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Turbo 98 cobra fluttering noise... need help

Discussion in 'Pics and Videos Buffet' started by 98cobra#1222, Jun 28, 2016.

  1. 98cobra#1222

    98cobra#1222 that's just my game Established Member

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    Trying to figure out what this fluttering noise I get from 2000 rpm to 2700 rpm and about 1/4 to 1/2 throttle. It's a fluttering sound that I thought was an exhaust leak but after pressurizing the exhaust and spraying all the v bands with windex I couldn't find any leaks. Has anyone hear a similar sound or have any suggestions of what to try out. Hoping to get it squared away before the car gets tuned in a couple of weeks.


    [video]https://youtu.be/U87lMMAbaJc[/video]
     
    Last edited: Jun 28, 2016
  2. Sonic605hp

    Sonic605hp I have a large member. Established Member

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    I can't hear what you're talking about in the video.
     
  3. byeofcr

    byeofcr Well-Known Member Established Member

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    Throw out bearing be my guess
     
  4. 98cobra#1222

    98cobra#1222 that's just my game Established Member

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    Damn it's really hard to pick up in the video. I'll try to get a better video. In this video if you hear the turbo spool the sound is there just before that, almost sounds more like an air leak than the fluttering sound it makes in person. Perhaps my camera is aliasing the frequency of the sound. You can somewhat make it out when the boost gauge goes above 10 inHg, there isn't any noise at 10 but it starts just above that around 8 inhg.

    Would it be load dependent? I would think the throw out bearing would make noise regardless of load. Is there anyway I could test it without dropping the trans lol


    Sent from my iPhone using Tapatalk
     
    Last edited: Jun 28, 2016
  5. crazycarlo

    crazycarlo Well-Known Member Established Member

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    Have you checked your wastegate to make sure it's opening and the sound isn't compressor surge?
     
  6. 98cobra#1222

    98cobra#1222 that's just my game Established Member

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    No I haven't, but this is running the car up to atmospheric pressure so the wastegates should both be closed the entire time. I also wouldn't think the compressor would surge with the throttle open since it would be operating a good distance from the surge line.
     
  7. 98cobra#1222

    98cobra#1222 that's just my game Established Member

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    Here is a better video of the sound. I've checked all the gaskets and just have a very small leak on the header gaskets. All the v bands are leak free. [video]https://youtu.be/Q4PZgmfjmmw[/video]
     

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