would like to hear some inputs about that. I only know that if it goes below 100, ecu is interpolating with low octane maps. but in what cases it goes below 100, at how many counts of knock, how fast or when it reverts back to 100 etc.

 

I've got an example on a real dyno

096s - 5843rpm 5knocksum (100%) (really bad knock spike 142adc/79base)
098s - 6281rpm 9knocksum (99.608%)
103s - 7687rpm 13knocksum (96,471%) -6°timadv

it goes down when pulling timing doesnt work anymore I guess ? It's a slow linear decrease unlike knocksum, my log stops 2s (105s) after he lifted off but octane was still the same 96%

strangely the power curve barely goes down, must be a dyno "thing" because you definitely see it fall on a road dyno and with a lot less knock
both timing+octane are not enough to prevent knock that's for sure, in my case knock was because of the poor bench ventilation (0-2 knock on the road) so that's the only time I saw that, don't even log octane usually, no point

edit: no idea what the afrs were supposed to be without knock at that time so can't say if it became really rich or not I don't think so, maybe 10.2 instead of 10.7 at 7700rpm something like that

 

When there is more than 7 knocksum, the ECU starts decreasing the octane flag. When you go into boost and don't get less than 7 knocksum, the ECU starts increasing it again towards 100.