Octane is simply the resistance to engine knocking. It doesn't clean anything. I don't have anything that requires 93 but our SUV requires 87. As long as we're above 1800' in altitude, 85 works every bit as well. Do some reading on how low in altitude you can go before you really need 93. If you're fairly high, you might get along fine with as low as 87 unless you take a trip to some low place. They rate them close to sea level so everyone can use them. The car's computer will compensate to some degree.
