well for SCR, bikes would be a prime example...for instance a kawi ZX10, last i recall it was like 12.8:1 or just about. and they recommend 90+ octane rating but people who have run 89 in it have not had any issues with pinging or anything. i've never personally done it, and i dont know if it has a low octane fuel/timing map built in like i know some cars do, but bikes usually always have a high scr...my SV had 11.5:1 and i ran 87 in it all the time.