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Tech Question - Boost

Discussion in 'A4/A4 cabriolet/S4 forum(B6 chassis)' started by A4Andy, Aug 4, 2007.

  1. A4Andy
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    A4Andy Quattro-tastic. Not half.

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    [Aug 4, 2007]
    If I'm showing a steady 15PSI at the manifold via a boost gauge, where the ******* can my boost be leaking from?! When I accelerate while in turbo country, above 2.2k or whatever, I get a sound like an air compressor blowing; I mean it's ******* loud.

    Along with this comes retardation of performance, the car isn't anywhere near as rapid as it should be having been mapped. Forge 007 fitted 10K ago as well.

    So, before I trade her to some salesman that deserves all the misery that I can bestow up him, do anyone have any last ditch ideas?
    #1
  2. golf
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    golf ***** rent boy VCDS Map User

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    [Aug 4, 2007]
    What engine have you got?
    #2
  3. J7USS
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    J7USS Shuddup Foooool!!

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    [Aug 4, 2007]
    Mine did this a while back, It sounded like a Hoover when I fling'd my foot down.

    Mine was the 6inch Vac pipe on top of the engine. Ill get some pics up to show you when I can take a shot

    Also I noticed my Main turbo pipe that runs into it was very loose when I checked.
    #3
  4. A4Andy
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    A4Andy Quattro-tastic. Not half.

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    [Aug 4, 2007]
    1.8T, 150 standard. Revo'd.

    J7uss, did you lose performance?
    #4
  5. james0808
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    james0808 Active Member

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    [Aug 4, 2007]
    You will need to check all your boost pipes,big intercooler ones and the vacuum ones for loose connections or splits.
    Check your diverter valve first though.
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  6. A4Andy
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    A4Andy Quattro-tastic. Not half.

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    [Aug 4, 2007]
    It's showing 15 PSI at the manifold, after peaking at 18 PSI. The pressure is steady. After the manifold it's straight into the cylinders is it not?

    So where can it be escaping?
    #6
  7. dualmono21
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    dualmono21 Well-Known Member VCDS Map User

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    [Aug 4, 2007]
    a small leak would not be noticeable with your hearing
    if its a big leak and its loud then id check the large pipes
    especially the large one entering the turbo itself from the maf sensor
    after this check the intercooler pipes make sure there tight and no spilts in them
    #7
  8. A4Andy
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    A4Andy Quattro-tastic. Not half.

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    [Aug 4, 2007]
    All big pipes have been checked. Full boost is getting to the manifold...
    #8
  9. J7USS
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    J7USS Shuddup Foooool!!

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    [Aug 4, 2007]
    Yes I lost performance big style. I only found mine by chance.
    It sounds similar to mine, Il try and get pics once I get away from work.
    #9
  10. Elberoth
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    Elberoth Member

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    [Aug 5, 2007]
    Get someone with Vag-Com to check the Block 032 values. That will tell you if there is a boost leak or not.
    #10
  11. A4Andy
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    A4Andy Quattro-tastic. Not half.

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    [Aug 6, 2007]
    Top tip, cheers.

    What I don't understand is where it can be going. If full boost is available and showing at the manifold, where can it be escaping? Surely it goes straight from the manifold into the cylinder?
    #11
  12. claudefrog
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    claudefrog Member

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    [Aug 6, 2007]
    the turbo is just working a lot harder to supply the correct amount of boost.. I would get checking all hoses before driving too much harder, you will end up wrecking your turbo
    #12
  13. A4Andy
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    A4Andy Quattro-tastic. Not half.

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    [Aug 6, 2007]
    There

    Are

    No

    Leaking

    Pipes.
    #13
  14. golf
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    golf ***** rent boy VCDS Map User

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    [Aug 6, 2007]
    I wouldn't be so sure, Andy.
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  15. A4Andy
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    A4Andy Quattro-tastic. Not half.

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    [Aug 6, 2007]
    If pressure is steady at 15 PSI, what pipes exist between the manifold and the cyclinders? :meeting:
    #15
  16. james0808
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    james0808 Active Member

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    [Aug 6, 2007]
    There isnt any,i think what people are saying is,have you measured boost at the turbo to make sure its not producing say 18 psi and your leaking 3 psi before it gets to the manifold.
    #16
  17. A4Andy
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    A4Andy Quattro-tastic. Not half.

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    [Aug 6, 2007]
    No, the turbo should be producing 15 PSI, peaking at 18 PSI. Also, if there was a leak before the manifold the preasure wouldn't be constant, it would fluctuated, the gauge is solid on 15.
    #17
  18. Rev-head
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    Rev-head Active Member

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    [Aug 6, 2007]
    PM sent
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