I buy 93 octane. If thats whats actually dispencing or not is another story.

You can run with lower octane, but you increase knock count. Once knock count reaches some limit the ECU retards timing. It takes 4 degrees of retard to quench the knock of 1 degree too much timing.

More timing gives more power and mileage. Some of you have posted in the past that you get better mileage from resetting the ECU. This is reseting the timing table back to zero. You should not have to do this if you have enough octane to keep the knock sensor happy.

I'm guessing that you can go farther per dollar on the higher octane because of the increased timing.

It would be very hard to prove this without running several tankfuls of each gas through to get the ecu set to each gas. Resetting the ECU gives the lower quality gas a temporary mileage advantage.

John C.