benefits of using 100 octane fuel on mirage?

[91cavgt]

To my knowledge the higher octane was for Bigger V8,s and if your car started pinging. So a smaller motor like the Mirage runs faster then a V8 so you don't need a higher Octain

The octane rating has nothing to do with the size of the motor. It is all about compression ratio, ignition timing, and rpm. For example, a Chevy 8.1L V8 is rated to use 87 octane, but my old scooter, which was a 163cc, needed premium 93 octane. The scooter had a higher compression ratio and more agressive ignition timing than the big block V8. But an old school Kawasaki Ninja 250 which had 12.5:1 compression would run fine on 87 octane, primarily due to it's MUCH higher power band (7k rpm to 13k rpm).

[debburyl]

Ok, I know my old 67 olds delta 88 said to put supreme fuel in it.

[Dodger]

yep in higher compression eng you want your fuel to burn slower to avoid pinging all higher octane fuel does is burn slower

[91cavgt]

Ok, I know my old 67 olds delta 88 said to put supreme fuel in it.

The old engines were typically high compression and had a lot of timing advance as well. The old gas was also leaded to help increase the octane rating. When lead was outlawed as an ingredient in gas, you usually had to run premium in order to prevent knock.