3071 surge

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  • prj
    replied
    After 5000 is not surge. When you get surge, the needle actually flutters back and forth.

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  • Audi_CQ
    replied
    Originally posted by A80Avant
    mine sounded excactly like that with a movement of the needle only about 0.6bar. Sometimes its not that easy to notice on a gauge with a needle, and i was noticing it only on the logs.
    Nothing is showing in the logs. Boost is steady all the way. The sound comes at ~5000 long after max boost is achived so can't be surge?

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  • A80Avant
    replied
    mine sounded excactly like that with a movement of the needle only about 0.6bar. Sometimes its not that easy to notice on a gauge with a needle, and i was noticing it only on the logs.

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  • Audi_CQ
    replied
    Originally posted by A80Avant
    that's excactly how surge sounds. Sometimes almost similar to a diverter valve flutter when on lift off.
    That car belongs to a friend of mine and it sound like surge, but boost is completely stable I've observed a couple of 2.2's with GT35 that had surge at ~4000 and 1.8bar and there the boost was all over the place when surge occured.

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  • A80Avant
    replied
    Originally posted by CS Q
    http://www.youtube.com/watch?v=17ZKxHV5Rzs
    This is my car, and you can hear the flutter/chattering sound, on full throttel.
    From 36 sek. and out.
    Claus
    that's excactly how surge sounds. Sometimes almost similar to a diverter valve flutter when on lift off.

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  • QuattroFever
    replied
    .
    Originally posted by prj
    I already wrote that 1.8 bar on stock engine is too much for 0.63 A/R housing.
    You are overstressing the turbo and probably running high EGT's, because I can't imagine you will be able to run much more than 14 deg timing at redline with 0.63A/R hotside and 1.8 bar boost there.

    Leave the spring alone - it seems perfectly fine if your car can actually manage to hold 1.8 bar to redline.

    Going by the sound is also not the correct way. Post a log (graph) of boost vs RPM on the car, if boost does not oscillate when you hear the sound, then it's not surge.
    By the looks of it, your car is perfectly healthy, just needs some mapping efforts.
    Missed this post. Using my phone. Will map some more boost in and get a log.

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  • CS Q
    replied

    This is my car, and you can hear the flutter/chattering sound, on full throttel.
    From 36 sek. and out.
    Claus

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  • A80Avant
    replied
    I had a stock head on the setup I described. Just slightly lower compression.

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  • Thuppu
    replied
    The stock wastegate is adjustable if you pull off the small top cap.

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  • QuattroFever
    replied


    Thats the noise i get although not for as long.

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  • QuattroFever
    replied
    Originally posted by Rusty
    The stock turbo on a 1.5 bar chip gives WG flutter between 3 and 4k RPM or so also, hence asking. If you're running a stock spring, then it might be worth taking advice on an upgraded one.
    I had a high boost high timing chipset from mrc on an all stock setup bar the exhaust and never heard anything quite like this.

    It makes sense though, id like to make it adjustable like i had on my old 3b. A stud in the WG cap to adjust the tension.

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  • prj
    replied
    I already wrote that 1.8 bar on stock engine is too much for 0.63 A/R housing.
    You are overstressing the turbo and probably running high EGT's, because I can't imagine you will be able to run much more than 14 deg timing at redline with 0.63A/R hotside and 1.8 bar boost there.

    Leave the spring alone - it seems perfectly fine if your car can actually manage to hold 1.8 bar to redline.

    Going by the sound is also not the correct way. Post a log (graph) of boost vs RPM on the car, if boost does not oscillate when you hear the sound, then it's not surge.
    By the looks of it, your car is perfectly healthy, just needs some mapping efforts.

    Leave a comment:


  • QuattroFever
    replied
    Originally posted by Rusty
    The stock turbo on a 1.5 bar chip gives WG flutter between 3 and 4k RPM or so also, hence asking. If you're running a stock spring, then it might be worth taking advice on an upgraded one.
    I had a high boost high timing chipset from mrc on an all stock setup bar the exhaust and never heard anything quite like this.

    It makes sense though, id like to make it adjustable like i had on my old 3b. A stud in the WG cap to adjust the tension.

    Leave a comment:


  • Rusty
    replied
    The stock turbo on a 1.5 bar chip gives WG flutter between 3 and 4k RPM or so also, hence asking. If you're running a stock spring, then it might be worth taking advice on an upgraded one.

    Leave a comment:


  • QuattroFever
    replied
    its at 4krpm. Id get a video but u prob wont hear it over the exhaust.

    Do you guys have ported heads? As i understand it you should typically see less pressure at redline if you have headwork or higher lift/duration cams.

    Has anyone measured actual turbo rpm on a stock engine and seen final levels at optimum turbo rpm? Off subject a little but interesting

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