Originally Posted by Mad_Hatter
Originally Posted by tiger862
Originally Posted by TiredTrucker
I have used E10, E15, E20, E30, E50, and E85 over the years. We can get these varieties at several blender pumps in our area. Nothing spectacular if that is what you are looking for except each one progressively lower in price as the amount of ethanol increases. Makes sense considering that ethanol is $1.32 on the commodity exchange this morning and gas is $1.68 this morning on the exchange.
Except the cost was 10 cents more. 2.05 for E10 and 2.15 for E20.
Find a new station.
The BTU's of a gallon of gas goes down the higher the ethanol content (inversely proportional). So your best mpg's will be at the E10 level. (the btu's of a gallon of E10 is equivalent to about 96% the btu value of pure E0 gasoline, at apprx 114k btu's). I would only use an E20 if after running the numbers it showed a cost savings (after factoring price, btu difference etc). In my area i can get E10 at up to 92 octane and it's at least a dollar cheaper than E0, which I can also get.
Gasoline Gallon Equivalents
The BTU content thing is correct. But if the pricing spread is right, ethanol laced fuel can still be the better value.
One of my vehicles is a flex fuel GDI engine with 11.2:1 compression ratio. High octane is the name of the game if I want to get full performance from the motor. That leaves either 93 octane Premium ($3) or 100 octane E85 ($1.87). Even with wishful thinking, there is no way that running premium will deliver a high enough MPG improvement over E85 to offset the cost per mile by using Premium. E85 is the clear winner.
If the engine is designed properly to take full advantage of the characteristics of ethanol, then we really would not even be discussing this. There have been engines developed recently that are extreme boosted with diesel equivalent compression ratios that can take advantage of the potential of E85 and those engines give diesel equivalent power and fuel economy. BTU content is only one factor, and that may not be the issue that is touted. Cummins is one of those OEM's who developed one of these engines. But none of those have reached the market yet, so it is all moot.