Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.
Only commenting to say that I have a house in Coronado and planning to move there full-time this year.About 10 days ago I drove from my ranch in Montana to Coronado to deliver a dog that I trained. I then drove back to the ranch. I kept immaculate records of the mileage I obtained using 87 octane in a 2024 F150 Lariat eco boost. Wednesday I received a call from Coronado that the dog chewed apart the handler that was paired with it and they requested a second dog. I almost immediately started to Coronado with a much softer dog as a replacement, except this time I used 91 octane. I made the exact same stops along the way and return. The performance was very noticeable and, when all was said and done, I got 4.8 MPG more with 91 octane.
The no more comment lasted 10 days...
I realize it is not a scientific test, but I was still surprised by the results.Adding boost is like adding compression. It only makes sense that higher octane fuel would allow more boost and timing without detonation. And unless you ran the tank down to empty, your comparison is skewed. Lots of outside factors can also change results such as wind and temperature
interesting comment. E85 octane is 104, but more ethanol you have in tank, less MPG you have , which is normal in fact !I don’t think you’re the only one to report this. I had a similar experience comparing 90 octane no ethanol to 93. I believe @FordTechOne opined that the truck running 93 doesn’t ever have to pull timing to keep from knocking but on lower octane it will, even though you don’t hear any knocking. The truck’s anti knock strategy allows the truck to run on 87 easily enough, but it won’t perform as well and it doesn’t seem to get as good a distance on a tank.
FTO can elaborate on this more eloquently, but it’s not a myth. Some report only a single mpg difference, others more. I think I saw 2-2.5 difference-ish.