When I ran E85 on my Rappy F150 (with bigger injectors and a @GooseTuned treatment) my mileage dropped to about 11 mpg. It was lower than that at the beginning cuz “holy crap this truck is fast” but even driving normally it was rough on consumption. I did the swap for performance but I did do the math and it was a wash on saving any cash. Eventually just swapped back over to 91 as it was difficult to find E85 outside of the town I was in.Well, the right answer is "almost all of them".
But more to the point on ta thread about tunes, I would not mind having the option to run an E30 mix of 87 and E85 for an anti-knock rating of about 91. Such a mix would be a real $ savings compared to buying overpriced (which can be up to a full dollar more in my area) 91 pump.
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