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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

    Gaz-M Member

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    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.
     
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  3. wuta3

    wuta3 Well-Known Member

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    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.
     
  4. batch

    batch Active Member
    Team Glacier quattro Audi S3

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    Fairly normal on these mate, my Neuspeed CAI does it with Shark stage 1
     
  5. Aqualea90

    Aqualea90 New Member

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    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.
     
  6. Gaz-M

    Gaz-M Member

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    Cheers, just weird that my Mk5 Golf never done it!
     
  7. mechanic69

    mechanic69 Well-Known Member

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    My REVO does the same, sounds good mate!!!
     
  8. Gaz-M

    Gaz-M Member

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    Sounds wrong though, sounds like its dumping boost which isnt what you want on full throttle!
     
  9. Marshy

    Marshy Settled in
    Audi S3 Audi RS3

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    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.
     
  10. Aqualea90

    Aqualea90 New Member

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    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?
     
  11. mechanic69

    mechanic69 Well-Known Member

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    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
     
  12. S3_Mat

    S3_Mat Active Member

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    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

    S3Alex Rarely neutral
    Audi S3

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    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.
     
  14. RedDejavu

    RedDejavu Well-Known Member

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    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.
     
  15. mechanic69

    mechanic69 Well-Known Member

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    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.
     
  16. Marshy

    Marshy Settled in
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    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.
     
  17. mechanic69

    mechanic69 Well-Known Member

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    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
     
  18. Marshy

    Marshy Settled in
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    From memory I can only get it in 4th upwards when the engine load allows the boost level to reach specified target
     
  19. Rick @ Unicorn Motor Dev.

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    "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
     
  20. mechanic69

    mechanic69 Well-Known Member

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    Your right Marshy 4th gear and up
     
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  21. mechanic69

    mechanic69 Well-Known Member

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    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?
     
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  23. Gaz-M

    Gaz-M Member

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    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.
     
  24. KentKid

    KentKid Active Member

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    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...
     
  25. RedDejavu

    RedDejavu Well-Known Member

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