These repeated fuel threads are funny.
So many re-hashes of the same subject. Higher octane equated to gasoline MPG without the consideration of the ethanol blend. So much misunderstanding of what 'octane' really means summated with a subjective numerical answer.
How many times are we going to repeat them? "One more time." Repeat.
87 Mid-grade/Plus/Zoom Zoom from a Top Tier vendor, or 91 Premium/Zoom Zoom Zoom for about the same price at Costco. Colorado Costcos carry 85 Regular and 91 Premium.
Agree.
I used to get a bit bugged by so many repeat questions on other forums (automotive, solar etc) when a simple search of the term would bring it all up however it's just too easy to type a question and post it. Once I made a comment about the issue, a moderator replied and said that the purpose of the forum was education so I guess "bring it on".
It is a bit confusing though with octane, E-10 and E-15 or E-85 fuel, the effects of altitude and all. Back in the day' you listened for the "pinging" and then either (manually) retarded the timing or stepped up in octane. Haven't been doing that for decades now!
As ethanol use and % increases, there may be more concerns over what the increased percentage of ethanol is doing to the fuel systems and longevity.
I haven't really read this link but it sounds interesting:
Ethanol and Octane For Beginners
https://mnbiofuels.org › media-mba › blog › item › 1511-octane-and-ethan
Anyway, I use 87/89 as I see it available. When at Costco, it's cheaper fuel so I throw in some 91 (1/2 tank) at times. I try to avoid 85 if at all possible, since our hemi's are rated for 89 I think. There's those who swear it 1 - makes no difference or 2 - gives them better mileage and more power. Since there are so many variables between tanks, I don't see how the average user would be able to really tell (scientifically). When I drive the same route the same way daily, and get 2-4 mpg difference in average mileage over a tank, I have to wonder if it's octane, water or other impurities in the fuel or what...