updates:
Same ECU different car (audi TT MK1), i put K-line direct to ECU, ground and 12 V from OBD port. I start logging while engine is off, then start engine and logger work without problems. I put sample time to 30, sometimes on 50 it break connection.
So I can confirm logger is working on 512 kb 8N090601AB ECUs also
Just be carefull about logging > 20 hz or many variables.
If the ECU load goes above 95-96% you can have "Ignition cut-off" for a split second. The ECU overloads and have to reset. you will really feel that in your car. Its almost the same as removing the MAF sensor and hit full throttle
for 512Kb ecu (C ecu s4 b5), it looks like its not a problem. I can read 80 variables att 20 Hz --> The ecu load is still under 90%
For 1024kb ecu (like M/F/K for s4/rs4 b5) i dont recommend driving with 80 variables att 20 H, because ECU load will be close to 95-96%. Only do it during a pull.
For daily driving and logging, im running 30 variables att 10 Hz on my 1024Kb ecu. Never had "ignition turnoff" with this setup. I have problably over 300 hours logging in the car.
