85 vs 87 Octane at Elevation

[Gardnetm]

In Salt Lake City and surrounding areas, our regular gas is 85 octane, not the 87 that the maverick manual recommends. For the AWD Ecoboost, if you can't hear any knocking, will 85 suffice? I can't believe how divided everyone seems to be on this topic, especially when there seems to be solid science supporting both sides. Seems like elevation (~4500 ft nominally) is a factor and turbo aspiration is another. I'm interested in the short and long term impacts on mpg, horsepower, and overall engine maintenance.

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[FirstOnRaceDay]

Yes always use 87 or better. It will help the longevity in the long run.
id also recommend running premium(91/93) every so often as well

 

[mrjspence]

I’m in CO front range at just over 5,000’ elevation and we have the same lower standard octane system here. I’ve been putting the cheapest Costco fuel in our Maverick and it’s been just fine. I haven’t noticed any difference going anywhere. We also had a 5.4 V8 F150 that for 17 years always got the cheapest lowest grade CO gas (save a few towing trips which I always used premium) and never had any issues with that truck either and that triton engine is known to have lots of issues.
Also in remember the gasoline you put in your car during the winter is not the same as the gasoline you pump during the summer (look up RVP if you’re interested).
I don’t think it matters with regular day-to-day commute style driving but I’m not an expert or a mechanic lol. I’m sure you could get very scientific about this.

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