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Thread: Running no BOV for track duties

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    Running no BOV for track duties

    Maybe a dumb question but anyone successfully running with NO BOV on their Evo X. Providing the turbo can handle the extra stress are their any other reasons why not? Wasnt sure if this would screw up the tune maybe interfere with the MAF sensor. Everything I've read & data I've seen suggests quicker spool when not running one.

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    It's quicker spool when you are running one.

    The pipe might stay more charged but when you close the throttle the air has no where to go up back through the compressor in the wrong direction.

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    Senior Member razorlab's Avatar
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    Make sure you have a pile of turbos you can bring with you to the track so you can swap them out quickly.

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    LOL curious as some manufacturers such as Holset claim no BOV required due to thrust bearing arrangement.

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    Global Mod of Things DKevoX's Avatar
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    Quote Originally Posted by 4B11T View Post
    LOL curious as some manufacturers such as Holset claim no BOV required due to thrust bearing arrangement.
    Got a source??

    I can't think of any advantage to not running a bov/cbv.

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    Not sure how/why but the BMW B58 engine in a newer 340i does not have a BOV. Maybe they get away with it by having an electric wastegate?

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    Senior Member razorlab's Avatar
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    Quote Originally Posted by Ford4door View Post
    Not sure how/why but the BMW B58 engine in a newer 340i does not have a BOV. Maybe they get away with it by having an electric wastegate?
    "Pressure peaks, caused by sudden load shedding due to the inertia of the turbine of the exhaust turbocharger, can be avoided by careful tuning of the Digital Motor Electronics software. With foresighted charging pressure control, pressure peaks can be predicted and reduced by quick adjustment of the electrically-adjustable wastegate valve. Assisted by a delayed load control of the Valvetronic (in the minimum lift direction) or the throttle valve (in the closed direction), the remaining charge air which is produced can be routed to the exhaust emission system via the engine. This form of control thus prevents the exhaust turbocharger shaft from being exposed to excessive torsional stress due to high pressure peaks."

    Not just the e-wg doing the job here.

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    yup the f80 m3/4 makes those fart noises cause it's burping the air through the engine via tricked up valve wizardry.
    Last edited by momo; 05-13-2018 at 09:33 AM.

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    A local turbo guru which uses Holset a lot frequently use no BOV's on performance car builds. I gather the bearing arrangement they use can take the abuse - I must ask if this is official "Holset" information or personal opinion.

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    I've heard of MR2 guys doing this, but i suspect it may make throttle more difficult to modulate midcorner.

    I remember my BOV used to stick for some weird reason, and sometimes when i'd touch the trottle midcorner, it felt like there was all this built up pressure that got released into the intake and would sometimes make all 4 wheels chirp which would send me rocketing out in a 4 wheel slide on corner exit. Definitely not fast, and the last thing you'd want when you're modulating throttle or easing on throttle mid corner.


    Funny thing, my 1st engine started going out and would have all sorts of oil blow by enter the intercooler pipes. My BOV stopped sticking once the blow by started to occur and hasn't been stuck since.

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    Next time you're at the track, try removing the BOV for a session or a couple laps to test. I'm sure it can't hurt so long as you quit early.

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