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Thread: Spark Advance table changes when saved in Tunerpro

  1. #1
    Fuel Injected!
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    Spark Advance table changes when saved in Tunerpro

    If I load a new spark advance table and save it, when I open the table again some of the values are slightly changed.
    Using Advanced $0D TP5 v251.xdf

    Example using Vortec spark table, 400 RPM row.

    Original values pasted into spark table
    23.0 23.0 23.0 23.0 23.0 21.0 18.0 14.0 12.0 11.0 9.0 7.0 5.0 2.0 .0 -1.0 -2.0

    Values in Tunerpro after saving table, and opening it again
    22.9 22.9 22.9 22.9 22.9 21.1 17.9 14.1 12.0 10.9 9.1 7.0 4.9 2.1 .0 -1.1 -2.1

    Any insight would be appreciated.
    Thanks

  2. #2
    Fuel Injected! brian617's Avatar
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    It does that automatically, not all the numbers can be whole numbers. Why, i'm not sure?
    89 K1500 Scottsdale 5.7L 5spd 3:42 RamJet cam Dart iron TBI heads 427 PCM swap
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  3. #3
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    required due to the way the math works. i assume 0D uses the normal X = 90/255 conversion? if so, the values in-table are rounded to their nearest whole 8-bit value. in this case, there is a resolution of .35*, so it gets rounded up or down accordingly.

    entirely normal.
    1995 Chevrolet Monte Carlo LS 3100 + 4T60E


  4. #4
    LT1 specialist steveo's Avatar
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    it's weird to me that tunerpro doesnt' snap to the nearest useable value when making any adjustment. when i write software, it only allows input to match output capabilities.

    i've gotten used to it, though. after i make some changes, i just close and open the table to see where it rounds, just out of habit. and maybe you should too.

    im simple terms, what you have to realize is that an 8 bit value is 0-255, so there's only 256 possible values. what you're seeing is just some math to make the raw hex displayed in a way that's in a unit of measure you'll understand.

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