I wouldn't go over 11.0:1 or so without a tunable ECU like hondata/etc. I've seen 12:1 run on pump gas with hondata...but a lot of timing was pulled out. I had a friend running 13:1 on the street, and he had to mix 2 gallons of Toluene with each tank of gas...and he was running a J&S Safeguard.
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2015 Ford Mustang GT Fastback - Ingot Silver - 6M - Performance Package - Gibson Catback, JLT CAI, FR 47lb injectors, BAMA E85 tune, Eibach Sportline, BMR wheel hop kit, UPR oil separator, Steeda shifter bushing/bracket
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