I just got a tank of 87. I didn't notice any knocking or pinging so far, even under hard acceleration, and heavy load. Maybe I'll jot down my mileage and see how many miles I get out of a tank, then try the same thing with 89 and 93, like BigMike has done. It seems as though detnoation won't be an issue, so now I just have to figure out what octane may give me the best mileage and value.