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OBD Throttle position not reaching 100%

loggyboyloggyboy
edited February 2014 in RaceChrono for Android
Is there anyway to adjust or tweak what RC reads as 100% throttle? When full throttle in my Clio 172, it only registers is 66%. Or is this likely to be down to the bluetooth reader, (or the car itself) - and not RC's interpretation of the data its recieving.

Comments

  • aol_of_RaceChronoaol_of_RaceChrono
    edited February 2014
    I'm sure it is actually the car reporting 66%. The catch is that there is several throttle position channels in OBD-II protocol:

    Throttle Position
    Absolute throttle position B
    Absolute throttle position C
    Accelerator pedal position D
    Accelerator pedal position E
    Accelerator pedal position F

    Most likely one of these will report correct range for your car. For my BMW I have to pick Accelerator pedal position D. For my Audi I need to use the Throttle Position.
  • loggyboyloggyboy
    I did try that, I selected them before the session was started, but when the session started they did not appear. So I went in to settings during the session and additional options you list above were not shown.
    I will try again though.
  • aol_of_RaceChronoaol_of_RaceChrono
    edited February 2014
    If they are not shown during session, they are not supported by your car. Then the car just reports 66% for full throttle. Don't know why.
  • mikelgaldakaomikelgaldakao
    My suggestion:
    In dashware: Create dynamic bar component with min 0 and max 66.
    In racerender: Configure existing throttle bar and set range to 0-66

    It works well for my and it's better than modify the csv.

    Other alternative in both programs is the next:
    Create calculated values. AcelPos=throttle /66
    Sorry for my bad English, I want help!
  • aol_of_RaceChronoaol_of_RaceChrono
    edited April 2015
    RaceChrono Pro does this internally for it's own videos, but for .CSV exporting it's not done. After all these are the raw values recorded from the car.
  • sti04sti04
    edited April 2015
    My range is about 15% to 81%, seems strange but that is what OBD reports so as mikelgaldakao mentioned, just set the ranges in which ever application you're using. Go for a random drive logging all of the available throttle channels and work out which is the best one to use and min/max values.
  • aol_of_RaceChronoaol_of_RaceChrono
    edited April 2015
    It's 20% to 80% on the M235 Racing Cup too. I guess it's pretty normal thing. On RaceChrono Pro you can check the "scaled" checkbox on the overlay settings on that gauge. The CSV and VBO exports are raw, but there might be an option to scale it on the whichever video generator software you're using.
  • timurrrrtimurrrr
    edited July 2020
    Sorry to revive this old thread, but just as another data point, it seems that Subaru BRZ/Toyota 86/Scion FR-S ECUs are reporting "Relative accelerator position" incorrectly. I wonder if a similar problem exists for other ECUs.

    I recorded a session in my Subaru BRZ where I was flooring the accelerator on multiple occasions, but each time the values displayed in RaceChrono were around 40%...41%. Then I realized that 100/255 ~=0.39 and it started to make sense.
    According to Wikipedia [1], for Mode 01 PID 5A a 100*A/255 formula should be used.

    However, when I created a custom PID 0x015A and watched "Live data" while pressing and releasing the accelerator pedal, I saw the values going from 0x0 to 0x67..0x6D (103...109) on my car.
    Using a custom Equation "min(A, 100)" seems to give me the 0–100% values that make a lot more sense.

    I wonder if this workaround can be built into RaceChrono for the affected cars?

    [1] https://en.wikipedia.org/wiki/OBD-II_PIDs#Service_01
  • aol_of_RaceChronoaol_of_RaceChrono
    edited July 2020
    @timurrrr It's normal for this PID not to report 0-100% (values 0-255). But it differs from vehicle to vehicle so it cannot really be modified like you propose. While it would fix it for you, it would not fix it for most people. RaceChrono has "scaled" option for gauges, that scales any range to 0-100%, but not for graphs etc. Creating own custom channel is a nice approach to fix it for your vehicle. Just do new custom PID with equation "((A - min) / (max - min)) * 100", where min is your minimum value and max is your maximum value.
  • timurrrrtimurrrr
    Got it, thanks for confirming!
  • timurrrrtimurrrr
    > Creating own custom channel is a nice approach to fix it for your vehicle.

    It would be appreciated if there was a shortcut to make a copy of a standard / other OBD-II channel, instead of copy-typing multiple values from one screen to another.
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