Interesting. I tried this as well, filled up with 28 gallons of ethanol free 91 octane, and drove around 300 highway miles getting barely 17 mpg. Went back to the cheapest 87 octane 10pct ethanol and am getting over 20mpg.I go where the gas is cheapest. I have not noticed any difference when using various brands. I have however noticed that I get better fuel economy with 10% ethanol than with 100% gas.
I would agree with this statement 100% and would laugh at anyone that disputed this, but my real world numbers with the EcoBeast dispute this. I track my economy with every tank of gas, and when I have used real gas my economy has dropped by 2 or more mpgs Avg.Run the lowest octane fuel that your engine can operate on and you will get the best fuel economy. All octane does is make the fuel harder to ignite. That kills fuel economy. Higher octane fuel is necessary in some engines or instances when you'd get 'pinging'/detonation from lower octane fuels. Your 'High Peformance' cars that run high compression ratio engines and aggressive timing need higher octane to ensure the sparkplug ignites the fuel instead of it pre-igniting ...again 'ping'/detonation. Technology today has allowed us to have 10:1 compression AND twin turbos AND run 87 octane. Take advantage of it. As far as ethanol goes the facts are that is only has half the BTUs as gasoline. So 10% ethanol fuel nets 95% of the BTUs that 100% gasoline does. It is a 5% weaker fuel. To put it into nice round numbers, in conditions that you'd get 20 mpg on eth fuel you'd get 21 mpg on 100% gas. I do the math on the price per gallon and make the decision based on how much am I paying per mile. If ethanol is $3.50/gal and GAS is $3.65/gal and I'm getting 18mpg average in my conditions then with ethanol I'm paying 19.4 cents per mile to drive the truck with gas I'm paying 19.3 cents per mile (you have to add .9 to 18 to get the milage gain from GAS). So as you can see it can be a difference of splitting hairs when it comes to cost but GAS does give you 5% more range as well. I worked as a Refinery Lab Tech for 13 years. Too often folks fall for the stigmatism that is 'PREMIUM' fuel. That word 'Premium' sounds like it has better ingredients or better quality. It doesn't. Its there to sell it to you. Look at the octane rating as you would your shoe size. Do you buy size 14s when you wear size 10s? If you are going to be in HIGH engine load conditions then higher octane will be beneficial. If you are running performance tunes then higher octane will allow more boost and timing. If you are just routinely driving your truck under normal everyday circumstances then don't bother wasting your money.
While I respect your findings there is truly no way to accurately test the differences in our trucks on the road in the real world. Under controlled testing conditions ONLY can you see and measure the EXACT differences. Remember you are also trusting the gas stations and fuel truck operators to deliver what you are buying. Do not think that 100% GAS hasn't ended up in fuel tanks that typically hold the 10% eth fuels and vise versa. A friend of mine drove a fuel truck and the things that happen like unloading regular 87 into the premium tanks by mistake are not unheard of..... Even when conditions lend themselves the most to duplication of testing environments you still have the human element of the driver. Truth is the difference in eth and non eth is not worth mentioning money wise. I fully support the decision to do what you are comfortable with. I know how you feel. You may CONSISTANTLY find your results support your decision but what does it mean when I find that non eth fuel gives me better economy? This is a situation where real world tests are not going to give you accurate 'laboratory' precision results. Its best to do what works for you with the eth vs non eth.I would agree with this statement 100% and would laugh at anyone that disputed this, but my real world numbers with the EcoBeast dispute this. I track my economy with every tank of gas, and when I have used real gas my economy has dropped by 2 or more mpgs Avg.