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Advice Required - Vag Com Log

sideways steve Jan 30, 2012

  1. sideways steve

    sideways steve Member

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    Evening folks, I finally got around to logging the S3 as I have been feeling that its not been performing as it should.

    No codes logged at all however I think this log looks a bit odd ? Im suspicious of the boost pressures requested and achieved as well as the airflow. Im calculating that its running around 189bhp ish so down on power ?

    Car is stock, stock map but does have 3" DP and sport cat.

    Let me know your thoughts please, does this log look ok to you ? I started the run in 3rd gear from 1000 rpm roughly and held it until the red line before shifting to 4th briefly then backing off.
     
  2. sideways steve

    sideways steve Member

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  3. sideways steve

    sideways steve Member

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    According to what I am seeing I'm making 0.9 bar of boost when idling ? that doesn't sound right to me, nor does 1.7 bar when on boost ? Airflow's look low too ?
     
  4. StaceyS3

    StaceyS3 Well-Known Member

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    It takes into account atmospheric pressure which is 1 bar +- a little bit depending on where you are so just subtract 1 bar to give you boost pressure ;)
     
  5. sideways steve

    sideways steve Member

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    I was going to say ! LOL so the VCDS log shows absolute pressure rather than gauge, that makes more sense however still doesn't explain my low airflow's
     
  6. badger5

    badger5 www.badger5.co.uk Site Sponsor

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    requested boost is'nt being met... close but not getting quote there.
    check for usual leaks
     
  7. sideways steve

    sideways steve Member

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    Hi Bill,

    Thanks for your input, I will get under there tonight when I get home and have a poke about. I assume by the usual leaks you mean all the vac pipes etc around the TIP ?

    I am also planning to buy one of your TIP kits in the near future but I want to get everything running as it should in stock trim before going down that route to ensure I get the most out of any mods I do.

    I assume if i resolve why the boost is not meeting the requested duty then I should see my airflow rise accordingly and find the missing 20bhp ?

    I have actually noticed a slight whistle when under boost which I always thought was the tinny downpipe but now I am suspicious that it may indeed be a leak around that area.

    Could it be a weak actuator or is it more likely to be a leak ? Does anyone have a log file they can post from a car known to be running well that I can take a look at ? On the VCDS log how close to the requested value will the actual get ? are we talking within a few psi or almost bang on ?
     
  8. badger5

    badger5 www.badger5.co.uk Site Sponsor

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    actuator test is disconnect n75 electrically and go see what boost it holds.. Typically 5psi rising to 8psi on some as a guide
     
  9. sideways steve

    sideways steve Member

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    Cheers,

    didnt get a chance to look last night but hopefully will get time either today or failing that it will be the weekend.

    Its just too cold outside lol !
     

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