Not available here . What would be the advantage of this?
E85 has an octane of 100-105.
Ethanol % varies based on location (there’s an acceptable range for both), but let’s assume Your 91 pump gas has 10% (E10) and your E85 is E70 (70% ethanol and 30% gasoline).
Using a 36 gallon tank, we will fill with 26 gallons of 91 (E10) and 10 gallons of 102 octane E85 (E70).
This would give us a full tank of fuel at 94 octane, E27.
The ethanol has less BTU’s (energy) than gasoline, but we are only increasing the overall % by 17.
There will be some loss of mpg, but there will be an increase in power and slightly cooler fuel charge which turbo engines seem to like, especially in hot ambient temperatures.
The biggest factor is cost. The average price/gal (today) of E85 is about $1 less than regular 87 E10 and just under $2 less than premium gasoline.
The loss in mpg is usually offset by the lower $/gal and you have a higher octane fuel.
I don’t use it in my truck because it only gets used about every other weekend and we all know the perils of keeping unused E anything sitting too long.
I do use E30 in my daily driver, Kia Stinger GT 3.3T with stock tune and it runs great.