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DiabloSport Predator
Parameters Explained GM Predator









GM Predator parameters explained

We dedicated this page to explain the different parameters that the Predator allows the end user to adjust.
Please note that all parameters listed may not be available on all part numbers.


  • Torque Management
  • Injector Slope
  • Spark Adjustment
  • COT Protection
  • Cooling fan adjustment on new LS2/LS4/LS7 and 2007 Truck & SUV's
  • Tire size adjustment

    Torque Management

    PLEASE NOTE: Disabling torque management will put greater stress on your drive line.
    • TM Abuse Mode time limit:
      This is the time in abuse mode as a function of temperature. Turning it off in conjunction with Upshift Torque reduction and %Torque Reduction vs RPM will eliminate torque management.
    • %Torque Reduction vs RPM:
      Torque reduction as a function of RPM, turning it off in conjunction with TM abuse mode time limit and upshift torque reduction will eliminate torque management.
    • Upshift Torque reduction:
      Torque reduction control for each individual gear, turning it off in conjunction with TM abuse mode time limit and %Torque Reduction vs RPM will eliminate torque management. However we have noticed that the shift feel when disabling the upshift torque reduction in trucks and SUV's is reduced and therefore recommend leaving it ON for trucks and SUV's.

    Injector Slope

      Use to determine the injector size and also to correct the long term fuel trims.
    • Injector change:
      To properly set up injector size it is recommended that you multiply the current slope by injector % change.
      Example: #24 to #30 (30-24) / 24 * 100 = 25% so multiply the entire slope by 25% to get you in the ballpark.
    • Determining long term fuel trims:
      Long term fuel trims are an accumulated value of fuel added or subtracted during closed loop operation.
      To verify and tune for long term fuel trims, drive the vehicle for 30 minutes or until warmed up, monitor long term fuel trims and get an average value. The easiest way to do this is to get on the highway, enable cruise control and sit at 55mph while monitoring the data. Ideal values should be in the 0 to negative 2 range.
      Once you get the average long term fuel trim value:
      Positive long term fuel trims For a positive value you subtract that value in percent in the predator injector slope. It is also recommended to lean both fuel tables by the same percentage.
      Negative long term fuel trims For a negative value you add that value in percent in the predator injector slope. It is also recommended to richen both fuel tables by that same percentage.
      Once adjustment is done and tune installed, take the vehicle out and verify the long term fuel trims per previously described method. Adjust again if necessary.

    Spark Adjustment
      To properly dial in your timing using the Predator you need to log or monitor the following live data parameters.
      Spark, this is your actual timing (in degrees) at any given time.
      Knock Retard, this the amount of timing removed (in degrees) due to knock (detonation/ping). The knock sensors can in rare cases pick up other harsh engine noises as well, if this is the case it is recommended to fix the cause of the noise before proceeding.
      You basically always want the knock retard to read zero under wide open throttle conditions, it is normal for it to show some KR when stomping on the throttle and also during the shift.
      Monitor the spark and the knock retard pids under wide open throttle and see if you have any knock retard, anything higher than 1 should be adjusted in the respective timing range in the Predator , if the knock is severe, 5 deg plus, try lowering spark by 10%, if less than 5 deg, try 5%. Make another wide open pass and monitor the same pids and basically keep doing this until you seen no knock retard.
      NOTE: The use of respective grade fuel should be used with tune choice.
      The 87 octane tune will run fine on 87, 89, 91 and 93 octane. 91 octane tune will run on 87,89 and 91 octane. The 93 octane (Performance) tune will run on 91 and 93 octane. If severe knock cannot be remedied by adjusting the parameters for it, try to install the factory tune and monitor the knock using it. If knock still is present consider switching fuel brand.
      DiabloSport recommends using fuels from the following vendors:
      Mobil, Sunoco and Amoco/BP.

    COT Protection

    Catalytic Overtemp Protection (COT) is used to add fuel to cool down the catalytic converters and it should be disabled only when cats are removed.
    For off-road use only!
    • COT enable temp:
      temperature when to enable the COT process, set this high(1200) to disable it.


    Cooling fan adjustment on new LS2/LS4/LS7 and 2007 Truck & SUV's

    These newer GM calibrations no longer have fan on/off temps like the older LS1 based calibrations.
    The fans now run on a variable speed controller which the pcm controls, so we set the Predator parameter up to allow individual adjustments per temperature cell in the actual calibration.
    The value adjusted is the desired % of power to run the fan at that specific temperature, where 0 is the lowest and 99.99 is the highest.

    Tire size adjustment

    The Predator has two different ways to adjust for tire size.
    First Method
    Enter your original tire size then enter the new(actual) tire size.
    The Predator will prompt you to put in your original tire size in metric format (ex. 265/75-17), once entered the Predator will then display your entry and you confirm it by pressing enter.
    The Predator will then promt you to put in the new (actual) tire size in metric format (ex.305/50-22), once entered the Predator will then display your entry and you confirm it by pressing enter.
    You can now press esc to go back to the main modify parameter menu and if no more adjustments are desired press esc again and you will be asked to install modified tune, press yes and let Predator upload new adjusted tune to your vehicle.
    To reset the tire size, you can go to reset parameters and then reinstall the tune.
    Second Method
    Enter the tire size or the overall tire height
    The Predator will ask if you want to adjust it via entering the tire size or by the actual tire height.
    Tire size, enter the metric tire size displayed on the side wall of the tire (ex.265/75-17) then press enter to confirm.
    You can now press esc to go back to the main modify parameter menu and if no more adjustments are desired press esc again and you will be asked to install modified tune, press yes and let Predator upload new adjusted tune to your vehicle.
    Tire height, measure the tire height using a tape measure and enter that measurement in the Predator, then press enter to confirm.
    You can now press esc to go back to the main modify parameter menu and if no more adjustments are desired press esc again and you will be asked to install modified tune, press yes and let Predator upload new adjusted tune to your vehicle.
    To reset the tire size, you can go to reset parameters and then reinstall the tune.

    • Predator Custom Tuning
    Custom tunes are most likely needed if you modified your car, which are available from any CMR dealer.

    Click here to find a CMR dealer in your area.

    The Predator can hold up to 5 custom tunes made by any CMR dealer nationwide, the upload process is less than 30sec. This makes the predator a valuable product to have. If you tuned your vehicle from stock and like the power your car is producing, most likely you will start adding modifications to your car as time goes on. Good thing you have a predator because u can go to any of our CMR dealers and get a custom tune for your exact modification setup. Your car will run better, faster and get the best gas mileage that can be achieved for that particular modification setup.

    Many of your custom tuning questions involving DiabloSport products, they may already be answered in the FAQ section of our website. If not you can post questions and get the answers in 24 hours. Please refer to FAQ or for all your custom dyno tuning needs please refer to our dealer locator to find the
    CMR tuning dealer near you.


    DiabloSport products are not intended for sale or use in the state of California on emission regulated vehicles.
    DiabloSport diesel products are not intended for use in emission controlled vehicles and are manufactured specifically for racing vehicles.
    While the majority of DiabloSport products will give you the option to adjust your speed limiter, this adjustability is intended for race use only.