Here is an interesting note. After driving across Montana many times over the years, I realized a few years back that their "regular" gas was as low as 83 octane. For the longest time I spend the extra $ and bought the mid grade that was 87 on the theory that it was better. I realized that after several trips lately, buying the 83 resulted in DRAMATICLLY better mileage. This in spite of the fact that in Montana you are dealing with higher elevations, mountain passes etc. I chalk this up to the fact that lower octane fuel has MORE btu's per given volume than higher octanes. I would like to hear other peoples opinion. Icarus
Absolutely correct! In fact, I've been thinking about an endurance test and I would like to get some 'high plains', 83 octane, non-ethanol gas in some 10 gallon containers and bring them back to Huntsville. Although I'd like to run my endurance test at high altitude, my wife would prefer me to be 'home' instead of driving circles out west. Bob Wilson
Very interesting. I've read here that higher octane can lower your MPG, but I'd never have thought that lower octane can INCREASE your MPG !! So where do I buy "octane reducer" ? Can I sell some octane to sports car drivers and plane pilots ?
Don't know where you got your information. Here is what the Montana Dept. of Weights and Measures says. "While the minimum antiknock rating in Montana is 85.5 for regular unleaded fuel, that is not necessarily what is found. Due primarily to competition and/or multiple suppliers of refined products, regular unleaded gasoline found in Western and Northeastern Montana usually has an octane rating of around 87.0. Central and Southern Montana's fuel octane rating is generally found to be between 85.5 and 86.0 ". Their site is: Montana DLI - Weights and Measures
I've lived in Montana almost my entire life (age 58) and cannot recall ever seeing 83 octane gas offered for sale. 85.5 is the lowest I've seen, and that is very infrequent. Most stations have 87 as "regular". Where did you find 83 octane gas???
To all the sharp knifes in the drawer. I think I had a senior moment. I believe Dave is right and that the lowest octane is ~85 in Montana NOT 83 as I stated earlier....My bad, my bad memory. My statement is still correct, that I get much better mileage with the LOWER octane. Most "regular" around the country is ~ 87. Montana tends to be ~85. Sorry for creating such a negative buzz. Icarus Ps. Traveling most of the east/west corridors, HWY 2 HWY 200 HWY12 I90-94. I have seen it all over the place. If latest faulty memory serves I've seen it as much at Cenex co-ops as often as not, but not only there.
I wonder if it is really low octane or the lack of ethanol that makes your mileage better? Evidently E-10 is not yet required in Montana, though it is available in some areas.
I'm in Denver and I buy 85, nothing else. I've never seen 83 in MT. I get regular when I'm up there, but I don't remember if I was getting 86 or 87.
