"The BIG BOV thread" (Where all bov question threads get merged) - Page 712

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 mrkenny SO................. over the last 7+ years of this thread going on WHAT have we determined about ...

  1. #10666
    Registered User Impreza2.0's Avatar
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    Quote Originally Posted by mrkenny View Post
    SO................. over the last 7+ years of this thread going on WHAT have we determined about running a BOV on your Subaru???

    i've read they are OK, i've read they are BAD......

    I'd like a little noise when i'm changing gears to let people know what i got... but at the same time i only want the VERY BEST for my motor and air/fuel ratio and etc...

    from what i've learned i'm thinking a 50/50 valve would be best... but even these? do they mess up the air/fuel ratio when they do open all the way and bleed air out both paths???

    THANX GUYS
    You want a bypass valve, not a blow off valve. You will create issues galore with a stock setup by just adding a BOV. There are some BPVs that can be converted into BOVs, and vice versa, they are only the high-end pieces, like GFB, Perrin, GReddy...

    I have a GReddy, it sounds awesome, it is a bypass valve, looks like a blow off valve.

    If I ever get a FMIC, it can be made into a blow off valve by removing the reciprocator pipe and screwing the trumpet back into the port.

    Plugging the gas return to the turbo will just create agony.

    You need to read this whole thread, honestly. It will slowly show you why.

    There has been endless trial and error with this. Until you have a post TB MAF, you are going to run rich, stall, go into limp-mode, other torment...

    The many brands with convertible valves leaves you to know only what you know now, and be safe with a good upgrade. Until you are running over 24psi, there is no use, though, the stock piece is good to 24psi. After that it is a valve issue.

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  3. #10667
    UnBanned Sinister's Avatar
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    Quote Originally Posted by Impreza2.0 View Post
    You want a bypass valve, not a blow off valve. You will create issues galore with a stock setup by just adding a BOV. There are some BPVs that can be converted into BOVs, and vice versa, they are only the high-end pieces, like GFB, Perrin, GReddy...

    I have a GReddy, it sounds awesome, it is a bypass valve, looks like a blow off valve.

    If I ever get a FMIC, it can be made into a blow off valve by removing the reciprocator pipe and screwing the trumpet back into the port.

    Plugging the gas return to the turbo will just create agony.

    You need to read this whole thread, honestly. It will slowly show you why.

    There has been endless trial and error with this. Until you have a post TB MAF, you are going to run rich, stall, go into limp-mode, other torment...

    The many brands with convertible valves leaves you to know only what you know now, and be safe with a good upgrade. Until you are running over 24psi, there is no use, though, the stock piece is good to 24psi. After that it is a valve issue.
    A recirculating valve won't make any more sound than the stock recirculating valve. If you're not over 20psi then you're fine. 20 psi is generally regarded as the safe cut off without doing the "crush mod" to increase spring tension.

    OP don't waste ANY money on an after market BOV. You'll run rich shifts... ruin your catalytic converter, idle poorly, mildly increase cylinder wear, increase hesitation between shifts... I can keep going and going... there isn't a single good reason for an aftermarket BOV on the stock ECU. Even a Cobb or Utek can't do anything for you.
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  4. #10668
    Master Baiter EJ257's Avatar
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    Quote Originally Posted by Sinister
    Yes... only on large turbos tho, and it depends on the diameter of the intercooler piping that you'll be putting the MAF in. The smaller the piping, the more flow rate, and the higher the MAF voltage is going to be.
    Yeah, larger piping is the answer if you're maxing your MAF (similar to if it's in an intake)

    Quote Originally Posted by Sinister
    But also... more importantly... oil blow by. You'll be cleaning your MAF sensor a lot more frequently because the PCV system is dumping in front of the MAF now, and turbos are always blowing by small amounts of oil.
    A/O Sep - all the high HP Subarus I know are running them.

    Quote Originally Posted by Sinister
    OP don't waste ANY money on an after market BOV. You'll run rich shifts... ruin your catalytic converter, idle poorly, mildly increase cylinder wear, increase hesitation between shifts... I can keep going and going... there isn't a single good reason for an aftermarket BOV on the stock ECU. Even a Cobb or Utek can't do anything for you.
    Meh
    Last edited by EJ257; 07-27-2009 at 07:08 PM.
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  5. #10669
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    Quote Originally Posted by Impreza2.0 View Post
    Plugging the gas return to the turbo will just create agony.
    What the hell are you talking about...

    There is no gas return line into a turbo.


    Are you referring to the hose from the Recirculating Bypass Valve into the Turbo Inlet Hose?
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    cool. so for now i'm gonna delete that airbox silencer bullcrap, and stick with a stock bpv!!! i think thats the best route for me to take right now without spending money on a k&n intake system

    does this sound correct guys???
    thanx 4 all the help
    2006 Subaru Impreza WRX STI alpine white

  7. #10671
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    Quote Originally Posted by mrkenny View Post
    cool. so for now i'm gonna delete that airbox silencer bullcrap, and stick with a stock bpv!!! i think thats the best route for me to take right now without spending money on a k&n intake system

    does this sound correct guys???
    thanx 4 all the help
    Yesssir.
    -kyle
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    VF39'd, Bailey-tuned! 280.07whp 250.05wtq

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    Quote Originally Posted by mrkenny
    cool. so for now i'm gonna delete that airbox silencer bullcrap, and stick with a stock bpv!!! i think thats the best route for me to take right now without spending money on a k&n intake system

    does this sound correct guys???
    thanx 4 all the help
    When tuned properly, there are gains to be had on a custom-tuned StageII STi setup. If you still are on the stock exhaust, an intake looks/sounds nice, but doesn't do much else.
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  9. #10673
    Registered User mrkenny's Avatar
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    Quote Originally Posted by Impreza2.0 View Post
    You want a bypass valve, not a blow off valve. You will create issues galore with a stock setup by just adding a BOV. There are some BPVs that can be converted into BOVs, and vice versa, they are only the high-end pieces, like GFB, Perrin, GReddy...

    I have a GReddy, it sounds awesome, it is a bypass valve, looks like a blow off valve.

    If I ever get a FMIC, it can be made into a blow off valve by removing the reciprocator pipe and screwing the trumpet back into the port.

    Plugging the gas return to the turbo will just create agony.

    You need to read this whole thread, honestly. It will slowly show you why.

    There has been endless trial and error with this. Until you have a post TB MAF, you are going to run rich, stall, go into limp-mode, other torment...

    The many brands with convertible valves leaves you to know only what you know now, and be safe with a good upgrade. Until you are running over 24psi, there is no use, though, the stock piece is good to 24psi. After that it is a valve issue.
    WHOA i never said anything about a gas return line to the turbo! i'm not stupid!!! where did u get that from???
    2006 Subaru Impreza WRX STI alpine white

  10. #10674
    Wrinklechops
    Quote Originally Posted by Sinister View Post
    Oil isn't a problem if you oil it properly. Over oiling can happen on any intake filter.
    Supposedly you're not supposed to use oiled filters on our car, period.


    Bout to head out of here. What're you doin?
    Trying to locate the previous owner of my car.

  11. #10675
    Registered User Impreza2.0's Avatar
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    Get a really pretty short ram intake. It will eliminate everything under the hood that keeps you from hearing the valve. Your valve is a good one, albeit not pretty, you can ruin your engine with a cold-air intake, and the stock airbox is restrictive. Your MAF sensor will freak out with a cold air intake... it is not able to measure air volume and velocity properly with them without a tuning done at the same time as the installation of it.

    With a short ram, you get even air flow, your air flow sensor has no problems, and you don't need a tune.

    GReddy Type RS Recirculating BOV is perfect for you if you want the looks and the sound. My GReddy piece did make the sound a little louder, since it replaces the rubber hose to the turbo with Aluminum, and is a bit snappier. It is also adjustable, so as you get more go-fast parts, it can keep up. Then when you get a FMIC and a giant ball-bearing turbo and it's required supporting mods, you can keep it, and adjust to each mod as they come in.

    There aren't any other valves that have this pipe, it is unique, and not sold separately to my knowledge.

    GReddy Type RS Recirculating BOV Kit for 02-07 WRX & 04-09 STi, WRX Blow off Valve from JSC Speed

    These guys know their stuff. I buy from them, and I trust them. They don't gouge you on prices, and won't sell you something that can break your car. Tell them what you have. Ask questions.

    I went through a hard time finding a valve I was happy with, I called these guys, and they really helped me understand the system, and how to upgrade it without being an idiot. They also believe in using real parts, not knock-off eBay junk, and that an engine is only as good and reliable as it's parts.

    They race STi Imprezas, so this is a safe bet.

  12. #10676
    Registered User Impreza2.0's Avatar
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    double posted
    Last edited by Impreza2.0; 07-27-2009 at 07:28 PM.

  13. #10677
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    A 50/50 will only vent 50 percent of the released pressure to atmosphere, the other 50 to the return-pipe. Your turbo is designed to receive air during shifts so that it will remain spooled. Unless you are rebuilding the entire turbo system, it is wise to stick with the bypass type system. Yes, you can do the MAP mod, but that comes with many others at the same time. It would do you endless good to read this thread from the beginning. These questions have been asked countless times, and there are how-tos, photos, lists of brands, places to buy, professional mechanics and racers have given their input, and it is more valuanle than any. We (daily drivers) will try to help you not to have to search and search only to find a few words on the subject, but we have all been through what you are going through. Some have bitten the bullet and done all of the work to install an uprotated turbo mount, after-maf intake, etc.

    Even then, there are a lot of financial considerations. That sound is loss of spool during shifts, something Subaru was genius to fix, and backpeddling technology to sound like a cannon in traffic is really a waste of money, will invite tickets, and will get you smoked by a properly tuned stock STi.

  14. #10678
    Registered User Impreza2.0's Avatar
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    Quote Originally Posted by mrkenny View Post
    WHOA i never said anything about a gas return line to the turbo! i'm not stupid!!! where did u get that from???
    Most of the BOVs around require you to plug the exhaust-gas-return line to your turbo. This is fine if you have a post MAF intake, but you don't. Not gasoline, GAS. Air in other words.

    The return pipe to your turbo is not necessary, but increases turbo performance. It keeps it spooled while you shift.

    Really, get an intake, and you will smile. You will make 5 or 10 horsepower, and get that PSSHHHHT sound that ratchets the necks of the elderly when you pass them.

  15. #10679
    UnBanned Sinister's Avatar
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    Quote Originally Posted by Impreza2.0 View Post
    Get a really pretty short ram intake. It will eliminate everything under the hood that keeps you from hearing the valve. Your valve is a good one, albeit not pretty, you can ruin your engine with a cold-air intake, and the stock airbox is restrictive. Your MAF sensor will freak out with a cold air intake... it is not able to measure air volume and velocity properly with them without a tuning done at the same time as the installation of it.

    With a short ram, you get even air flow, your air flow sensor has no problems, and you don't need a tune.

    GReddy Type RS Recirculating BOV is perfect for you if you want the looks and the sound. My GReddy piece did make the sound a little louder, since it replaces the rubber hose to the turbo with Aluminum, and is a bit snappier. It is also adjustable, so as you get more go-fast parts, it can keep up. Then when you get a FMIC and a giant ball-bearing turbo and it's required supporting mods, you can keep it, and adjust to each mod as they come in.

    There aren't any other valves that have this pipe, it is unique, and not sold separately to my knowledge.

    GReddy Type RS Recirculating BOV Kit for 02-07 WRX & 04-09 STi, WRX Blow off Valve from JSC Speed

    These guys know their stuff. I buy from them, and I trust them. They don't gouge you on prices, and won't sell you something that can break your car. Tell them what you have. Ask questions.

    I went through a hard time finding a valve I was happy with, I called these guys, and they really helped me understand the system, and how to upgrade it without being an idiot. They also believe in using real parts, not knock-off eBay junk, and that an engine is only as good and reliable as it's parts.

    They race STi Imprezas, so this is a safe bet.
    Stopp STOPP STOP!!!


    OP... Don't get one of these. Your ECU works fine with the one you have right now. You don't have to tune your stock one. You're not over 20lbs of boost. There is absolutely no reason to blow money on something as moot as this.

    Impreza2.0 is just trying to make himself feel good for purchasing something that he didn't need... and trying to make himself feel like he didn't waste money. But he did.


    If you like to waste money... go for it.

    Otherwise... "If it ain't broke, Don't Fix It!!"
    Kevin
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    Sinister's Blowoff Valve FAQ
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  16. #10680
    Registered User mrkenny's Avatar
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    Quote Originally Posted by Impreza2.0 View Post
    Most of the BOVs around require you to plug the exhaust-gas-return line to your turbo. This is fine if you have a post MAF intake, but you don't. Not gasoline, GAS. Air in other words.

    The return pipe to your turbo is not necessary, but increases turbo performance. It keeps it spooled while you shift.

    Really, get an intake, and you will smile. You will make 5 or 10 horsepower, and get that PSSHHHHT sound that ratchets the necks of the elderly when you pass them.
    GOT YA NOW... i was like GAS??? i'm not that dumb to dump gas into my turbo!!! lol
    2006 Subaru Impreza WRX STI alpine white

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