered User Micah's Avatar
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    Quote Originally Posted by Sinister View Post
    Okay, I could be 100% wrong, so please tell me if I am...

    But the way I understand it, the only true way of tuning this out is by purchasing a hydra, or another 100% open loop engine management system.

    but with a hybrid vta on OL...

    crap... my plane's boarding. I'll finish later...
    Maybe you had a brain fart?

    More reading available here:

    So there's NOT ONE engine management system... - NASIOC

    Yes, I agree that an alternative MAP based tuning solution would allow you to run a BOV without the MAF issues. Of course there is the argument that MAP is old tech and MAF is new tech and supposedly more accurate and reliable, but I'm not very knowledgeable about that, at least not enough that I'm about to start making presumptions about the differences between MAF and MAP.

    From what I have seen, the average person looking to add a BOV is expecting they can spend $1XX and up on a new or used BOV and that they can just put it on without any issues. AFAIK - this is not the case. IF they are looking to spend more money and go with an aftermarket tuning solution that uses MAP instead of MAF, more power to them. But I really think most people are misinformed.

    Too many people are quick to say "you can fix it with tuning", and yet I haven't heard of anyone actually doing that. I believe the WRX/STI does have both MAF and MAP sensors from the factory, though I have no idea if the stock ECU can be reflashed in a way that tells it to base fuel on MAP and not MAF. I can say this though - everytime I've looked into a tuning solution for running a BOV it involves going with a standalone and not using the factory MAF - though if someone can find proof that shows otherwise I would love to see it.
    Torch Red 2002 Chevrolet Corvette Z06 46k mi.
    Black 2002 Subaru Impreza WRX 6-speed 94k mi. my mod list
    10/08/2006 - 14.089@103.01 (5-speed with well worn clutch, no launch)
    "Six stars gleaming, five speeds breaking, four tires chirping, three differentials working, two liters screaming, one turbo boosting... it's what makes a Subaru all-wheel-drive, all we'll drive."
    for Bugeye owners my BOV thread Service Manuals

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    Quote Originally Posted by kgelster View Post
    Please review this animated diagram of the unique APS twin-vent design and explain to me how its inferior--

    As long as it does VTA it is allowing metered air to escape, and fuel has already been provided for this air. While having more of the air there is better than less, it's still the same issue - just with an arguably smaller ratio of variance between the air expected, and the air present.
    Torch Red 2002 Chevrolet Corvette Z06 46k mi.
    Black 2002 Subaru Impreza WRX 6-speed 94k mi. my mod list
    10/08/2006 - 14.089@103.01 (5-speed with well worn clutch, no launch)
    "Six stars gleaming, five speeds breaking, four tires chirping, three differentials working, two liters screaming, one turbo boosting... it's what makes a Subaru all-wheel-drive, all we'll drive."
    for Bugeye owners my BOV thread Service Manuals

  9. #9953
    Geriatric Ginger Mod Rogan's Avatar
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    you're right, micah. MAF is the pivotal component to BOV use..
    Run a MAF, and you'll 'never' get it 100% correct, with non-standalone management.
    I've been months, trying every day, to 'tune for it', and am about 90% successful.
    however, that 10%, i cannot correct for, is idle and decel..
    Rogan o_0
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    '01 Dodge 2500 CTD 6-holed hand-shaker - 3850# dual disk - 900 lb/ft - SOLD
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  10. #9954
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    Quote Originally Posted by Rogan View Post
    you're right, micah. MAF is the pivotal component to BOV use..
    Run a MAF, and you'll 'never' get it 100% correct, with non-standalone management.
    I've been months, trying every day, to 'tune for it', and am about 90% successful.
    however, that 10%, i cannot correct for, is idle and decel..


    I'm not sure that standalone engine management is a must. I just believe that as long as the fuel is provided based on MAF signal, the issue with BOV's will remain.

    Every day huh?
    Torch Red 2002 Chevrolet Corvette Z06 46k mi.
    Black 2002 Subaru Impreza WRX 6-speed 94k mi. my mod list
    10/08/2006 - 14.089@103.01 (5-speed with well worn clutch, no launch)
    "Six stars gleaming, five speeds breaking, four tires chirping, three differentials working, two liters screaming, one turbo boosting... it's what makes a Subaru all-wheel-drive, all we'll drive."
    for Bugeye owners my BOV thread Service Manuals

  11. #9955
    Geriatric Ginger Mod Rogan's Avatar
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    I've got hundreds of logs,saved, since Feb., trying to fix my issue with the MAF+3"inlet + BOV
    Rogan o_0
    '96 Dodge 2500 CTD @ 40psi - over 700 lb/ft TQ, 7" stack, and 5speed! - SOLD
    '01 Dodge 2500 CTD 6-holed hand-shaker - 3850# dual disk - 900 lb/ft - SOLD
    '97 Dodge 3500 CTD DUALLY built Auto - 40psi boosties - 750 lb/ft

  12. #9956
    Registered User Micah's Avatar
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    Quote Originally Posted by Rogan View Post
    I've got hundreds of logs,saved, since Feb., trying to fix my issue with the MAF+3"inlet + BOV
    Why not just use a plumb back bpv instead? I've had two different tuner mechanic friends of mine(both shop owners)tell me that so long as the MAF is in use, the BOV will cause issues. Seems like converting away from MAF would be the simplest route to me.

    Blow through MAF ?'s - NASIOC

    Blow Through MAF setup kit - IWSTI.com: Subaru STI Forums

    From reading these threads it looks like going with a blow through MAF setup brings along a new set of issues. Blow by gasses dirtying up the MAF element, and the MAF sensor not scaling properly and winding up at max voltage far below max boost. I know a popular mod with the ford guys has been to throw a larger MAF housing on the same sensor to increase it's effective resolution, is that a possibility here? I know the parts exist - perrin makes a big MAF, and a blow through MAF tube for use with their FMIC.

    More power to you Rogan for doing your own wrenching. The only tool I touch for the most part is my wallet, I let the people I trust guide me and try to make safe choices. Hell I've been on the fence regarding a meth kit for almost a year now. Your way is likely alot more fun, rewarding, and likely cheaper. My way involves alot less effort and a bit more money.
    Torch Red 2002 Chevrolet Corvette Z06 46k mi.
    Black 2002 Subaru Impreza WRX 6-speed 94k mi. my mod list
    10/08/2006 - 14.089@103.01 (5-speed with well worn clutch, no launch)
    "Six stars gleaming, five speeds breaking, four tires chirping, three differentials working, two liters screaming, one turbo boosting... it's what makes a Subaru all-wheel-drive, all we'll drive."
    for Bugeye owners my BOV thread Service Manuals

  13. #9957
    Registered User gushWRX's Avatar
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    BOV to BPV

    is it possible at all to change my TurboXS blow off valve to a bypass valve... i dont want to go through the hassle of taking it off and sellin it and gettin a new one and then putting that on

    i also dont want to put the stock 1 back on because i wanna keep the pshhh sound

    so if there is a way to convert it please let me know how

    thank you

  14. #9958
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    The pssshhhh sound comes from the compressed air being released into the atmosphere. If it vented back into the intake track (as the stock BPV does) you wouldn't hear the noise. I'm afraid you can't have your cake and eat it too.

    As for your question, it depends what model you have. Turbo XS Blow-Off Valves and Adapter Kits, JSC Speed

  15. #9959
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    if you want the psshhhh sound, put the stock BPV on (or the recirculation kit for the TXS) and get an intake... now you have the cake and can eat it too, voila!

  16. #9960
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    bov

    what is the best dump valve for the 2005 wrx sti, i want one that is easy to fit and remove if i sell the car i can put factory fitted one back on. i want one with a distinct whoosh but not to loud

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