The reason you sometimes see better number on the dyno is because that engine is still pulling some timing out because of the amount of knock. It's still hearing something so it's still being cautious. This is especially true with most Japanese manufactures because in Japan they have either 96 or 98 at the pumps so that's basically what the engine is designed for. Those gains are also usually seen on more modified engines as well that have higher compression with upgraded internals or with forced induction. Basically, the more resistant and engine is to knock, the aggressive you can be with advancing the ignition (which the ECU will try) and more boost. Seeya.

 

i did some diging on my own and that is the SAME answer i got.. so its safe to say that on juice (just as an example) i MIGHT run SLIGHTLY better at the track with some LOW level unleaded race gas.. than say 91 which i believe is the MINIMUM for a small shot.. i use 94 but i THINK the minimum is 91 (not sure on that its been a while)