Quote:
Originally Posted by KSpeed Auto
My logging software cannot log "knock counts" on Subaru ECUs, and I don't know of any that do. I watch three things : IAM (Ignition Advance Multiplier), FBKC (Feedback Knock Correction), FLKC (Fine Learning Knock Correction).
I can hook up to a stationary Suibaru with the laptop and read IAM, and the whole FLKC table in a matter of seconds, so I do this to lots of cars. When I have done this to some stock STI's, I have seen IAM<1 and FLKC in the -1 to -2 range in many places. Basically what this means is the car is knocking and the ECU is pulling timing. In general you want the IAM to be 1 (or 16 on earlier WRX) and the FLKC table to be all or almost all 0's. I have seen stock STIs running great like this too, so there is variability between cars, and/or weather, and/or fuel quality. The conclusion I draw is that the stock STI tune is a little on the ragged edge for our shitty CA91 octane.
A "Stage 1" tune on an otherwise stock STI will fix this while at the same time adding power by increasing boost and by optimizing timing and fueling.
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It can reads knock counts but as you said its in FBKC, so -1.4 is 1 count-2.8 is 2 etc... The stock tune is pretty much crap, but subaru did it and if they blow up then is warrantied. I understand you can always flash a car back to stock and everything, but unless you want the most out of your car with pretty much zero mods then a tune isn't necessary