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Overboost in high gears??

Discussion in 'Leon Mk1 (2000-2006)' started by Tessitura, Feb 11, 2017.

  1. Tessitura

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    Hi guys

    So, standard map AMK cupra R, should be about 0.7bar roughly.

    between 1st-4th gear it holds about 0.7 on the gauge.

    but in 5th, 40mph, foot down, it boost to over 1bar and continues boosting unless i let off.

    Initial thoughts are either the Wastegate actuator or n75?

    Car is standard mapped, but has miltek catback, sfs oversize pipe, forge 008, done the usual n249 delete etc. and pcv simplification.

    any ideas??

    /josh
     
  2. mty12345

    mty12345 Active Member

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    40mph is a pretty low speed for it to accelerate from in 5th gear.

    Maybe it's possible that the ECU allows a slight overboost to try and deliver the acceleration you're demanding??

    What happens if you accelerate from 60mph in 5th? Does it still spike?
     
    #2 mty12345, Feb 11, 2017
    Last edited: Feb 11, 2017
  3. Hedgehog Dodger

    Hedgehog Dodger Active Member

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    5th gear 40mph......thats labouring speed.

    It shouldnt overboost straight away at 40mph in 5th as your only on 2k revs.

    What is the exact rpm when you.hit 1bar in 5th?
     
  4. Tessitura

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    Not high revs, so if you sit at 40mph off boost in 5th gear, then floor it the boost gauge shoots over 1bar.
     
  5. 19jeff89

    19jeff89 Active Member

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    is the n249 valve what compensates this by releasing pressure through the diverter valve?
     
  6. mty12345

    mty12345 Active Member

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    Nope, the N249 only works when you lift off the throttle, not at any other time. It simply opens the diverter valve a fraction of a second sooner than it would do on it own. This stops stress and the turbo and stops the turbo stalling as it would without the N249.
     
    #6 mty12345, Feb 13, 2017
    Last edited: Feb 13, 2017
  7. 19jeff89

    19jeff89 Active Member

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    i see didnt know if it did other things with it being electrically controlled which is why i didnt delete it, i leave as is seems fine with it
     
  8. mty12345

    mty12345 Active Member

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    No that's it's only function mate. I've still got mine too....it's there for a reason :)
     
  9. Tessitura

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    ive done a little reading and boost creep and be caused by the wastegate not allowing enough air to pass by the turbo. i can only imagine the WG isnt opening enough for some reason.

    thinking sticky WGA
     

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