1 to 4 ratio.
1 part (110 octane) to 4 part (91 octane), what octane am I running?

 

Hmmm, unless there is something tricky with this that I don't understand, simple math should work.

91+91+91+91+110 = 474
474/5 = 94.8

 

Nothing tricky about this. I had a chance to go to Infineon Raceway this weekend and fueled up with 8 gallons (approx.) of 91 octane and 2 gallons of 110 octane.
Does anyone know if I was to put 100% 110 octane, what will it do to my engine good or bad?
P.S. they also have 114 and 118 octane as well. Unfortunately they were out of 96 and 100 octane.

 

It won't give you any noticable benefit unless your regular premium gas is bad. May possibly harm your car with unburnt fuel in the catalytic converters.

Try searching for 'racing gas' and you'll find a few threads.

https://www.clublexus.com/forums/sho...ght=racing+gas
https://www.clublexus.com/forums/sho...ght=racing+gas
https://www.clublexus.com/forums/sho...ght=racing+gas

 

Davegs4 thanks for the links. Much help !

 

Yeah, there's no reason to use racing fuels for your stock IS300. It's not gonna help you one bit unless you have the big mods that need that high octane.