Car Freaks!!

Discussion in 'The Guru's Pub' started by AJ²06, Jan 2, 2005.

  1. Cornelius

    Cornelius Master Guru

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    Read my post above... I agree, BOVs are definitely a dumb mod if you're hanging onto your stock turbo. The stock bov will easily sustain 400+ whp.

    -2005 WRX (see avatar), AP+stage2, TBE, catless up and a few others... next on the list is a new TMIC.
     
  2. heads_up

    heads_up Ancient Guru

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    What are you talking about???

    A BOV is there to release the excess air (boost) in the pipe as the engine doesn't need it, the better the BOV the wider the valve so the air can escape faster so that when the engine draws for air (vacuum) it takes directly cold air from the intercooler rather than slightly warm air sitting in the pipe, and colder air is denser and is better for combustion.

    In a Mitsubishi Legnum VR4 Twin Turbo we added a very large BOV and we saw a decent increase in power just from that. Not to mention every time we went into town we would always "slap" other cars with the BOV and we would always win, even with completely stock turbos.
     
    Last edited: Apr 17, 2007
  3. r0k0

    r0k0 Ancient Guru

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    dude you dont even need a bov... BOV are for show off... if you want a sleeper... put your whole car turbo and no bov.. when you race the will likely not notice the turbo because you'll be around 200-300 yards in from :)

    i want a BOV too in my new Twin Turbo RX-7 engine :p
     
  4. heads_up

    heads_up Ancient Guru

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    You need a BOV with a turbo, if you can't get a BOV, get a bypass valve, if you can't get either put a whole in the tubing otherwise you will **** your whole engine, like if you have a DOHC engine, the pressure put on your valves when there is not release for the boost will push them open, either breaking the cams, or worse, and then your valves will be down when your pistol comes up, and then your fuxzored

    However Rotarys are fine without a BOV, it can screw up, but most of the time it will be sweet as, but if the pressure caused by the turbo on the inlet of the chamber pushes the rotor even 1mm around too far the combustion won't happen properly and then the rotor won't make it around for the next combustion and then your screwed again....

    Also the air to fuel ratio will be way off and the explosion caused won't be enough to push the pistol down and you will be screwed again

    So basically a BOV is compulsory
     
    Last edited: Apr 17, 2007

  5. Cornelius

    Cornelius Master Guru

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    A Subaru WRX is not Mitsubishi VR4 or a turbo RX-7. For a WRX or even an STI, the stock BOV is fine unless you're pushing more than 20+ psi.

    I wasn't saying you don't need a BOV. They're necessary to keep a sudden closed throttle from creating compressor surge.

    Aftermarket BOVs may cause the car to run too rich (too much fuel, not enough air) when suddenly lifting off the gas, which can cause catalytic converters to melt/break down. To be more specific, many aftermarket BOVs (especially the loud ones) are external, which mean they dump the air back into the atmosphere, rather than back into the intake (pre-turbo). This is much more inefficient than the stock BOV, and because of this, you may be running richer than you would like (waste of gas too). A tune won't fix this either... the mass air sensor is measuring the wrong amount of air being sucked in, and sends in too much fuel. (Am I clear, or do I need to go into more detail?)

    If you want the ricer BOV sound, the snorkel mod (aka: intake silencer/elbow delete) will allow you to hear the stock BOV, as well as the turbo spool.

    Again, this is personal experience. I've been under the hood my wrx many times (did all my mods myself) and have listened to numerous professional tuners tell me what works and what doesn't.

    But hey, it's your car.
     
    Last edited: Apr 17, 2007
  6. heads_up

    heads_up Ancient Guru

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    Thats called a "by pass valve" which was mentioned in my post before.

    And whens it comes to Sub'ies I owned a Legacy RS for about 2 months, that thing was loud, but on stock turbo was unless, it ran 14PSI and had like no pull. It had a nice BOV, really loud, but they tend to draw to much attention. It had a 38mm external wastegate as well, I got pulled over 4 times in the first 3 days of owning it, and I was just crusing, not even speeding!
     
  7. Cornelius

    Cornelius Master Guru

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    Fair enough... I've been drinking tonight, and I'm a mean drunk. I've always confused BPV/BOVs.
     
  8. DeatHRattlE

    DeatHRattlE Maha Guru

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    The use of blow off valves depends on turbo output and engine its on. Some of the earlier fords that got turbos did not have a valve at all. The engine could swallow anything the turbo could throw at it at anytime. It never sounded right to me but thats the way it is with them. For whatever reason even when I am looking at the whole turbo system it still doesn't make sense to me. You would think they would at least put a valve on for fun.
     
  9. heads_up

    heads_up Ancient Guru

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  10. Satan

    Satan Ancient Guru

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    Nice! There's this too:
    http://www.howstuffworks.com/question259.htm

    Apparently my cousin's new A8 W12 has a NoX booster built in (at his request from his auto mechanic) for the purpose of "Smoking hot shots in their 'street racers,' teaching them what you can do with a real car."
     

  11. Used_condom

    Used_condom Master Guru

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    saleen S7 TT.. awesome car that looks awesome too
     
  12. Satan

    Satan Ancient Guru

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    Super expensive though, considering you can get a 1000bhp Skyline for 50-100 grand :D
     
  13. kwak

    kwak Ancient Guru

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    and how long does that 1k bhp skyline engine last?
     
  14. Satan

    Satan Ancient Guru

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    Who knows, I guess long enough to see you do 0-200 in like 13sec and crash it into a phone pole at 14 :D
     
  15. kwak

    kwak Ancient Guru

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    lol, superb reply!!
     

  16. Satan

    Satan Ancient Guru

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  17. AJ²06

    AJ²06 Ancient Guru

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