Drew Technologies DASHDAQ-XL User Manual
Page 24
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Only three parameters are required for the calculation:
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Input Speed Signal: Choose Vehicle Speed from GenericOBD II or other Speed sensor input
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Input RPM Signal: Choose Engine RPM from GenericOBD II or other RPM sensor input
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Input Vehicle Weight (lbs): Enter the vehicle weight in pounds
The other parameters can usually be ignored, but you can try tuning the values for increased accuracy:
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Input Acceleration Filter Time:
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Input Accel Calc Type:
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Input Speed Filter Constant:
If you’ve assigned either statistic, to a gauge but you’re not seeing values, double-check that you’ve assigned signals for both the Input
Speed Signal and Input RPM Signal parameters. Also try assigning the input signals to a gauge to verify that DashDAQ is actually able to
get a reading.
The calculated values will be available under “Dyno Calculator” when you assign signals to a gauge.
FUEL ECONOMY CALCULATOR
DashDAQ can calculate instantaneous fuel economy and display the results by calculated Mass Air Flow, distance (miles per gallon) or by
time (gallons per hour).
Parameters for Economy Calculator
This calculator uses airflow to find the amount of fuel entering the motor. Vehicles with a Mass Air flow Sensor can measure airflow
directly. You only need to configure four parameters:
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Air Fuel Ratio: 14.7 for gasoline
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Fuel Density: 720 for gasoline
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Speed Signal: Vehicle Speed from GenericOBD II or other Speed input signal
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Mass Air Flow Signal: Air Flow Rate from MAF from GenericOBD II or other MAF input signal
If the vehicle does not have a Mass Airflow sensor, this driver provides a way to estimate MAF based on additional vehicle variables.
You additionally need to set:
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Mass Air Flow Signal: Calculated Mass Air flow from Economy Calculator
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Intake Air Temperature: Intake Air Temperature from GenericOBD II or other IAT sensor input
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Manifold Pressure: Manifold Absolute Pressure from GenericOBD II or other MAP sensor input
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Engine Displacement: Based on the motor, in liters. For example, 2.7 for some Dodge Chargers
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Volumetric Efficiency: Based on the motor. For example, enter 0.67 for 67% efficiency.
You can now assign the economy calculator values to a gauge (pg 13). Use the [<<] or [>>] buttons to select the signal from the
Economy calculator signal list