Thats weird, because when I put in 87 octane in my 2K Si my average milage per gallon droped (the average was 21MPG). I ran three tanks just to see if it was a fluke. When I use 93octane my average is 27MPG. Stock compression ratio 10:2:1

 

I had similar results with my 02 Scooby (Impreza WRX). I guess that is why I like to think that if I put the higher octance in my 4Runner that I'll get better gas mileage.

 

I run 42 octane!!

oh you mean on my yota not in the diesels.....LOL

had to use 93octane in my 3vze for all the carbon deposits, else she'd ping like a marble in an empty 1gallon paint can in a mixing/shaking machine. I look forward to using low test again w/o any ping!...

 

Not true.

I bought a 94 truck with the 22re brand new, and then went back and bought my current truck brand new also with a 22re, and neither truck has ever been able to run on anything less than 91 octane without pinging.

Maybe I have better ears than most people or something, I don't know. I just know that it used to be quiet on 91.

For whatever reason now though I can't stop the ping even with 93 completely...

 

Can't argue with your results obviously. As others are stating, what that would mean is you are losing efficiency with the lower octane gas, despite more potential energy available with the lower octane. You might try 91 and see if that saves you any money

 

the only reason to be getting lower gas mileage with the lower octane would be if the knock sensor is telling the computer to change the timing.

 

Well; around here it's tough to find 91 octane. Thats why I use the 93. I even ran 89 for a few tanks and the MPG loss wasn't as bad but it was def was there.