[GP86]

Originally Posted by JCunningham

I dont see why the fuel economy thing would make a difference if its capable of getting the required fuel mileage with one fuel then what's it matter if it doesn't with a different fuel when it can run both and one produces fewer emissions doing it.

I honestly do not know, just a hunch. But, we know that FlexFuel nets you fewer MPG compared to gasoline. There must be something in the rating from the EPA that takes this into account.

If you get less mileage on FlexFuel, but you have far less emissions, does it cancel itself out? It could. I am going to try to find this out.

Here is an excerpt from Wikipedia that sheds a little bit of light. I still need to dive in a bit deeper.

For the fuel economy calculation for alternative fuel vehicles, a gallon of alternative fuel is deemed to contain 15% fuel (which is approximately the amount of gasoline in a gallon of E85) [22] as an incentive to develop alternative fuel vehicles.[23] The mileage for dual-fuel vehicles, such as E85 capable models and plug-in hybrid electric vehicles, is computed as the average of its alternative fuel rating—divided by 0.15 (equal to multiplying by 6.666) -- and its gasoline rating. Thus an E85-capable vehicle that gets 15 mpg on E-85 and 25 mpg on gasoline might logically be rated at 20 mpg.

But in fact the average, for CAFE purposes, despite perhaps only one percent of the fuel used in E85-capable vehicles is actually E85, is computed as 100 mpg for E-85 and the standard 25 mpg for gasoline, or 62.5 mpg.[12] However, the total increase in a manufacturer's average fuel economy rating due to dual-fueled vehicles cannot exceed 1.2mpg.[24] Section 32906 reduces the increase due to dual-fueled vehicles to 0 through 2020. Electric vehicles are also incentivized by the 0.15 fuel divisor, but are not subject to the 1.2 mpg cap like dual-fuel vehicles.