octanes

[crazyhorse55]

I live in Texas and we have 87,89,93 octanes.. will the 91 octane tune work with 89 octane? have a 2010 mustang gt

[Mike_Levy]

Try it and log your knock. I wouldn't, but you can try.

[06MonteSS]

yeah, I wouldn't either... use the 93 octane gas, or adjust the 91 octane tune and reduce the global timing by 2 or 3 degrees...

[crazyhorse55]

Will just take tune off. Just filled up with 93 octane. had just under a half tank of 87 octane. Can we get a 89 tune for people that live in Texas ?

[06MonteSS]

contact user tuningss at [email protected] for a custom tune for your mustang, he can getcha set up...

[crazyhorse55]

can I use the 87 performance tune if I put a higher grade octane? Like I said before had less than half tank 87 then filled up with 93.

[tuningss]

You can always use a higher octane fuel with a lower octane tune, just not the other way around. But there is no benefit of doing so. Best bet is to use the matching octane and tune. If you only have 87/89/93, then use either the 87 tune/octane, 93 tune/octane or a custom tune for the 89 tune/octane from a CMR dealer like us. Hope this helps.