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Audi S3 boost problems

Discussion in 'A3/S3 Forum (8L Chassis)' started by goodbuzzman1, Mar 24, 2014.

  1. goodbuzzman1
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    goodbuzzman1 Member

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    [Mar 24, 2014]
    When i picked up my s3 a few weeks ago i knew it would need a bit of work. ive sorted most of the problems but one remains.

    The boost seems to be a bit intermittent.

    so far i have checked for boost leaks. i found that there were leaks in a few breather pipes and also a small leak in the turbo intake pipe.

    I replaced all the offending pipes with nice new silicone ones at the weekend but there till seems to be random hesitance when i put the foot down. sometimes it pulls like a train and other times it stutters and then boosts.

    When i was replacing the TIP, i did notice a slight bit of play in the turbo left to right.

    Ive also been doing a bit of reading about the N75 valve so this evening i unplugged it and went for a spin.

    I have to say, the car felt like it had only 120hp but it was absolutely smooth all through every gear.

    does this mean the valve is good or bad :)

    ANy help on what to do next would be much appreciated

    cheers
    #1
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  3. Vex182
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    Vex182 Guess what I drive...

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    [Mar 24, 2014]
    Have you also checked the DV is working as it should? A good idea to check for any fault codes too
    #2
  4. russwuss
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    russwuss Active Member

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    [Mar 24, 2014]
    If you unplug the N75 you'll be boosting to around 6psi.. Hence why it feels about 120bhp - I'd try swapping the N75 and see if it makes a difference. Was the first thing I had to replace on my S3.
    #3
  5. russwuss
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    russwuss Active Member

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    [Mar 24, 2014]
    http://bit.ly/1ivqPVG

    ^ that's the one you want, they are more expensive from Audi if
    I remember correctly..
    #4
  6. goodbuzzman1
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    goodbuzzman1 Member

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    [Mar 25, 2014]
    how exactly would i go about testing it
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  7. goodbuzzman1
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    goodbuzzman1 Member

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    [Mar 25, 2014]

    do you think its worth replacing? i might just get one anyway and try it.
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  8. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Mar 25, 2014]
    Have you scanned for fault codes yet?

    <tuffty/>
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  9. goodbuzzman1
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    goodbuzzman1 Member

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    [Mar 25, 2014]
    I will be giving it a scan this evening. I just wanted to repair the obvious boost leaks before i did
    #8
  10. goodbuzzman1
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    goodbuzzman1 Member

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    [Mar 27, 2014]
    Ok. So i scanned the car this evening and it didnt give me any fault codes (apart from one for the radio antenna)

    I tested the diverter valve and that seems to be ok.

    What i did notice was that the pipe that goes from the diverter pipe over to the turbo pipe is suffering from the same heat related collapsing as all the other ones i have just replaced. One of the bends is especially bad and i cant imagine much can flow through it. but how much affect could it have? enough to affect performance?
    #9

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