"The BIG BOV thread" (Where all bov question threads get merged) - Page 707

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; Random question...I've noticed while watching the Rally America stages that a lot of the cars have what seems to be ...

  1. #10591
    Registered User AllShallPerishJ's Avatar
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    Random question...I've noticed while watching the Rally America stages that a lot of the cars have what seems to be an unhealthy abundance of compressor surge (the fluttery chipmunk sound). Why does this seem like such a normal occurrence in the highly tuned rally cars? Why wouldn't this be something they would want to dial out?
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  3. #10592
    Geriatric Ginger Mod Rogan's Avatar
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    Quote Originally Posted by AllShallPerishJ View Post
    Random question...I've noticed while watching the Rally America stages that a lot of the cars have what seems to be an unhealthy abundance of compressor surge (the fluttery chipmunk sound). Why does this seem like such a normal occurrence in the highly tuned rally cars? Why wouldn't this be something they would want to dial out?
    what you're hearing is BOV flutter, not compressor surge. This is due to the huge volume/pressure of boost being vented at a rapid rate, and the BOV spring is very strong. the sudden opening causes the BOV piston to 'flutter', or bounce open/closed rapidly, creating the sound you are hearing..


    you can get the same sound, relatively speaking, with an HKS SSQ, and others.. But of course, not recommended on a SUBARU, generally speaking.
    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
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  4. #10593
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    bov

    Hi everyone, I wanted to know if you guys know where i can get that kind of blow off valve with a cylinder? Because i have a tube that is laying there open about 3 inches and don't know where to hook it up to.

  5. #10594
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    Quote Originally Posted by Donkey View Post
    Jesus.........no sounds like a great frigg'n idea.Seriously people,use your head and some common sense and actually try READING some of the info in this thread.
    yeah ok ill sit here and read 3000 pages. i have a job... and a life that does not permit endless hours of internet reading. it was just a question the other character was talkin about running catalytic converters so i asked. haha relax there donkey...
    <------------ Pure unfiltered joy... 04 wrx stage III ** The Blobeye Syndicate **... #39----------------------------------->

  6. #10595
    Registered User Impreza2.0's Avatar
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    Quote Originally Posted by yeap1980 View Post
    Hi everyone, I wanted to know if you guys know where i can get that kind of blow off valve with a cylinder? Because i have a tube that is laying there open about 3 inches and don't know where to hook it up to.
    I think you mean a reciprocal bypass valve. Instead of a trumpet that salutes the local police with your ability to leave them in the dust, the reciprocal bypass valve looks exactly like a blow off valve, and does almost everything that a blow off valve does, instead it blows the charge-air from the intercooler and manifold, and releases it back into the turbine inlet right before the turbine compressor housing. This keeps your turbo spooled, and is an awesome trick. It quiets the turbo, and makes more power at the same time.

    There are fewer BPVs available than there are BOV, but it is easy to retrofit any BOV with a threaded trumpet assembly:

    Greddy Type RS is available with a hardpipe EG return for the trumpet attachment port at the end of it's exhaust tube. It is highly tuneable, and will support up to 50PSI safely.
    It retails for roughly $200.

    Synchronic BOV is a pull type valve which is available for WRX with a return hose attachment built into it. It is also adjustable, they advertise a surgeless and single-piston action release which prevents flutter and surge completely. It is safe to 45PSI.

    HKS has a SSQV, which can be tuned for the WRX, however it is likely that you will still get surge unless you have an experienced tuner rework it's internals.

    I use the Type RS mentioned above, with the helper spring removed, and the tension screw set at only 4 turns. It does not surge, is very quiet until I get turbo happy, which is rewarding with a gunshot loud release of backpressure into the turbine, which spools to 18PSI instantly. I recommend the GreddyRS and GET THE KIT!! It is essential to making bigger power than the stock part. It is the only thing about the valve that is better. The valve itself does nothing to add power whatsoever (it might be a hair faster reacting than the steel OEM valve), but the hardpipe is where the turbine gets better efficiency. The rubber inlet hose from the BPV that came with your car is flexible, will balloon under pressure, this expansion robs power from the turbo at a critical time, during spooling.

    I would not go any further away from a reciprocal bypass type valve than a 50/50 vta. TurboSmart makes several suitable valves for STi and WRX, the 50/50 is tuneable, adjustable, and if you like the sound of blow-off, and don't mind scaring the neighbor's dog, they have a loud sound.

    There are a ton of fakes. Avoid them. They will wreck your car up nicely. Fakes have no quality control, and parts breaking off inside them and goig into your engine is a bad idea, eh? These things are made of small parts which are constantly strained by a pulling or pushing force which will not cease to occur if it breaks. The force will pull the broken piece into another component of your engine, damaging it as well. You risk destroying your turbocharger assembly catastrophically if you put delicate parts in it's vacuum path.

    Another few comapanies to check the websites on:
    Tial
    Turbonetics
    Jackson Racing
    Perrin
    TurboXS
    ARC
    Cobb
    Agency Power
    GReddy/GREX
    HKS
    Synchronic
    A'Pexi
    TurboSmart
    TurboXS

    These guys all make a BOV/BPV that is suitable for use on your car. They also have manned webpages with phone numbers, and can answer your questions very thoroughly, the guys you get on the phone have the parts in their own cars, and are directly involved in designing what they sell. None of the above companies will waste your time with upselling you other unneeded parts, and they will make sure you get what works, not just what makes them another dollar.

  7. #10596
    Registered User psi_guy's Avatar
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    Quote Originally Posted by Impreza2.0 View Post
    In Japan, you will find the best tuners (They got the Impreza before we did) do not go for drag power in a drift car. They also are not nearly as interested in what noise the engine makes as they are interested in what power and for how long.
    Very good point.

  8. #10597
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    Quote Originally Posted by The_Buck View Post
    yeah ok ill sit here and read 3000 pages. ...
    it's only 707, you big baby!
    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

  9. #10598
    Moderator Donkey's Avatar
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    Quote Originally Posted by The_Buck View Post
    yeah ok ill sit here and read 3000 pages. i have a job... and a life that does not permit endless hours of internet reading. it was just a question the other character was talkin about running catalytic converters so i asked. haha relax there donkey...
    The post right above your first one:

    Quote Originally Posted by EJ257
    A quality valve that's properly installed will not do his vehicle any harm, with the exception of if he intends to run catalytic converters. The issue comes from people who get a crappy valve (see: ones that leak), or don't take the time to install / set it up properly.

    Will it benefit a vehicle at a low power level? No. To me, it's wasted money, but it's his car, and if that's what he wants to do, let him do it.
    Then EJ257 posted this just a couple posts up from that:

    BOV FAQ: The REAL dirt on BOVs. Ups AND downs. Lets dispell some myths. - NASIOC

    And this: http://www.clubwrx.net/forums/engine...foramtion.html

    Wow,yeah hours of reading to find that info.Could you be more helpless and lazy?Simpletons everywhere...........
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  10. #10599
    Geriatric Ginger Mod Rogan's Avatar
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    inhale, donkey.. inhale..
    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

  11. #10600
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    Quote Originally Posted by Impreza2.0 View Post
    I think you mean a reciprocal bypass valve. Instead of a trumpet that salutes the local police with your ability to leave them in the dust, the reciprocal bypass valve looks exactly like a blow off valve, and does almost everything that a blow off valve does, instead it blows the charge-air from the intercooler and manifold, and releases it back into the turbine inlet right before the turbine compressor housing. This keeps your turbo spooled, and is an awesome trick. It quiets the turbo, and makes more power at the same time.

    There are fewer BPVs available than there are BOV, but it is easy to retrofit any BOV with a threaded trumpet assembly:

    Greddy Type RS is available with a hardpipe EG return for the trumpet attachment port at the end of it's exhaust tube. It is highly tuneable, and will support up to 50PSI safely.
    It retails for roughly $200.

    Synchronic BOV is a pull type valve which is available for WRX with a return hose attachment built into it. It is also adjustable, they advertise a surgeless and single-piston action release which prevents flutter and surge completely. It is safe to 45PSI.

    HKS has a SSQV, which can be tuned for the WRX, however it is likely that you will still get surge unless you have an experienced tuner rework it's internals.

    I use the Type RS mentioned above, with the helper spring removed, and the tension screw set at only 4 turns. It does not surge, is very quiet until I get turbo happy, which is rewarding with a gunshot loud release of backpressure into the turbine, which spools to 18PSI instantly. I recommend the GreddyRS and GET THE KIT!! It is essential to making bigger power than the stock part. It is the only thing about the valve that is better. The valve itself does nothing to add power whatsoever (it might be a hair faster reacting than the steel OEM valve), but the hardpipe is where the turbine gets better efficiency. The rubber inlet hose from the BPV that came with your car is flexible, will balloon under pressure, this expansion robs power from the turbo at a critical time, during spooling.

    I would not go any further away from a reciprocal bypass type valve than a 50/50 vta. TurboSmart makes several suitable valves for STi and WRX, the 50/50 is tuneable, adjustable, and if you like the sound of blow-off, and don't mind scaring the neighbor's dog, they have a loud sound.

    There are a ton of fakes. Avoid them. They will wreck your car up nicely. Fakes have no quality control, and parts breaking off inside them and goig into your engine is a bad idea, eh? These things are made of small parts which are constantly strained by a pulling or pushing force which will not cease to occur if it breaks. The force will pull the broken piece into another component of your engine, damaging it as well. You risk destroying your turbocharger assembly catastrophically if you put delicate parts in it's vacuum path.

    Another few comapanies to check the websites on:
    Tial
    Turbonetics
    Jackson Racing
    Perrin
    TurboXS
    ARC
    Cobb
    Agency Power
    GReddy/GREX
    HKS
    Synchronic
    A'Pexi
    TurboSmart
    TurboXS

    These guys all make a BOV/BPV that is suitable for use on your car. They also have manned webpages with phone numbers, and can answer your questions very thoroughly, the guys you get on the phone have the parts in their own cars, and are directly involved in designing what they sell. None of the above companies will waste your time with upselling you other unneeded parts, and they will make sure you get what works, not just what makes them another dollar.
    Thank you so much for advise and help on the BOV. I really appreciate that i have a fast reply on it .

  12. #10601
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    Quote Originally Posted by yeap1980 View Post
    Thank you so much for advise and help on the BOV. I really appreciate that i have a fast reply on it .
    He has a few bits of bad advice in this thread. Synchronic are extremely shady (false/fraudulent advertisement) and some of those companies don't even make blow off/bypass valves. And I don't know why he even bothered to recommend anything Agency Power. Also, no, you cannot tune for these valves like he said.

  13. #10602
    Master Baiter EJ257's Avatar
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    Quote Originally Posted by Rogan
    inhale, donkey.. inhale..
    Puff Puff Give
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    "Never trust anything that bleeds for a week and lives ..."

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  14. #10603
    Registered User The_Buck's Avatar
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    Quote Originally Posted by Donkey View Post
    Wow,yeah hours of reading to find that info.Could you be more helpless and lazy?Simpletons everywhere...........
    huh guess i couldnt be more helpless and lazy... oh well
    <------------ Pure unfiltered joy... 04 wrx stage III ** The Blobeye Syndicate **... #39----------------------------------->

  15. #10604
    UnBanned Sinister's Avatar
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    Quote Originally Posted by Donkey View Post
    Could you be more helpless and lazy? Simpletons everywhere...........
    You must work for the DMV....
    Kevin
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  16. #10605
    Geriatric Ginger Mod Rogan's Avatar
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    This isn't NASIOC, fellas..
    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

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