Originally Posted by Rayme
I know that E85 gas usually results in poorer gas mileage due to less energy per volume..so that means "using that example" that getting gas from Shell results in poorer gas mileage than another random gas station what uses pure gasoline???
Has somebody researched this before?
Well, when RFG was mandated by the EPA to the Milwaukee metro area in the late 90's, here's some things I learned.
First, the expansion of ethanol is different than gasoline. It's made in huge batches too. So, first, recognize that we're talking hundreds of thousands of gallons in each recipe. Next, if it's made within spec the 10% ethanol, by volume adds about 2.8% oxygen to the mixture, but the law allows a variation between 1.7 to 3.5% oxygen, which is a swing in the volume of ethanol because of production mixing and by expansion and contraction through temperature changes.
Finally, gasoline isn't very different from manufacturer to manufacturer because of a lot of the Clear Air Acts from the early 90's. Gasoline is a fuel that is important to have in the supply chain, so it's distributed to everyone. Just because you have a Shell station, for example, it doesn't necessarily mean that it was made by the Shell manufacturing. Sure, it probably came in the tanker that it usually comes in, but it's origination is not known. It's in the retailer, manufacturer, and the distributors best interest to keep the supply moving.
I don't like ethanol mandates. It should be a choice.