You're welcome. Glad I could help. I look for things like that because its worth knowing and I've been working on cars for a while now and the car that I built still isn't done... check the link for my post
Octane rating is a measure of anti-detonation characteristics any fuel has. Racing gas is a whopping 100 octanes, 'cause it's desingned straight for highly compressed engines. Regular gas, say 87 -89 RON would experiment "diesel effect" on those firing chamber, exploding before spark is present due to the high compression it suffers when piston's reaching its upper point. Tetraethyl-lead or other non-leaded additives make gas less prone to premature exploding.
Thats why a vehicle that doesn't have forced induction or an engine that has been built with bigger cams, stronger pistons and rings, sleved doesn't need need higher octane fuel. Its because it has been tuned at the factory to run better off the lower octane fuel by evening out the air/fuel ratio's and when the sensors detect a change due to elevation/ temp/ humidity it will either retard or advace the timing to smooth out the Air/Fuel Ratio by adding fuel or taking fuel. Every engine has detonation thats why tuning is important when building engines.
I've become used to running 93 because of my last (modded) truck. I've been running 93 in my 09 5.7L for the same reason I run Royal Purple oil; to keep it cleaner longer (The dumbest thing is I only use Shell V-Power [mind thing I guess]). The price difference between 89 and 93 is like $2 or $3 for a whole tank AND YOU DO BETTER MILEAGE so what the hell.
Having said that, I'm now wondering is the 93 HURTING the engine? And how?
Can the experts out there comment on ethanol free gas and it's effect on the engine? I can get and put 92 Octane non-ethanol in my GT500 at the advice of my tuner but I'd like to hear the skinny on this too.