Is Higher Octane Better
Moderator
Joined: May 2004
Posts: 6,512
Likes: 905
From: Home Base Nebraska
Denny
Tuned
Joined: Feb 2009
Posts: 400
Likes: 25
From: Queen Creek
Your manual also recommends 91 or better octane for 'best performance' when towing or in hot weather. Just follow what your manual recommends and don't overthink it. Agree with others...nothing less than 87.......
Laughing Gas
Joined: Nov 2010
Posts: 790
Likes: 254
Trending Topics
Postmaster
Joined: Jul 2015
Posts: 4,392
Likes: 22
From: very South Texas
READ and or search..
< google > why 85 octane in the mountains.
here is 2
https://tap.fremontmotors.com/truste...se-at-altitude
https://www.quora.com/Why-is-regular...ion-U-S-states
< google > why 85 octane in the mountains.
here is 2
https://tap.fremontmotors.com/truste...se-at-altitude
https://www.quora.com/Why-is-regular...ion-U-S-states
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Top 10 Ford Trucks Coming to Mecum Indy 2026
Brett Foote
5 Best / 5 Worst Ford Truck Wheels of All Time
Joe Kucinski
Laughing Gas
Joined: Oct 2017
Posts: 922
Likes: 7
What the manual states for using at higher altitude to use HIGHER octane gas doesn't make any sense. Perhaps they assume you are towing/going up hill a lot.
Whatever it is, I've used 85 in many cars at high altitude and it's been fine.
Logistics Pro
Joined: Apr 2000
Posts: 4,334
Likes: 306
From: Mills River
Ford began including the higher AKI recommendation for “best performance” for MY2017 when they introduced the improved 6.2.
I’ve not seen any recommendation to use “higher AKI fuel at higher elevations”.
HTH,
Jim / crewzer
Cargo Master
Joined: Jan 2004
Posts: 2,422
Likes: 696
From: Minnesota
READ and or search..
< google > why 85 octane in the mountains.
here is 2
https://tap.fremontmotors.com/truste...se-at-altitude
https://www.quora.com/Why-is-regular...ion-U-S-states
< google > why 85 octane in the mountains.
here is 2
https://tap.fremontmotors.com/truste...se-at-altitude
https://www.quora.com/Why-is-regular...ion-U-S-states
Is 85 Octane Ok To Use At Altitude?
It seems there is not a definitive answer to this as far as modern vehicles go (anything without a carburetor).The EPA says on their website, “The sale of 85 octane fuel was originally allowed in high-elevation regions—where the barometric pressure is lower—because it was cheaper and because most carbureted engines tolerated it fairly well. This is not true for modern gasoline engines. So, unless you have an older vehicle with a carbureted engine, you should use the manufacturer-recommended fuel for your vehicle, even where 85 octane fuel is available”.
85 Octane is old school . . . . Ford says never use less than 87 octane.
Laughing Gas
Joined: Oct 2017
Posts: 922
Likes: 7
And using information out of the link you provided . . .
The EPA says on their website, “The sale of 85 octane fuel was originally allowed in high-elevation regions—where the barometric pressure is lower—because it was cheaper and because most carbureted engines tolerated it fairly well. This is not true for modern gasoline engines. So, unless you have an older vehicle with a carbureted engine, you should use the manufacturer-recommended fuel for your vehicle, even where 85 octane fuel is available”.
85 Octane is old school . . . . Ford says never use less than 87 octane.
Is 85 Octane Ok To Use At Altitude?
It seems there is not a definitive answer to this as far as modern vehicles go (anything without a carburetor).The EPA says on their website, “The sale of 85 octane fuel was originally allowed in high-elevation regions—where the barometric pressure is lower—because it was cheaper and because most carbureted engines tolerated it fairly well. This is not true for modern gasoline engines. So, unless you have an older vehicle with a carbureted engine, you should use the manufacturer-recommended fuel for your vehicle, even where 85 octane fuel is available”.
85 Octane is old school . . . . Ford says never use less than 87 octane.
Logistics Pro
Joined: Apr 2000
Posts: 4,334
Likes: 306
From: Mills River
Modern engines will likely retard ignition timing to compensate for low AKI fuel, and the engine will probably appear to operate without issue. However, power and fuel economy will likely suffer.
HTH,
Jim / crewzer
HTH,
Jim / crewzer
Laughing Gas
Joined: Oct 2017
Posts: 922
Likes: 7
I'm sure they do, on top of the hit for the altitude. Used to drive s stick shift na car. Absolute dog at this altitude. Now have a turbocharged car which is night and day.