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ECU Tuning Files
For tuners and dealers

Data logging guide

What to record when you data log a car for a tuning file. Use this as a template and attach your log files to the file request.

  • Scan for fault codes first
  • Petrol and diesel lists
  • VCDS logging tips
Before you start

Scan for fault codes first

Scan the car for fault codes and note them down before you log anything. Then log the values below, fill in the original and modified maximums, and attach the log files to your file request.

Petrol

Petrol data logging

ParameterOriginal max valueModified max value
Engine speed
Airmass
Injection opening time
Lambda specified
Lambda actual
Inlet air temperature
Exhaust gas temperature (EGT) (900/960)
Boost pressure specified
Boost pressure actual
Wastegate duty cycle (VAG = N75)
Ignition
Retarding ignition cyl. 1
Retarding ignition cyl. 2
Retarding ignition cyl. 3
Retarding ignition cyl. 4
Diesel

Diesel data logging

ParameterOriginal max valueModified max value
Engine speed
Airmass
Injection quantity
Injection opening time
Lambda
Inlet air temperature
Exhaust gas temperature (EGT) (850/900)
Boost pressure specified
Boost pressure actual
Wastegate duty cycle (VAG = N75)
Tips

Logging with VCDS

  • On VAG models, press the "Turbo" button and then the "UDS" button (to the left of Turbo) after choosing your values. UDS is not available on every car.
  • The logging speed shows on the left of the VCDS screen. It should be at least 4.
  • If it is lower, log fewer values at once and make a second log with the rest.
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Logged on our own rolling road

BMW M5 Competition on the dynoLamborghini Huracan on our 4WD dynoBMW M3 Competition on our rolling roadWorking under an Audi on the lift

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