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Boost pressure and airflow query

Discussion in 'A3/S3 Forum (8L Chassis)' started by gez, Dec 13, 2012.

  1. gez

    gez S3 hunter

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    Logged my airflow using a snapon solus pro to get a rough idea on power.
    seeing 187gs on full throttle 3rd gear. Am i right to guess it equates to 260hp?
    Also logged 2490 mbar of boost which equates to 2.4 bar boost pressure?!?!?

    Bam engine
    revo2, v3manifold, 3"downpipe and 120cell cat, ahfab fmic, B5 v3 intake, std airbox with pipercross filter and 4"cold feed

    Is it about right or is my airflow metre getting old and reading poor?
     
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  3. Yohan87

    Yohan87 Member

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    Not quite.

    Your MAP sensor won't read higher than 2.5BAR, plus you have to subtract atmospheric pressure from that, approximately 1000mbar. You're not making 33psi lol.

    I'd expect more power from the mods you have described.

    What fuel are you on?
     
  4. gez

    gez S3 hunter

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    Only on regular unleaded as shell had run out of v-power last night. Would that make "much" difference?
    with these mods what airflow reading should i expect?
     
  5. badger5

    badger5 www.badger5.co.uk
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    look at cf 020 for what your engine thinks of the fuel for that boost AND log lambda 031
     
  6. Prawn

    Prawn My other car is a MINI!!!!

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    2490mb logged is around 1490mb of boost, so call it 1.5 bar, 22psi.

    g/s - bhp conversion is /0.8, so 187g/s implies around 234bhp.

    Typical st1 BAM would expect around 200g/s, many with your sort of spec are seeing 220g/s+.

    that's not to say that MAF figures should be taken as gospel, but it's certainly a very low reading compared to those typically seen with your level of hardware.
     
  7. gez

    gez S3 hunter

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    Ok bill will log them tomorrow and see.
    car pulls very well and doubt its making 230bhp. Is it more likely that my air flow sensor is playing up?
    spose getting it on the rollers for a true reading is the best idea
     
  8. Vex182

    Vex182 Guess what I drive...

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    I had a run in mine earlier and got 231g at the MAF (288bhp!?) so m MAF will be working but no way is it running that much power. I would have thought hours would be high like mine too with your spec and this cold weather. That was 4th and WOT.
     

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