Quote:
Originally Posted by Td-d
No prob, there's a lot of information hidden on the RR forums over the years. Not really - it's a more reactive process - basically you have the base timing, and then the knock correction advance, compensated for with the various parameters (i.e. FBKC, FLKC, and IAM as a multiplier) and that's the timing. There are 3 knock control 'levers' - IAM is the so-called 'rough correction' mode, and will drop all timing in the KCA by a %. FLKC is learnt over time and stored in ROM defined 'cells' whilst FBKC is immediate.
|
Thanks! Excellent explanation. I've speculated for some time now that ignition timing was learned and adjustments stored much like fuel trims and now you've confirmed it for me. FLKC is like LTFT, FBKC is like STFT and IAM is a failsafe not really needed for fuel trimming.
Quote:
Not suggesting that, nope - I haven't seen the part numbers, but I would not be surprised if it is the same knock sensor that is used across most of the Subaru platforms. Just saying that consumer grade knock sensors have their limitations. On JV's tunes - really, I can't comment, and frankly am not interested in commenting - I avoid internet drama like the plague  Besides, I'm half way across the world (literally 8000 miles!). I'm here for the techie info...
|
Agreed on the knock sensors but to my old school car guy mentality, even consumer grade sensor/ECU components impress me. I started out with a 1968 vintage 396 Chevy BB and TBH I prefer modern EM systems to the old distributors and points.
Quote:
|
I would agree that on an N/A platform it's less likely to as big a problem (I don't own a BRZ incidently, have an STI). On FI, due to the nature of Subaru's pistons (hypereutectic, not cast) and the compromises made for emissions over the years, on-going knock is bad news, and will likely take the rings out, if not worse. But I cannot (and won't) pretend to know much about the FA20 - there are smarter people out there! I would expect these engine to be more not less knock resistant given the direct injection into the chambers.
|
I'm no FA20 expert either but that makes perfect sense to me. As for JV, I can't help but feel that it was his sometimes caustic personality that has made him such a pariah on this forum much more so than his tuning capabilities.