Water/Meth injection

WarmAndSCSI

We have 91 exclusively in Utah because of our elevation. Being 4500+ ft up, we can get away with it since all engines up here have greater detonation resistance with the lower air density.

For California, I think it has something to do with a combination of the oil companies and CARB regulations. Apparently it's pretty difficult to make a 93 octane gasoline that meets all of your emissions requirements (including oxygenation). Only one company - Unocal - had a process to produce a 92 octane fuel for California's most recent requirements. Unocal is apparently defunct now, so nobody is licensing that process any more. Cost is the major factor, however. The price of 93 would be just that much more on top of your already outrageous gas prices.

This is just paraphrased on what I knew before and what I just read... could just be conjecture on somebody's behalf, but it sounds logical.

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