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funny boost

Discussion in 'A3/S3 Forum (8L Chassis)' started by malcolm30029085, Feb 24, 2010.

  1. malcolm30029085
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    malcolm30029085 Member

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    [Feb 24, 2010]
    having trouble with my boost, if my s3 is driven fast (foot flat to the floor through the gears ) the boost spikes right up 2 bout 14 psi and holds bout 10 ish. but if driven normaly ie on the motorway, and then i go to accelerate the boost struggles to build up and barely reaches 8-9psi.also as the boost gauge is climbing it seams to be fluxtuating up and down, could this be the dv not holding the pressure??
    its not had a re-map,also got new n75(j), and checked for leaks!!
    #1
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  3. Sandip
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    Sandip Well-Known Member

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    [Feb 24, 2010]
    What is the gauge been tapped into? Its sounds like you may have a leak somewhere
    #2
  4. sportstractor
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    sportstractor Chugger

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    [Feb 24, 2010]
    hmmm, i heard that N75 J's dont work for everybody??

    boost or vaccum leak possibly
    #3
  5. malcolm30029085
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    malcolm30029085 Member

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    [Feb 24, 2010]
    the boost gauge to pluged into the top of the dv, maybe i should try the standard n75, how can i test the dv??
    #4
  6. feville
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    feville Frank

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    [Feb 24, 2010]
    My friend had boost flux problems with his j valve, he adjusted the screw on the valve which sorted it (after some trial and error).

    He was boosting about 22psi/holding 20psi tho on mapped software.
    #5
  7. malcolm30029085
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    malcolm30029085 Member

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    [Feb 24, 2010]
    which screw is that??
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  8. feville
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    feville Frank

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    [Feb 24, 2010]
    On top of the valve there is a hole machined out to access a flat screw (T fitting on the bottom) this adjusts the valves internal spring tension. Pretty sure there are some threads out there on it, i haven't had any experiance myself but it could be worth a shot?
    #7
  9. Lemon S3
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    Lemon S3 Alex

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    [Feb 25, 2010]
    Also try changing where you plumbed your gauge into, don't think its 100% when using the dv vacuum pipe.
    T piece from the fuel regulator, I've never had a problem with it.
    #8

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