> I'm not sure what you mean by E-10. Basically all gasoline that is sold in the US is E-10. You have to look hard to not get E-10. I doubt you have performed t

> I'm not sure what you mean by E-10. Basically all gasoline that is sold in the US is E-10. You have to look hard to not get E-10. I doubt you have performed the experiment you described, for the simple reason that it's hard to find gasoline that's not mixed with ethanol. It's not really productive to make assumptions. Where I live I can buy non-oxygenated gas at almost every station. And, yes, I actually do this experiment all the time given I'll drive to places with a trailer where I'm forced to run an ethanol blend. I realize my comment conflated two things: the reduction of performance and the difference in power per straight gallon. My point is that even with a minimal blend you can lose significant mileage / power. The easiest layman's way to measure that is in MPG. And, yes, there is a significant drop in both power available and MPG. And for reference [0]: "Due to ethanol's lower energy content, FFVs operating on E85 get roughly 15% to 27% fewer miles per gallon than when operating on regular gasoline, depending on the ethanol content. Regular gasoline typically contains about 10% ethanol." The above is in normal driving. So, no, I'm not making my statement up. [0] https://www.fueleconomy.gov/feg/ethanol.shtml https://www.fueleconomy.gov/feg/ethanol.shtml