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Advice Required - Vag Com Log

Discussion in 'A3/S3 Forum (8L Chassis)' started by sideways steve, Jan 30, 2012.

  1. sideways steve
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    sideways steve Member

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    [Jan 30, 2012]
    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.
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  3. sideways steve
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    sideways steve Member

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  4. sideways steve
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    sideways steve Member

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    [Jan 30, 2012]
    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 ?
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  5. StaceyS3
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    StaceyS3 Well-Known Member

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    [Jan 30, 2012]
    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 ;)
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  6. sideways steve
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    sideways steve Member

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    [Jan 30, 2012]
    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
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  7. badger5
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    badger5 www.badger5.co.uk Site Sponsor

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    [Jan 31, 2012]
    requested boost is'nt being met... close but not getting quote there.
    check for usual leaks
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  8. sideways steve
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    sideways steve Member

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    [Jan 31, 2012]
    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 ?
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  9. badger5
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    badger5 www.badger5.co.uk Site Sponsor

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    [Jan 31, 2012]
    actuator test is disconnect n75 electrically and go see what boost it holds.. Typically 5psi rising to 8psi on some as a guide
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  10. sideways steve
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    sideways steve Member

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    [Feb 1, 2012]
    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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