Originally Posted by Stohlen
Except that you want to put in 30% ethanol, not 30% E85.
Gasoline is usually 15-20% ethanol, E85 is obviously 85%ish ethanol.
So estimating 10 gallons of fuel. You'd want to add 8.5 gallons of 93 octane and 1.5 gallons of E85. This would give you an estimated 29.75% ethanol content. Or E30 fuel.
E85 doesn't mean there is 85% ethanol in it, it means it can contain up to 85% ethanol. There is usually a disclaimer that states that E85 has a minimum of 70% though. This usually varies depending on the season (less ethanol during winter months).