"The BIG BOV thread" (Where all bov question threads get merged) - Page 302
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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; why not? myself and all others i've talked to about it use graphite powder in the cylinder of a bov. ...

  1. #4516
    Registered User Wrinkleboi's Avatar
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    why not? myself and all others i've talked to about it use graphite powder in the cylinder of a bov.
    o-|-<) bryan

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  3. #4517
    Registered User WorxTuning's Avatar
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    Just doing a little surfing this morning and stumbled across this thread.
    While there are some very good points in here, the key factors has only been mentioned a time or two. What is that....BOV design and proper adjustment.
    I am not here trying to plug product, but this thread is a common one on many forums and everyone seems to have a strong opinion, some of which are always a little off base. There are numerous BOV designs on the market, and very few differ in any way except dimensionally. Most use the same basic design and materials to achieve the desired effect, which is to release boost pressure when your throttle plate closes. As it sounds like such a simple function, most companies do not put ample effort into designing one that will work properly with a specific platform (i.e. lets make a flange so we can bolt our BOV onto a WRX as many have done). We have tested every BOV available and there are pros and cons to all of them. Bottom line is that 100% atmosphere is a huge no no. I do not care what anyone says, it is bad news. To get one to function halfway decent, you must make it stiff enough that it releases minimal volume to atmosphere (very stiff). Additionally, most hybrid valves are not much better than a 100% atmosphere valve due to the fact that they open to plumb back and atmosphere at virtually the same time and simple physics tell us that air is going to travel in the path of least restriction. This will vent the majority of air to atmosphere causing very poor results.
    Now, here is where it may sound like I am trying to sell product, but please believe that is not my intention. In the year+ of R&D we put into our BOV before release, we tried 5 designs (yes 5). The only one we found to not cause any negative effect when adjusted properly (that is key) is a staged design such as ours or one like APS. The staged design will run the majority of air through plumb back as stock does, and as boost pressure and air volume increases, the second stage opens and releases excess to atmosphere. Now this will indeed cause an alteration in the A/F ratio as discussed prior in this thread, but if done so in a controlled fashion can have no negative effect and in fact will cool combustion temps a bit during spirited driving. As I mentioned above, the true key to the function is proper adjustment. On our valve we not only have a simple internal spring adjustment, but a rotating atmosphere vent ring that will restrict the volume of air able to pass to atmosphere. I will give you this as an example: on my STi, I run the spring on the #3 setting with daily driving set to 50% atmosphere flow rate and 100% flow rate at times such as going to the drag strip. We only recommend running it at 100% flow when you are in a situation where you will be on and off of the gas quickly such as the drag strip. While function of the atmosphere flow rates remain relatively constant, I used to run the spring on the #2 setting before increasing my boost pressure to 1.4bar. Most companies don't even give you the option of adjustment as their products are a slap on and go part. This is a major design flaw. Every WRX runs differently due to the learning nature of its ECU. This fact is amplified greatly by different driving styles and level of modification. I couldn't tell you the number of e-mails and phone calls we have received over the past 2 years with problems due to improper adjustment. It is generally more novice enthusiasts that did not read the instructions, but seems to be very common none the less. After they get it dialed in you have a very happy camper.
    So, I recommend the following:
    Lube any BOV an a regular basis (yes they require maintenance)
    Take the time to adjust it if yours has this feature
    Don't expect a miracle product that will add gobs of power, at best case it will modify power delivery.

    So the last thing I will talk about is how a bov will change power delivery. Simply put, if you look at your turbo system and the size of the flow paths, then look at the recirculation portion of your system, you will wonder how all of that air will flow through such a small hose upon throttle closing. Well, it won't. The stock bypass valve will vent a portion of air back into the intake, but is still restrictive enough to cause backpressure that slows the speed of the compressor wheel in your turbo. By adding a secondary atmosphere vent, we are able to bleed excess boost pressure to a point that compressor speeds are reduced very little if not at all depending on condition. This REDUCES lag as the turbo is already spooled and when you back off of throttle and then lay back on it you return to almost the same boost pressure that it was before. My wife is scared to drive my car because she rolled a stop sign one day and when she took off it was already capable of pushing enough boost to make the car launch very quickly. What I am trying to say is while a BOV is not a HP adder, a good valve adjusted properly will give a nice increase in power between shifts or on/off power situations.

    I hope this helps someone, and if you have any questions or would like to discuss this topic any further, contact me at Mike@WorxTuning.com

    Thanks
    Mike

  4. #4518
    Moderator MidKnight's Avatar
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    I Support ClubWRX
    Great write-up. Thanks Mike! I have owned an APS and now own a worx valve (it matches the pretty red on my IC piping!) and both are great. Much better than the forge valve I was using.
    '03 WRX
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    "Stuff sold by the gram is always going to be more exciting than stuff sold by the pound." - Jeremy Clarkson

  5. #4519
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    BTW

    I AM that n00b with the bov on a stock car = /

    it lures out the r1ce to come play. I don't use it as a performance mod... its more of a weapon and a necessity where i live. otherwise the guys in the gs-r's won't look twice while i'm blowing by them.

    ALSO. I'm going to have my meghan headers and erz dp installed on friday and i'm going to the track. I want to get in a couple of runs with the Forge BOV i have on and also with stock BPV. maybe see what the differences are.

    Hoping for mid 13's with hearer/up/dp AP2 but who knows i might run a 23.


    back on topic that was a very informative post and tnx
    -burrito

  6. #4520
    Registered User XxScoobYxX's Avatar
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    oh boy BOV's

  7. #4521
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    whats a good choice for a turbo and BOV?

    im 15 years old and im still learning all about cars and companies and all that so i will probly be asking alot of stupid questions but im just a kid who wants to know some stuff so i wont be a poser on the streets... but anyways whats a good turbo for the wrx and BOV?

  8. #4522
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    I read somewhere on NASIOC that 04+ WRX's had a change in the ECU or something and BOV's, MBC's, and CAI can be extremely dangerous for the engine/turbo. Is there any validity in that? Can somebody please clear that up for me

  9. #4523
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    When you look a Subaru engineering-there is NO K.I.S.S. keep it simple engineering. When you can produce a performance car of the caliber of the WRX STi that if maintained will give many years and many miles of trouble free service, this all for a reasonable and affordable pricea can only give accolades to the people in the design center. On the other hand- Mods are fun. Its your car do with it as you wish. But there isn't a magic bullet and there are no free lunches. Mods,even when done well will wear you **** out faster than unmodded. BOV are certaintly not required on a stock car. Big turbos ,ECU changes,FMIC-big power there is a place for them. But imo, ON A STOCK CAR,save your money,keep it full of gas and really learn to use the horsepower it already has.
    Remember: Freedom isn't free.
    Old car: 1999 Porsche 996 C2 coupe
    New Car: 2005 WRX Sti
    Verdict: NO comparison-Sti rules
    Previous race car: Eagle chassis sprint car,410cu in Donovan aluminum smallblock dynoed at 806 hp. car weight. 1375 with the driver. Turn right to go left!!! Sprint car racing-drifting for real!

  10. #4524

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    wrx has a turbo stock
    bov- do a search
    April 04 WRBlue Pearl MT <--"Stitch"
    Mods: Premium Package,STI short shifter and titanuim knob,Momo Airleather shift knob,Rota Formels 17's,AP Stage 2,Coolsafe Thermostat, Apexi Intake, RallyArmor mudflaps, Bosal Cat-back exhaust, Crucial Racing Down-pipe, gold painted calipers,daddy's group buy 3 52mm gagues, center pod, delphi xm radio, JVC CD reciever

  11. #4525

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    April 04 WRBlue Pearl MT <--"Stitch"
    Mods: Premium Package,STI short shifter and titanuim knob,Momo Airleather shift knob,Rota Formels 17's,AP Stage 2,Coolsafe Thermostat, Apexi Intake, RallyArmor mudflaps, Bosal Cat-back exhaust, Crucial Racing Down-pipe, gold painted calipers,daddy's group buy 3 52mm gagues, center pod, delphi xm radio, JVC CD reciever

  12. #4526
    Registered User bluerex47's Avatar
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    if by good turbo you mean aftermarket turbo, check out this page.

    Engine Performance FAQ [[[READ ME]]]

    a lot of people like the 18g. its a sweet turbo, but it pushes a lot of boost. personally, i like the pe1818.

    stock turbo sucks i'm sorry to say
    - chris
    04 wrx, 04 corvette, 66 GTO
    ACT installed at 36k...new Gears at 44k...

  13. #4527

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    its fine for my wrx being stock so far
    April 04 WRBlue Pearl MT <--"Stitch"
    Mods: Premium Package,STI short shifter and titanuim knob,Momo Airleather shift knob,Rota Formels 17's,AP Stage 2,Coolsafe Thermostat, Apexi Intake, RallyArmor mudflaps, Bosal Cat-back exhaust, Crucial Racing Down-pipe, gold painted calipers,daddy's group buy 3 52mm gagues, center pod, delphi xm radio, JVC CD reciever

  14. #4528
    Registered User ramair18954's Avatar
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    Quote Originally Posted by Arclight
    When you look a Subaru engineering-there is NO K.I.S.S. keep it simple engineering. When you can produce a performance car of the caliber of the WRX STi that if maintained will give many years and many miles of trouble free service, this all for a reasonable and affordable pricea can only give accolades to the people in the design center. On the other hand- Mods are fun. Its your car do with it as you wish. But there isn't a magic bullet and there are no free lunches. Mods,even when done well will wear you **** out faster than unmodded. BOV are certaintly not required on a stock car. Big turbos ,ECU changes,FMIC-big power there is a place for them. But imo, ON A STOCK CAR,save your money,keep it full of gas and really learn to use the horsepower it already has.
    yeah, i agree
    03silver wrx fpgreen stg4FMIC+272,272 cams++

  15. #4529
    Registered User 2003WRX's Avatar
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    Well, I've tried a few BOVs. This is my first-hand experience. HKS 100% atm valve, I had it on the car for a few hours, it ran terribly. Major power loss between shifts as the turbo re-spooled. That was sold quickly. Then I bought a GFB hybrid (without the adjustment screw, the older one) and drove around for several months very happy with the performance. Then Worx came around and compelled me to try their brand new BOV. I bought one, and pretty much hated it. The car was very jerky and just generally drove less favorably than it did with the GFB on any setting other than fully closed. I was getting some nice compressor stall too. The Worx was sold, GFB reinstalled. Again, I was content. Then Worx came out with the newer version with the "loud" ring. So I figured I'd give them another shot. The adjustable ring was a nifty idea after all. Once again, disappointment. The car was again jerky and this so-called "loud" ring was a joke. In the meantime I had installed my GFB on my girlfriend's '04 wagon and didn't have the heart to ask for it back, so I bought a new GFB hybrid, this time with the adjustment screw. Yet again, the car ran great with the thing. I sold the Worx again and needless to say my conclusion about their valve is not popular opinion. I think it's a subpar piece of equipment. Just MHO folks, I'm not going to argue about it. I've had two, so whatever. And yes, I did read the instructions and toyed with the settings extensively on both Worx valves.

    Perhaps the most interesting part of my boring BOV history came recently. I decided to put the stock valve back on the car after using the GFB for several months to see just how much better my car would run, according to the "anti-rice" nazis. I left it on for a few weeks and was not particularly thrilled with the way the car ran. It was smooth... sorta. Definitely acceptable in general. So I reinstalled the GFB and everything smoothed out even more so and the car feels better. Therefore I have concluded my car actually runs better with the GFB hybrid than it does with the stock valve. So flame on, but this is fact, for my particular car at least.

    Background engine info on the car: weekend "toy", 8500 miles in 2.5 years, Cobb AccessECU Stage II, TXS stealthback with Prodrive can, Helix uppipe, synth engine oil since 2000 miles. This car is babied and all work has been done by Modern Garage / Cobb Tuning.

    FWIW
    Last edited by 2003WRX; 11-18-2004 at 08:47 AM.
    2003 WRX Sedan
    2004 Nissan Xterra SE 4x4

  16. #4530
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    i like the vf22 the lag that people talk about isnt bad at all spools at about 3300rpms. For a bov it depends if you want a loud, quite, or functional one

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