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Thread: "Steady MAP", "Delta CylAir" or custom PIDs that span frames?

  1. #1
    Senior Tuner
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    "Steady MAP", "Delta CylAir" or custom PIDs that span frames?

    I would like to be able to better filter the histograms
    (WB AFR) to discard all transient data, which only
    adds garbage to the mix. I would like to punt anything
    that comes from a frame that hasn't had steady MAP
    for at least two prior (maybe +/- 10%).

    I know the PCM makes "steady MAP" decisions for MAF
    vs Dynamic Airflow, and know there is a delta-CylAir
    calc for burst knock, but haven't found either of these
    as selectable PIDs.

    Alternatively, if custom PIDs could refer to previous
    frame data (to do a MAP(now)-MAP(last) calculation)
    that would be similarly useful. Just want to do some
    sort of time-domain discrimination rather than praying
    the averaging will clean up the garbage (it seems to
    not, at least not reliably; that would need an equal
    population-weight of garbage-high and garbage-low,
    which is not all that likely and more to the point,
    not knowable. Well, I guess there is Excel postprocessing
    (if I was any kind of Excel whiz). But then you're gone
    from histogram and special paste land.

  2. #2
    SeƱor Tuner MeentSS02's Avatar
    Join Date
    Jun 2005
    Location
    Dayton, OH
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    1,132
    Agreed - I've done some Excel post processing, but would like it to be automated so I can keep it in histogram land. I've had some luck with just looking at standard deviation and throwing out the outliers, and then filtering by whatever caused it to be an outlier (like a dropped frame that reads my AFR at 9.5).