Saving Gas And Better Mileage By Changing Fuels With Ethanol and Non Ethanol In My Ford Focus

One night over dinner, a friend of mine a was telling me that he recently switched to non ethanol gas for his car and was reporting some excellent gas mileage. Now I'll admit, he drives a stick shift Ford Fiesta (yes they exist, they are just difficult to find) which should get pretty good gas mileage anyway. I figured I drive a Ford focus with a slightly bigger engine, and pondered if I would get the same results. I then set out on an epic fuel experiment! I decided to try each of the grades of gas to find out which one provided the better fuel economy. As my friends will tell you I'm a bit of a nerd when it comes to Excel, so it should be an easy process right? Not so much.... But here is what I was able to find:

For starters, I suppose I should lay out some of the rules of my experiment. I judged it just right when I went to full up on non ethanol gas, and coasted into the station on fumes in an effort to purge any remaining ethanol from my tank. I then attempted to use the same gas station, at the same pump each and every time I went to fill up. I am assuming this will give the most consistent results. I then decided that 3 fill ups would be enough to give an accurate estimate of my gas mileage. I drive a combination of both highway and city miles, so I think I am a typical driver. The gas rotation I decided on would be non ethanol gas, Regular, Mid, and High Grade. I also figured this would also help with the higher octane levels the higher up in grades I went.

So I set out on this experiment in October and finally finished in January, driving over 4000 miles in the process. I was a bit surprised at my findings. At first I thought that the non ethanol gas was very efficient, but then I realized I only had 2 data points :( If you attempt this experiment, you need to ensure you record the mileage when you begin, and end. SInce I forgot the reference point for mileage to start out with, I only had two data points. There was quite a difference, so the average is probably off a bit. Even with only 2 data sets, I found that I was averaging 33.7 miles per gallon. The regular gas averaged 33.1 MPG, Mid Grade 30.6, and Premium Gas 29.2 MPG.

Although the non ethanol gas appears to be more efficient, it also costs much more per gallon. On average about $.76 more per gallon when compared to regular gas. In comparison the premium was usually around $.20 more per gallon. I discovered that the slight increase in fuel economy wasn't worth it due to the price. In addition, non-ethanol gas isn't widely available. In fact we only have 1 single station in the county that offers it, which is why it's probably a premium price.

After I calculated the MPG, I decided to really bring these figures into focus. (I drive a Ford Focus, get it? ;) I decided to check to see what was cheaper per mile on average. With the higher price per gallon, the non ethanol gas came out at $.120 per mile driven, with regular being $.105, mid grade $.110 and premium coming in at $.119 per mile.

My final analysis and recommendation is that regular gas is actually not only the cheapest option for me, but also the most efficient! Unfortunately I went through all this trouble only to determine that the type of gas I was already using was the most appropriate anyway. Now I must concede that there were differences between my car and my friends, and that I'm not taking into account long term cost of ownership. It is also rumored that non ethanol gas is actually better for the engine, and has fewer long term detrimental effects. This opens up a different conversation all together about spending a little more on gas to keep your car running in top top shape longer, but for now I think I'll just stick to my regular gas.

If you would like the XL spreadsheet I used to do your own gas experiment, please let me know in the comments section and I'll email you a copy.