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As I understand it, the biggest advantage to higher octane when towing is, better performance and might help engine run cooler. The slight better increase in mpg typically does not offset the stupid increase in price. I simply run mid grade always, top tier and call it a day. Likely wasting a bit of $, what the heck, can't take it with ya.
Too many variables to mean diddly-squat. What is the absolute elevation difference between destinations? Prevailing wind direction and speed? Air temperature? All those make a bigger difference than the octane rating. As @SpencerPJ stated above, Ford recommends using the higher octane for towing to reduce heat stress on your engine and offer a slight increase in performance.
That's about a 9% increase in MPG, but at what % increase in cost per gallon, maybe you have those record details to share, as part of a cost benefit analysis?
High octane also reduced detonation which is more likely while towing in the mountains. For that reason alone I would use premium during mountain towing, other wise 87 or 89 is adequate to me.
On my last long 5000 mile trip (PA to AZ with a 4000# travel trailer), I mostly used 87 regular for the first half. Once I was in an area where gas prices were a bit lower, I basically alternated fillups 87 & 91/92 premium. I got about 8.5 MPG on 87 going out and 11 MPG on the mixed return, until I no longer gaged on the price. So an almost 30% MPG gain was worth it for the most part, especially the distance traveled between fuel fillups with just a 26 gallon tank.
The area where the gas was more reasonably priced was mostly less hilly, also making a big difference.
Last edited by Boomerweps; Apr 3, 2026 at 02:39 PM.
That's about a 9% increase in MPG, but at what % increase in cost per gallon, maybe you have those record details to share, as part of a cost benefit analysis?
High octane also reduced detonation which is more likely while towing in the mountains. For that reason alone I would use premium during mountain towing, other wise 87 or 89 is adequate to me.
For the $$ to make sense, the difference has to be .45c or less.
For the $$ to make sense, the difference has to be .45c or less.
What was that saying back in school, show your work please.
There is more than one way to do this comparison. Here's my approach, from a Google search: premium costs roughly 70–90 cents more per gallon, using a round figure of $5/gal. and the 90 cent that's a 18% fuel cost increase, so the % MPG gained by premium fuel would have to exceed 18% fuel cost increase.
2008__XL how much more it the 91 non ethanol you mentioned than regular? I have read that 15% ethanol is being considered recently due to fuel costs, even though Corn Ethanol EROI (Energy Return On Investment): Studies show a narrow positive return, frequently quoted around 1.2 to 1.6, while some older studies showed near break-even (1:1). Thus a Midwest farm subsidy, to me the extra corn should be sold to other counties, keeping ethanol out of our gas.
93 vs 87
