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Thread: bov springs?

  1. #1
    Chassis Designer
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    Jun 2007
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    Default bov springs?

    I got a greddy rs knockoff which works, but I'm still having compressor surge before boost. I need to know a place where I can get generic compression springs to try and match it with what I need. I've tried all the tricks too, shimming, messing with the adjustment screw, cutting/removing the softer spring. Ace Hardware has these dime size (diameter-wise) springs that I've been having luck with, but they have too many coils. I've searched mt.net/google but couldn't find anything : /.
    Last edited by popopo; 12-04-2009 at 08:52 PM.
    '95R

  2. #2

    Default

    I refuse to call blow off valve cute flutter noise "compressor surge." Compressor surge is bad when the turbo is loaded up, when there's say 25-40psi of pressure in the manifold/turbine housing. It sounds like a hammer because the turbo is turning 130,000rpm, with 300* compressor outlet air temps.

    When the motor is in vacuum and you get the BOV flutter noise, no damage is occurring because the turbo is "freewheeling" and the noise is primarily from a partially open valve and its just air noise...not the compressor working as a brake.

    Discuss if you want, I've read a lot about this because I'd rather have my BOV closed in cruise than sucking in sand.
    TXMC: Drinkin, shootin, racin!

  3. #3
    Chassis Designer
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    Default

    The bov is soft enough to vent at idle, but just not enough where I can hear an audible noise, making me think I need a slightly stiffer spring. Shimming the spring sucks because I lose travel length on the valve itself. If you're saying that because my BOV is partially open at vaccuum and I'm getting that noise, then I'll leave it at that. I do have maybe 2 mm of gap in idle, not enough to where I can feel any air coming out, but enough where I know it can be close more.

    I could care less about my turbo itself right now because I've still haven't finished gotten the car to run right lol. Btw, my garage is much cleaner, got a whole bunch of rails and a toolbox, and a few more power tools : ). Thanks mr brg!
    '95R

  4. #4
    Chassis Designer
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    Default

    Heh, after googling 'bov flutter' it seems to be the BOV and not the turbo. Thanks!
    '95R

  5. #5

    Default

    The noise is from the turbo, but you can hear it because the valve is partially opening and closing quickly. You need to put in a firmer spring to that its closed in cruise. I had very high silicate #'s in my last oil analysis due to the BOV letting unfiltered air into the engine at cruise.

    Let me know if you need help with anything else.
    TXMC: Drinkin, shootin, racin!

  6. #6
    Chassis Designer
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    Arlington
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    Default

    Yeah, I'm getting mixed things from google, but I understand it better now. I still need a stiffer spring from somewhere, I'll hit up Home Depot later.
    '95R

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