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Parameters to Log and Definitions


Lambda (Bank 1) – Internal wide-band oxygen sensor bank 1.
Lambda (Bank 2) – Internal wide-band oxygen sensor bank 2.
Ped Pos. (%) – Accelerator pedal position.
TPS Act. (%) – Actual Throttle position.
Timing Cor. (1-6) – Individual cylinder timing correction in degrees.

  • Timing corrections should remain as minimal as possible, with that said small timing corrections are a part of the N54’s elaborate ignition control strategy. When logging all cylinders corrections under full throttle, consistent corrections across multiple cylinders or incremental corrections indicates excessive engine noise and is a sign that the map might be too aggressive for the mechanical condition of your vehicle.

Timing Cyl. (1-6) – Ignition timing in degrees before top dead center.

  • This is the final commanded ignition timing after all correction and adjustments.

Load Act. – Actual calculated engine load value.
Load Req. – Requested calculated Load from the ECU.
Coolant Temp. – Engine coolant temperature.
Engine Oil Temp. – Engine oil temperature.
Charge Air Temp. – T-Map sensor value of charge air temperature.
Boost Error – The Difference between Boost mean and requested.
Req. Boost Abs. – Requested boost calculated by the DME in an absolute value.
Boost Mean Abs. – A rolling mean average of boost.
Boost Set point Factor – Boost pressure set point factor utilized by WGDC system.
Boost – Manifold Absolute Pressure.

  • This reading is pre-throttle body, boost spikes during shifts or on the release of throttle is normal. The system will build pressure during the short time the throttle closes and before the diverter vales open.

RPM – Engine speed in revolutions per minute.
Vehicle speed – Speed calculated by vehicle speed sensor.
Wastegate Duty Base – Base percentage of wastegate solenoid duty cycle (0 to 100%).
Wastegate Duty After PID – Percentage wastegate solenoid duty cycle after system PID control (0 to 100%).
Wastegate Duty Bank 1-2 % - Percentage of actual wastegate solenoid duty cycle at bank 1 (0 to 100%).
STFT 1-2 – Short term fuel trims for bank one and two displayed in %. (See LTFT for description)
LTFT Bank 1-2 – Long term fuel trims for bank one and two displayed in %.

  • Fuel trims refer to adjustments being made by the DME dynamically to the base fuel table to get the proper air fuel ratio. Short term fuel trim refers to adjustments being made in response to temporary conditions. Long term fuel trims are used to compensate for issues that seem to be present over a longer period. Fuel trims are expressed in percentages; a positive value indicates lean (DME is adding fuel) and negative values indicate rich (DME is subtracting fuel). On the N54 Fuel trim banks refer to the 3 cylinder banks related to each turbo. Fuel trims are generally calculated by using a wide set of data values, including pre-cat O2 sensors, intake air temperature/pressure, ECT, knock sensors, engine load, throttle position, and even battery voltage can effect fuel trim. Long term fuel trims generally should not exceed +- 10%, while short term trims at idle should be in the +- 3% range. The N54 has the ability to adjust up to +- 34%.

Fuel Mode – Displays the DME current fuel mode state.

  • 2 = Normal 
  • 10 = Catalyst Warm-up Mode (Also active for a short period after flashing the DME.)
  • 20 = Spool mode
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