Max compression ratio for regular gas? [Archive] - THE H.A.M.B..
So apparently I should be running 91 Octane now!!!
This is for maximum efficiency and performance. However, given the cost of premium it is not "needed." Apparently, you multiply your compression ratio by 10 to find out your maximum efficiency octane.
Obviously the mpg and hp increase would not be worth the extra cost to you lucky individuals with 87 unleaded. Seeing as how I have no choice, I think I'm going to go with premium. Looking at my owners manual it says 86 octane or higher. It also says UNLEADED ONLY in all caps and bold. Also says this on the gas cap itself. Certainly seems like octane isn't a big deal to Honda, but ethanol is...