Around 1985 the lead content in leaded gasoline was reduced to 10% of the previous standard. The sale of leaded gasoline was discontinued 4 to 5 years later. Ethanol was already in use at that time but less publicized. In the late 1970’s, gasoline w/ethanol was advertised as “Gasohol”.
In my area E10 was the mandatory winter fuel supply in the late 1980’s.
I have no evidence either way and never checked mileage. It just seemed like the needle was moving downward faster that normal. Plus co-op is a farmer owned organization, so no franchise to lose. They can do what they want. I can’t say that Minnesota required it. Maybe but never noticed it before.
Here’s my question on going over 10% - why do it? Ignoring potential issues with the fuel system, I still see no benefit. Lost fuel economy is the major result. I bet few stock street engines can take advantage of the increased octane.
All I know is both my more modern vehicles say in the manual: “Do not use gasoline with more than 10% ethanol.” 2017 Chevy Volt and a 2006 Harley Electra Glide. I am not going to use E15 in those vehicles. Now, I do own an old 1975 Suzuki motorcycle (GT750) that was designed way before E10 gas came out. Only Non-ethanol in that bike.
I’m not familiar with MMT. Where in the US is it used? I read the Wikipedia article and while it said that the EPA allows usage, several car manufacturers won’t underwrite performance of their vehicles if MMT treated gas is used. That’s in addition to the Toyota warning that @davesmopar posted.
Those vehicles were emissions certified using up to 10% ethanol blend. In the early 2020’s vehicle manufactures made the necessary software adjustments for E15.
In Sioux Falls when they had a price war, I could fill my VW up at 19 cents a gallon. So a full tank at less than $2. For years though normal price was $0.32.9.