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Thread: NTK AFRM gen2 to HP

  1. #1
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    NTK AFRM gen2 to HP

    trying to match logging output to HP tuners. does anyone know the function formula to read properly with NTK AFRM gen2? The closest match is AFR500 but still off.

  2. #2
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    I am using afr500 and chaged voltage to 9.5 instead of 9 and reading closer but still little off. If someone knows the correct imput please share

  3. #3
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    Best to figure out the actual formula, just arbitrarily changing the offset part of the formula isn't how you do it.

    Also MAKE SURE you have a good ground ran from the gauge to the HPT interface. People just using whatever ground is easiest (or none at all) see this kind of issue all the time.

    The manual for that gauge says:

    0.5V = AFR of 9.0
    4.5V = AFR of 20.00

    y=mx+b, going back to basic algebra here.

    So, figure out slope first

    (20 - 9) / (4.5 - 0.5) --> 2.75 AFR per volt

    Then figure out offset

    You know at 0.5V the AFR is 9.0, and you know slope, so plug in what you know

    9.0 = 2.75 * 0.5 + b
    9.0 = 1.375 + b
    b = 7.625

    So the right formula is 2.75 * voltage + 7.625

    Test to be sure

    2.75 * 4.5 + 7.625 --> AFR of 20 (checks out)
    2.75 * 0.5 + 7.625 --> AFR of 9 (checks out)

    So, try this formula. I inverted the 2.75 to match the format HPT wants.

    V / 0.3636 + 9
    Post a log and tune if you want help

    VCM Suite V3+ GETTING STARTED THREADS / HOW TO's

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    AlkyControl Meth, Monster LT1-S Twin, NT05R's
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  4. #4
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    Quote Originally Posted by schpenxel View Post
    Best to figure out the actual formula, just arbitrarily changing the offset part of the formula isn't how you do it.

    Also MAKE SURE you have a good ground ran from the gauge to the HPT interface. People just using whatever ground is easiest (or none at all) see this kind of issue all the time.

    The manual for that gauge says:

    0.5V = AFR of 9.0
    4.5V = AFR of 20.00

    y=mx+b, going back to basic algebra here.

    So, figure out slope first

    (20 - 9) / (4.5 - 0.5) --> 2.75 AFR per volt

    Then figure out offset

    You know at 0.5V the AFR is 9.0, and you know slope, so plug in what you know

    9.0 = 2.75 * 0.5 + b
    9.0 = 1.375 + b
    b = 7.625

    So the right formula is 2.75 * voltage + 7.625

    Test to be sure

    2.75 * 4.5 + 7.625 --> AFR of 20 (checks out)
    2.75 * 0.5 + 7.625 --> AFR of 9 (checks out)

    So, try this formula. I inverted the 2.75 to match the format HPT wants.

    V / 0.3636 + 9
    wow thanks. totally impressed. will surely try it. I was using the balanger afr 500 gen1 and changing to voltage to 9.4. seemed to provide the correct reading.
    cheers will report back

  5. #5
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    Changing the offset until you get one correct reading will only make it right in one spot.. the slope has to be right too or it will be further and further off the further you get from that one "right" value

  6. #6
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    Quote Originally Posted by schpenxel View Post
    Best to figure out the actual formula, just arbitrarily changing the offset part of the formula isn't how you do it.

    Also MAKE SURE you have a good ground ran from the gauge to the HPT interface. People just using whatever ground is easiest (or none at all) see this kind of issue all the time.

    The manual for that gauge says:

    0.5V = AFR of 9.0
    4.5V = AFR of 20.00

    y=mx+b, going back to basic algebra here.

    So, figure out slope first

    (20 - 9) / (4.5 - 0.5) --> 2.75 AFR per volt

    Then figure out offset

    You know at 0.5V the AFR is 9.0, and you know slope, so plug in what you know

    9.0 = 2.75 * 0.5 + b
    9.0 = 1.375 + b
    b = 7.625

    So the right formula is 2.75 * voltage + 7.625

    Test to be sure

    2.75 * 4.5 + 7.625 --> AFR of 20 (checks out)
    2.75 * 0.5 + 7.625 --> AFR of 9 (checks out)

    So, try this formula. I inverted the 2.75 to match the format HPT wants.

    V / 0.3636 + 9
    Sorry if this is a dumb question or if I am missing something in this math but I am setting up the same W/B tonight in my hp tuners.

    Why is the final formula V / .3636 + 9 ?

    According to the math should it not be
    V / .3636 + 7.625 ??

    Just trying to clarify before I put it in.

    Thanks for the help!

  7. #7
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    Looks like a typo on my part
    Post a log and tune if you want help

    VCM Suite V3+ GETTING STARTED THREADS / HOW TO's

    Tuner by night
    CPX Tuning
    2005 Corvette, M6
    ECS 1500 Supercharger
    AlkyControl Meth, Monster LT1-S Twin, NT05R's
    ID1000's, 220/240, .598/.598, 118 from Cam Motion

    2007 Escalade, A6
    Stock

  8. #8
    Thanks for this info and the explanation and yes
    V / .3636 + 7.625
    Is correct