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Data Logging Instructions
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(Cobb or Open Source factory Subaru only... standalone EMS please contact me for details)


There are different classifications of data logging and each has their own requirement for which parameters to log and how to drive the car during log collection. If you do not know the basics of data logging, including how to download them to your computer, please familiarize yourself with the process by reading the manual or watching manufacturer videos.

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General Guidelines

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  • Don't log more than you need to. Only start the data log right when you are about to begin and immediately stop the data log afterwards. Unless doing a long mixed driving log file, data logs that are too long will be rejected.

  • Log the correct parameters (see below). Logs that do not contain the correct parameters will be rejected.

  • Don't log extra parameters that are not in the lists below. Extra parameters slow logging and clutter the file.

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Parameter Sets


Use the following parameters for the type of log(s) that you have been instructed to collect:

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Initial Idle and Mixed Driving

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Allow the car to warm up for 5-10 minutes then drive it without boost, at various speeds, for a period of time no less than 5 minutes and not to exceed 15 minutes while at full operating temperature. Data log the entire process.

  • RPM

  • AF Correction #1

  • AF Learning #1

  • AF Sensor #1 Ratio (AFR)

  • Coolant temp

  • Intake air temp

  • MAF voltage

  • Calculated load/Engine load

  • Throttle position

  • Boost/manifold pressure

  • Ignition timing

  • DAM/IAM

  • Wastegate duty cycle

  • For Cobb users who have integrated a wideband AFR gauge into their factory ECU (ECF-1, AEM UEGO, etc) and are using Cobb AP V3, please also datalog Sensor Only Input Monitor (Rear O2). If you are using a Cobb AP V2, please datalog AF Sensor #3 Voltage.

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Partial Boost Pull
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Put the car in the gear you have been instructed to use. Using care, perform a 30-40 percent steady about of throttle (keep the pedal pressed down the same amount, do not vary or oscillate) and let the car accelerate through the RPM range. Once you run out of RPM the run is complete. 2nd gear begin at 2000 RPM. 3rd gear begin at 3000 RPM. 4th gear begin at 4000 RPM.

  • RPM

  • AF Learning #1

  • Coolant temp

  • Intake air temp

  • MAF voltage (unless you have no MAF sensor anymore, then do not log)

  • Calculated load/Engine load

  • Throttle position

  • Boost/manifold relative pressure

  • Manifold absolute pressure

  • Ignition timing

  • DAM/IAM

  • Feedback Knock

  • Fine Knock Learning

  • Wastegate duty cycle

  • Injector duty cycle

  • Vehicle speed (mph)

  • For Cobb users who have integrated a wideband AFR gauge into their factory ECU (ECF-1, AEM UEGO, etc) and are using Cobb AP V3, please also datalog Sensor Only Input Monitor (Rear O2). If you are using a Cobb AP V2, please datalog AF Sensor #3 Voltage.

  • Ethanol final (FlexFuel users only)

  • Fuel pressure final (Fuel pressure users only)

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Full WOT Boost Pull

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Put the car in the gear you have been instructed to use. Hold the vehicle at the starting RPM and immediately apply wide open throttle and let the car accelerate to the end of the gear. Once you run out of RPM the run is complete. 2nd gear begin at 2000 RPM. 3rd gear begin at 3000 RPM. 4th gear only use if instructed and RPM will be provided.

  • RPM

  • AF Learning #1

  • Coolant temp

  • Intake air temp

  • MAF voltage (unless you have no MAF sensor anymore, then do not log)

  • Calculated load/Engine load

  • Throttle position

  • Boost/manifold relative pressure

  • Manifold absolute pressure

  • Ignition timing

  • DAM/IAM

  • Feedback Knock

  • Fine Knock Learning

  • Wastegate duty cycle

  • Injector duty cycle

  • Vehicle speed (mph)

  • For Cobb users who have integrated a wideband AFR gauge into their factory ECU (ECF-1, AEM UEGO, etc) and are using Cobb AP V3, please also datalog Sensor Only Input Monitor (Rear O2). If you are using a Cobb AP V2, please datalog AF Sensor #3 Voltage.

  • Ethanol final (FlexFuel users only)

  • Fuel pressure final (Fuel pressure users only)

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Diagnostics

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The following is used for diagnostic collection.

  • RPM

  • AF Learning #1

  • AF Correction #1
  • AF Sensor #1 Ratio AFR

  • Coolant temp

  • Intake air temp

  • MAF voltage (unless you have no MAF)

  • Barometric pressure/Atmospheric Pressure

  • Battery voltage

  • DAM/IAM

  • Roughness #1-4 (04+ STI and 06+ WRX only)

  • Throttle position

  • Vehicle speed (mph)

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