"The BIG BOV thread" (Where all bov question threads get merged) - Page 296
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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; Originally Posted by BigClunke No, I get it. I just think your reasoning is totally wrong and was giving you ...

  1. #4426
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    Quote Originally Posted by BigClunke
    No, I get it. I just think your reasoning is totally wrong and was giving you the chance to admit you really donít know/understand what your talking about before I explained (ill make a new post about this when I have some free time because this is a forum-wide problem).
    Very short-lived rich conditions are really not detrimental to your engine or catalytic converts. Turbo engines need to be rich to maintain temperature. The optimal a/f ratio is about ~13:1 to 14:1 (A: F). Now this should get you thinkin...
    Hey! That would cause catastrophic failure on our engines!
    Thatís right! So how do we manage the heat? Run very rich ~10:1-11:1
    If cats were extremely sensitive then our cars couldn't use them anyways.
    Here is where the misconception stems:
    The more rich a a/f mixture the more work a catalytic converter has to do, this creates more heat and wear on the cat because it is processing more. Cats also donít usually shatter apart when they are spent, they usually clog/restrict and smell awful. That will hurt performance but it should really never reach that point until many years of operation have past. Catalytic converters are not a wear item to be replaced frequently; they are pretty strong and last quite a long time under normal circumstances.
    Do you really think a BOV is going to affect the a/f more than say, a spark plug that has increased its gap .05 due to normal wear? Probably not. I donít have objective data (no a/f gauge) to back that up, but I know what I would put my $$$ on.
    On a side noteÖ
    Shouldnít you be trying to get the stock cats off anyways? They kill performance, I cant even believe how much getting rid of the stock cats helped my performance.

    The intake problem has a lot more merit (and that not saying much). You are altering a tuning device; however. You need to understand how a MAF works to understand why this isnít a huge problem for the ECU to compensate for the change in values.
    A Mass Air Flow sensor is a pretty simple design that heats wire so that them more air flowing into the intake and past the sensor, the cooler the wire will be. From this, you can start to apply it to all kinds of variables and hypothesis how they might affect youíre a/f ratio.
    A CAI will, theoretically generate lower values because more air can cool the heated wire. This is fine and dandy in theory, but often times a very hot engine bay caused by a turbo could heat the wire even more than possible under stock conditions. This causes a extra rich condition in some cases (not very harmful) and a lean condition; if and only if a) the ECU is getting readings out of its range (very unlikely, they are designed to run in the hottest desert and coldest tundra) b) the MAF is getting readings out of its range or c) the MAF sensor is not getting even flow of air and it is giving improper readings (less flow at the top of the intake and more at the bottom.
    The only logical argument is c and I really wouldnít buy it without a flow bench backing that up because if anything it is more even than stock.
    If any loss is noticed it is most likely because of heat soak created by a hot engine bay. Something easily combated by proper heat blocking/removal via heat shields.

    Iím sorry that I had to muck up this post I made about finding these cheap headers by explaining BOV and CAI but as you can see, that attitude is infectious and unfounded.
    I anxiously await your response


    you don't get it and ur misinformed... all u clubwrxn00bs. go on nabisco and read the real info. ur cat WONT MELT. it might get dammaged, but when it gets a lot of fuel thrown at it, it warms up considerably. when it gets too hot, the SH1T holding it into the UP will melt freeing the cat. this causes the cat to go in t3h turbo.

    ur turbo - dead

    happened to a bunch of people who then went to n00baru dealership and got owned because the b0v did it.

    also, turbo cars are not supposed to have a precat... ours is stupid. if u take away the uppipe, the BOV is a good thing. but for people like me (until friday when the meghan headers go in) i am living a life waiting for that day when i will join the n00bs who fried their turbo and can't get the $tealer to warrantee it.

    -burrito

    p.s. ur right they are good things with performance in mind. our cars are stupid and just throwing the two things on there like most 17year old n00bs who just get the car is n0t a good thing. this is why we discourage it.

    p.p.s. i dunno if i made it obvious enough, but the meghan headers/up are coming to me soon.

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  3. #4427
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    Quote Originally Posted by BigClunke
    they might be worthless for performance but so are a whole lot of mods endorced by the clubwrx constituency.
    from a mechanical perspective: Psshht=L0gikk re-circulting=teh ghey
    its only because you associate them with rice that you have a problem, that is how a turbo should sound. youve gone to too much trouble otherwise.



    really? i was only taught about the ones that used a hot wire to get a read out. of course, some different output depending on the type of engine management system.

    remember, people value your opinion alot more than mine; you have a responsibility to make sure everything you say is true and relivant if you seek to combat a valid statement...
    http://www.kemparts.com/TechTalk/tt06.asp



    i wouldn't ever dispute that, but it is a problem when people remain are alowed to remain under the impression that they will ruin your engine. they dont do anything dramatic eitherway you look at it.
    though i need to inquire, what trouble have they caused (or what problems have you heard about)?
    what trouble have they caused? every time i put my aem intake on i knock... then i knock some more.. then the car starts to run like sh1t... then i take it off... then i put it back on later and repeat the process.

    the intake has not been good to me.... and i assume tht many intakes present the same problem.

  4. #4428
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    I was in a car that was run back to back with 2 different BOV's (one 100% atmo and one fully recirc). Just by looking at the change in AFR I could see how that could cause a momentary drop in power. Unfortunately, It's impossible to truly see whether the difference will yield any difference in power. Like I said though, I've personally felt differences in my own car. Since I got my WROX tuning valve I've been going through all the setting and leaving them for a day to see how they affect driveability. Going from fully atmo to fully recirc you can feel a difference in lag after shift. I wish I could quantify it for you but I can't. My buddy couldn't tell the difference from one to the other, but I could. I felt the difference, however miniscule it was.

    I think this just demonstrates the point of this thread though. If you don't notice the difference, then who really cares? Really what it comes down to is each of our own personal enjoyment of driving, not what others tell us we should feel.
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  5. #4429
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    Add this thread to the Engine Performance Sticky. This should be a mandatory read for new members who join.
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  6. #4430
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    very good points. im still using the stock one on 19psi on a p&p vf22 with no leaks. i have had the hks ssq and the turbo xs rfl. even with them being set right for correct boost settings it still seems it has the most power with the stock one.
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  7. #4431
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    i have a forge Diverter valve not a bov, also apexi intake it doesnt mess up anythin

    Quote Originally Posted by dark_rex
    couple comments.



    hmm. that's nice. got a dyno sheet to back up your butt dyno? i've seen many. they all show varyind degrees of torque loss / shifting. still haven't seen one for the megan headers... so take it easy on the "retarded" comments.

    bov's are generally worthless performance wise we discourage them b/c we like to see suby tuners worrying more about going fast, cornering faster, and stopping quicker. psshht! = teh ghey

    there are a few different types of MAFs.

    intakes are not NECESSARY until later in the mod curve. anyone worth their salt will tell you they're fine in the right conditions. without a dyno tune (and the right intake) many dyno tuners will tell you that they are more trouble than they are worth.

    stinky cats STINK!

    that is all.

    dR

  8. #4432
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    Quote Originally Posted by ramair18954
    very good points. im still using the stock one on 19psi on a p&p vf22 with no leaks. i have had the hks ssq and the turbo xs rfl. even with them being set right for correct boost settings it still seems it has the most power with the stock one.
    I'm not surprised that your stock BOV is holding at 19psi. The wrx bov is very similar in design to the bov on turbo dsm's (other than the evo) and it's well documented that they will start leaking around 20psi.
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  9. #4433
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    just to add

    the headers touch the oil pan, so what i am going to have to do is dent the headers slightly so they dont touch in two days the pans paint has already rubbed off from the heat. and you know its cooking the oil in the pan. ill let yall know i was going to just dent the pan but then i was afraid of puncturing the pan, its pretty thin **** so i dont wanna **** it up

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  11. #4435
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    i think my short ram makes a better blow off sound anyway. plus my car is a lot more sleeper.
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  12. #4436
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    Quote Originally Posted by scoobaru
    the headers touch the oil pan, so what i am going to have to do is dent the headers slightly so they dont touch in two days the pans paint has already rubbed off from the heat. and you know its cooking the oil in the pan. ill let yall know i was going to just dent the pan but then i was afraid of puncturing the pan, its pretty thin **** so i dont wanna **** it up
    wrapping/ coating (like jethot2000) might help that.

    either way, that's not a good thing!

  13. #4437
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    Quote Originally Posted by BigClunke
    i havent encountered any maf's that look like the vane type. i dont remember them being discussed in diagnostics and tune up... my mistake.
    what types of cars use a vane typed meter?

    foreign and domestic cars have used / use vane type mafs. i think mustangs used to. i do know they only work with electronic fuel injection. i can't remember why, but older carburator cars used a hot wire method.

    perhaps it's got something to do with the measurement differences... ie: a vane measures in cfm units rather than volts.. i'm not really sure though.

    [/hijack]

    dR

  14. #4438
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    Quote Originally Posted by Trailboss
    Add this thread to the Engine Performance Sticky. This should be a mandatory read for new members who join
    uh no.

    Quote Originally Posted by BigClunke
    (turbos reuse exhaust gasses, therefore, what is blown off is a mixture of re-circulated gasses and fresh air).
    Thats just a really stupid comment.

    Quote Originally Posted by BigClunke
    Truthfully, i am very new to the turbo charging process.
    Then why post a long report on mythbusting a serious issue (as you put it) instead of researching how it even works.
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  15. #4439
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    clearly, i have a very good idea of how an engine works, i wouldnt have been able to write all of that if i hadn't. just because i was alittle unclear about forced induction dosent mean i dont know what im talking about at all
    thank you for contributing positivly to this thread

  16. #4440
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    i can assure you that mustangs with EEC-IV uses a hot wire system. i have worked extensivly on a variety of fords (i learned on them) they used speed density before eec iv which was later replaced by eec-v, which i think they are still using. i really think that vane style maf's are pretty uncommon, but i am willing to hear otherwise (not that this point even really matters)
    burrito,
    your calling me a noob? i dont even think you can hang with my nomenclature, you just see some words you recognize and flame me based on thoes, kinda weak huh?
    (did you really not understand what i said, cause ill clarify it if you want me to?)
    oh btw, if i want to argue the bov you can continue to be negative in the new thread i made.

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