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Thread: NAG1/A580 Part Throttle Shift Scheduling Table Tuning

  1. #1
    Potential Tuner
    Join Date
    Nov 2019

    NAG1/A580 Part Throttle Shift Scheduling Table Tuning Questions

    Hi all,

    I have a Sprintex supercharged 2013 Jeep Wrangler with the NAG1 trans in which I'm wanting to tune the part throttle shifting on.
    From the PT tables the shifts are scheduled by the Accelerator Pedal Position vs Output Shaft Speed.
    In these tables what is the actual PID used for the Accelerator Pedal Position?

    I have data logged the following to try and determine the shifting behavior:

    Throttle & Accel PID's:
    Accelerator Pedal Position Sensor (V)
    Accelerator Position D (%)
    Commanded Throttle Actuator (%)
    Throttle Position (%)
    Trans Pedal Position (%)

    Trans PID's
    WOT Shift (Flag)
    Upshift (Flag)
    Downshift (Flag)
    Trans Current Gear
    Trans Shift Mode
    Aggression Blend(%)
    Upshift Speed Offset (RPM)
    Downshift Speed Offset (RPM)
    Trans Turbine RPM (RPM)
    Trans Output Shaft RPM (RPM)

    Upon reviewing data logs with very light throttle applications (quasi-steady state to eliminate any other transients) I cannot seem to link the commanded upshift/downshift (flag) and corresponding output shaft speed to any throttle PID. All of them seem to be way out re: 50+ RPMs . The aggression blend is 0.0% so one would assume that the normal scheduling table would be used. On the other hand, the WOT shift table is predictable and commands the shifts once the output shaft speed is reached.

    To add to the confusion, none of the 4 throttle % PIDs I've logged are the same value. Furthermore, the only PID that reaches 100% on WOT is the trans pedal position. I have confirmed that this PID triggers the WOT shift flag, however it comes no where near the values when a shift is commanded.

    What I think I know:
    The Accelerator Position D (%) is derived from the Accelerator Pedal Position Sensor (V) and maxes out at around 91%.
    The Commanded Throttle Actuator (%) follows the Throttle Position (%) but has a -10% offset... They max out at ~76% and 86% respectively (Which one is the actual throttle blade position??).
    The Trans Pedal Position (%) seems to follow the Accelerator Position D (%) however it is scaled from 0 - 100%. Least corresponding PID to the shift scheduling tables.

    Any help would be greatly appreciated.
    Kind regards,

    Tune and corresponding datalog attached.
    Attached Files Attached Files
    Last edited by HaasExp; 3 Weeks Ago at 02:27 AM.

  2. #2
    Potential Tuner
    Join Date
    Nov 2019
    I done a few more datalogs and have attached some screen captures. Again it seems something is not right with these PT shift schedule tables as the shifts are commanded at a much higher (logged) output shaft speed than what is requested in the table.

    For example, in the following log we have a light throttle, 1-2 shift.
    1-2 upShiftTrace.JPG
    The marker line is at the exact moment the upshift flag is triggered. In the log this occurs at an output shaft speed (OSS) is 658rpm and the maximum that any accel or throttle PIDs register at that time is ~22%. However, this shift should occur at an OSS speed of ~345rpm according to the normal shift table or ~885rpm according to the performance shift table.
    Is there still some blending going on between the performance and normal shift tables? The only transmission PID I could find and log the says anything about blends is the "aggression blend". it however stays at 0.0% when steady throttle is applied.

    The full datalog is attached. It also shows this odd behavior with other gears shifts.

    Im also still at a loss at to which PID is used as the "Accelerator Pedal Position" in these tables. The only PID that swings between 0-100% is the "Trans Pedal Position".
    A virtually identical question/issue about the PT shift scheduling on a 2013 JK wrangler was previously posted in this thread but very little info was gathered:

    Regards Dan

    Last edited by HaasExp; 3 Weeks Ago at 02:32 AM.

  3. #3
    Advanced Tuner
    Join Date
    Nov 2017
    I'm not familiar with the Nag1 tables.

    Is shift ID loggable? It could be that there is another table somewhere it is referencing.

    What happens if you change the table some? Do shifts follow your change at least somewhat? Or are your changes ineffective?

  4. #4
    Turn the Performance Driving Factor switch to disable.

    Or try taking it out of 4WD.

    4WD may make it reverence the Performance shift tables.

    Then just tune the Normal shift tables. Or make both the Normal and Performance part throttle tables the same.

    In your logs the shifts are basically what the Performance part throttle tables are set too.
    Last edited by Moparmatty; 3 Weeks Ago at 10:42 AM.
    2006 Chrysler 300C SRT-8
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  5. #5
    Potential Tuner
    Join Date
    Nov 2019
    Thanks for the replies so far guys.

    The only PID that comes close to a shift ID is the "Trans Shift Mode" which always has the value of "4WD" in the case of the Jeep wrangler. The only reference to this shift mode is in Torque Convertor -> TCC Pattern where this is set to "Normal" for the 4WD shift mode.

    I haven't played with the tables yet as I cannot predict their behavior, but I shall try disabling the "Performance Driving Factor" switch and make both the Normal and Performance part time shift tables the same to try and get some predictable PT shift characteristics as per Moparmatty's suggestion.

    I guess I should again just start with what should be the most simplest question: What is the actual PID used for the "Accelerator Pedal Position (%)" in these PT shift tables? All these tables are referenced to 0-100% Accelerator Pedal Position, even in stock guise and the only PID I've observed that swings 0-100% is the "Trans Pedal Position (%)" as previously stated. Is this the correct PID?


  6. #6
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    Join Date
    Nov 2019
    So I think I may have made a bit of progress trying to figure out this PT shifting behaviour.
    I've disabled the "Performance Driving Factor" switch and have mimicked the values from the Normal PT shift tables into the Performance PT shift tables.

    In the latest data log I've noticed that the shifts are scheduled very close to the desired "Trans Output Shaft RPM" when the "Upshift Speed Offset" = 0rpm.
    As shown in the following capture, the 3-4 shift is scheduled at a trans output shaft speed of 952rpm at a corresponding trans pedal position of 4%. This is pretty much a match to the desired 950rpm at 0% pedal position requested in the table.

    Thus it seems that this "Upshift Speed Offset" PID is an adder to the OSS values in the PT tables. Im led to believe that the "Upshift Speed Offset" is determined by the "Driving Factor", which is calculated through the "Term Coefficients" and "Decay Divisors".
    Can anyone confirm this or know the actual relationship between all these variables?
    Is it also possible to log this "Driving Factor"?


  7. #7
    Potential Tuner
    Join Date
    Nov 2019
    Scrap the idea of the trans shifting at the desired Accel Pedal/OSS when the upshift/downshift offset speed is 0.
    Shown in the following log is a 1-2 & a 2-3 shift where the OSS = 0rpm.

    Here the 1-2 shift occurs at an OSS of 628rpm. This would coincide with an accelerator pedal between 60 - 80% from the PT shift schedule tables. However, as you can see, there are no accel pedal PIDs anywhere near this value.
    In similar fashion the 2-3 shift occurs at an OSS of 893rpm which coincides with a pedal value between 40 - 60% from the tables.

    What is actually going on here?? Im beginning to believe there must be a bug or a parameter missing in the scanner/editor. The PT shift behaviour simply cannot be explained unless I'm completely missing something here.

    Any help would be greatly appreciated.
    Attached Files Attached Files

  8. #8
    have you made any more progress on this? I have a 16 jeep wrangler that's doing the same thing. it has an sps supercharger on it and im struggling with pt shifting from 3-4 it will rev up to 3k and will stay there until I release the pedal. when I'm commanding it to shift at way lower rpms. I made a calculator on excel to translate oss to engine rpm and to mph and it still does whatever it wants. its running the egs53 controller on a a580 transmission. customer is from out of town and came here from another shop that didn't do too much of a job tuning it and I'm stuck cleaning up the trans tune and engine tune.
    2017 mustang gt

  9. #9
    Potential Tuner
    Join Date
    Nov 2019
    Hi Tadias48,

    Glad to hear I'm not alone. There are also a few other threads on this forum of others having issues with the NAG1 part throttle shift tuning on their Jeep Wranglers. While most upshifts occur at reasonable engine speeds (but still dont follow the pt shift tables) the 3-4 shift is is by far the worst. If around 25% throttle is applied, mine will hold 3rd seemingly forever and will not command an upshift until the pedal is released. This was the main reason I purchased HP tuners in the first place.

    Its almost like the PT tables are not even being used and some other table(s)/parameter(s) that haven't been mapped out are determining the shift.

    Im not sure if this is only related to the NAG1 in the Jeep wrangler platform. I was hoping that some of the Dodge tuners could chime in here to see if this issue extends to other vehicles.

    Unless I'm missing something really simple, it seems like we cannot predictably tune the NAG1 part throttle shifting behavior in these Wranglers through HP tuners.

    What is the best point of contact through HP tuners to try and get this issue resolved?