First Name: Tom
Join Date: Oct 2015
Location: SF Bay Area, CA, USA
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In general using Premium when Regular is specced makes rarely sense, since there are most likely no gains. Using Regular where Premium is specced does usually not damage anything thanks to timing being automatically retarded to prevent knocking, but comes most often with a noticeable power loss. My Audi, which specs Premium fuel, does get worse gas mileage and has less power with Regular.
Also, the denser the air, the more readily/uncontrolled fuel detonates. That's why at high altitude, where the air is thinner, you will find gas with slightly lower octave ratings.
Last edited by lamont; 02-15-2016 at 02:50 PM.