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S3 Turbo Chattering Under Acceleration..!?

Discussion in 'A3/S3/Sportback (8P Chassis)' started by Gaz-M, Jun 20, 2014.

  1. Gaz-M
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    Gaz-M Member

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    [Jun 20, 2014]
    Ive just fitted a Revo intake to my S3 and now it lets you hear all the turbo noises i can hear what sounds like a wastegate chatter - but whilst im on full throttle!

    Its almost as if the diverter valve is chattering open and closed allowing boost back to the intake pipe and giving me the noise. Anyone had this?

    Ive also done Revo PCV delete and rev D diverter valve.

    Going for a stage 1 Revo map tomorrow!

    Ill see what its like after remap.
    #1
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    [Sep 15, 2014]

  3. wuta3
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    wuta3 Well-Known Member

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    [Jun 21, 2014]
    Isn't that how boost pressure is regulated at full throttle? ie by opening/closing the DV to maintain around the requested pressure?
    My pressure charts always show a climb then an up/down/up/down at peak pressure.

    Not that I know anything about these things.
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  4. batch
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    batch Active Member

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    [Jun 21, 2014]
    Fairly normal on these mate, my Neuspeed CAI does it with Shark stage 1
    #3
  5. Aqualea90
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    Aqualea90 New Member

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    [Jun 21, 2014]
    I have had exactly the same problem and am in a panic about it. I was wondering do you need a specific remap for the CAI?? My car almost feels a little under power as well. DV valve is fine on mine too.
    #4
  6. Gaz-M
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    Gaz-M Member

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    [Jun 21, 2014]
    Cheers, just weird that my Mk5 Golf never done it!
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  7. mechanic69
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    mechanic69 Active Member

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    [Jun 21, 2014]
    My REVO does the same, sounds good mate!!!
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  8. Gaz-M
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    Gaz-M Member

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    [Jun 24, 2014]
    Sounds wrong though, sounds like its dumping boost which isnt what you want on full throttle!
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  9. Marshy
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    Marshy Active Member

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    [Jun 24, 2014]
    Was your Golf an Ed30 or standard GTI?
    If it was a standard Gti they never done it due to the different way the dv was setup.
    My S3 does it and my previous Cupra R (same engine) done it.
    Just boost being regulated by the dv.
    #8
  10. Aqualea90
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    Aqualea90 New Member

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    [Jun 24, 2014]
    My car has only done it since the CAI has been fitted. I replaced the old engine cover the other day and it made the same noise just not as loud. It didn't used it do it. Was yours the same Gaz?
    #9
  11. mechanic69
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    mechanic69 Active Member

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    [Jun 24, 2014]
    I'm sure sound in the intake and back from the turbo is Amplified by the cai, the standard air box cuts all the noise out. You just notice it more now
    #10
  12. S3_Mat
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    S3_Mat Active Member

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    [Jun 25, 2014]
    Sounds like its mapped on the surge line.. Its normal apparently.. Mine does this as well.. Does it only happen WOT in higher gears around 3-4k revs?
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  13. S3Alex
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    S3Alex Rarely neutral

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    [Jun 25, 2014]
    I'd agree with that.

    On my old K04,the car would do that,and to an extent with the GT3071,but the current 3076,with it's anti-surge housing etc,doesn't have any issues.
    #12
  14. RedDejavu
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    RedDejavu Well-Known Member

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    [Jun 25, 2014]
    happens to mine too, I run Revo CAI apparentley there is too much air trying to get into the engine which turbo cannot force in. It wont damage the engine and is fine to drive with it.
    #13
  15. mechanic69
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    mechanic69 Active Member

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    [Jun 25, 2014]
    I'm no expert but physics is driving this. I wouldn't say "too much air trying to get in". The turbo is the drive for the air, it will push as much as can it can force into the engine. The CAI removes the stock air box allowing the turbo to take as much air as it needs.
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  16. Marshy
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    Marshy Active Member

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    [Jun 25, 2014]
    The noise only occurs 4th gear upwards and about 3500rpm and the last time I researched and enquirer about this I was told its the boost level reaching max allowed boost so is bled off by the diverter to maintain the requested boost level.
    Noticeable on the k04 car as the diverter blends this pressure in to the intake system which is heard with an intake fitted, this noise is usually almost silent on stock engine cover.
    This is the same as anything else once you hear it once you tune in to that noise and notice it all the time even if its done it for months unheard.
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  17. mechanic69
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    mechanic69 Active Member

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    [Jun 25, 2014]
    I'll check tomorrow but I'm not sure the gear matters so much, more how many beans your giving it, sure I get it in multiple gears
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  18. Marshy
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    Marshy Active Member

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    [Jun 25, 2014]
    From memory I can only get it in 4th upwards when the engine load allows the boost level to reach specified target
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  19. Rick @ Unicorn Motor Dev.
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    Rick @ Unicorn Motor Dev. Site Sponsor Site Sponsor

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    [Jun 26, 2014]
    "too much air" is actually correct. Or more correctly the engine cannot flow enough air for a given pressure. The turbo can only flow what the engine is flowing and this flow level is on the surge line if the turbo.

    Rick
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  20. mechanic69
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    mechanic69 Active Member

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    [Jun 26, 2014]
    Your right Marshy 4th gear and up
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  21. mechanic69
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    mechanic69 Active Member

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    [Jun 26, 2014]
    OK so the restriction is the engine /exhaust, the turbo pushes what it can in and the CAI supplies the air required by the turbo?
    #20
  22. Gaz-M
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    Gaz-M Member

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    [Jun 26, 2014]
    No the engine and exhaust can flow much more than the K04 could produce, but at a certain given time the turbo can be producing more boost pressure than the engine needs- and vents the excess boost off via the diverter valve, im presuming thats what Rick means although the wastegate is what really should be controlling the boost by diverting exhaust gasses away from the turbo to stop it continuing to build un-required pressure.
    #21
  23. KentKid
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    KentKid Active Member

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    [Jun 27, 2014]
    Hi there, this happens with my S3 too.

    I'm running Revo 2+ with an ITG Maxogen CAI.

    I was also concerned by the sound - that sounds like fluttering when you're flooring it - but was told that this is a standard feature of the setup I've got, and nothing to worry about...
    #22
  24. RedDejavu
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    RedDejavu Well-Known Member

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    [Jun 27, 2014]

    you should be worried that you need a bigger turbo :)
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