Colorado octane

[Cartlin]

Hey all,
My Braptor is sitting in Denver where I recently visited. Went to Costco for a fill up and they had two choices: 85 and 93 octane. Never saw 85 before. It was not labeled E85. I ended up mixing the two. I haven't seen this anywhere else and didn't feel good about using the 85 straight.
Any CO owners facing this? The minimum we need is 87, right?

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[MileHighCitizen]

If you look into it, you'll find that because of the lower density of oxygen at altitude, you can run 85 oct. the same as 87. There are a lot of articles on the internet about it if you're curious.

 

[paleh0rse]

Higher altitudes require/sell lower octane fuel. Their 85 octane fuel at 5k+ feet is equivalent to 87 octane at sea level.

That said, I'd personally stick with 90+ octane for max performance in a Braptor, but maybe that's just me...

 

[FJ 432]

I live here as well. 85 Octane is sold in higher elevations only. However, I only use 91.

 

[Cartlin]

If you look into it, you'll find that because of the lower density of oxygen at altitude, you can run 85 oct. the same as 87. There are a lot of articles on the internet about it if you're curious.

Thanks! Learned something new today.

 

[Cartlin]

I live here as well. 85 Octane is sold in higher elevations only. However, I only use 91.

I live at sea level. My Braptor has still never been home. Sitting in Denver until further notice.

 

[Bigave33]

I would run at least 87 octane. If your car has a turbocharger, it is a compressor that will compensate for the lower density of oxygen.

 

[ultimateone]

put 93 in always with a Raptor if you can

 

[MileHighCitizen]

Thanks! Learned something new today.

Common wisdom says to use the highest octane possible in turbo vehicles and most OEMs require it. Ford tunes for different octanes and the computer will account for the changes on the fly, but there is about a 10-15hp difference in the 2.7 when using 91 instead of 87.

https://fordauthority.com/2021/05/2021-ford-bronco-horsepower-torque-ratings-revealed/

Also, I've noticed I get a few more MPG when using 91. Ive only used 87 when filling on a roadtrip because thats all that was available.

 

[bobogto]

A lot of misinformation.
Currently the only reason why in this day and age you would still have (R+M)/2- 85 octane is price. 40 years ago when cars(mostly American) had little to no way of proper controlling ignition and oxygen levels into the engine lower octane would have made sense in a way to control it at high altitudes(lower atmospheric pressure). These days are long gone. Today NA engines are rare and even those have advanced timing capabilities to account for lower atmospheric pressures. The only thing a lower octane will accomplish is higher chance of pre-ignition and pre-detonation. Which is ironic because that's the main reason it was actually implemented in the first place. Also, because I had a huge argument with my wife, I actually read my Maverick owners manual. 2.0L turbo engine. It specifically states to not use lower than 87 octane, specifically for high altitude locations. They know about these places and issued a statement for it.
Bottom line is American vehicles don't have the simple, unsophisticated engines they used to. You need to make sure you use the best oil and fuel possible and ignore the "oh, I've been using peanut oil in mine and it's been fine for 200000 miles already..."
Yes, I do have a 2015 3.5L Twin Turbo F150 at work with 140000 miles that uses only the cheapest fuel possible, the cheapest oil possible, oil changes vary from every 3000 miles to 10000 miles and this thing still runs like a champ. This is the exception to the rule tho.

Here is a passage from the "Bronco" owners manual(all engines):

" Your vehicle operates on regular unleaded gasoline with a minimum pump (R+M)/2 octane rating of 87. Some fuel stations, particularly those in high altitude areas, offer fuels posted as regular unleaded gasoline with an octane rating below 87. The use of these fuels could result in engine damage that will not be covered by the vehicle Warranty. For best overall vehicle and engine performance, premium fuel with an octane rating of 91 or higher is recommended. The performance gained by using premium fuel is most noticeable in hot weather as well as other conditions, for example when towing a trailer. See Towing a Trailer (page 283). "

 

[Cartlin]

A lot of misinformation.
Currently the only reason why in this day and age you would still have (R+M)/2- 85 octane is price. 40 years ago when cars(mostly American) had little to no way of proper controlling ignition and oxygen levels into the engine lower octane would have made sense in a way to control it at high altitudes(lower atmospheric pressure). These days are long gone. Today NA engines are rare and even those have advanced timing capabilities to account for lower atmospheric pressures. The only thing a lower octane will accomplish is higher chance of pre-ignition and pre-detonation. Which is ironic because that's the main reason it was actually implemented in the first place. Also, because I had a huge argument with my wife, I actually read my Maverick owners manual. 2.0L turbo engine. It specifically states to not use lower than 87 octane, specifically for high altitude locations. They know about these places and issued a statement for it.
Bottom line is American vehicles don't have the simple, unsophisticated engines they used to. You need to make sure you use the best oil and fuel possible and ignore the "oh, I've been using peanut oil in mine and it's been fine for 200000 miles already..."
Yes, I do have a 2015 3.5L Twin Turbo F150 at work with 140000 miles that uses only the cheapest fuel possible, the cheapest oil possible, oil changes vary from every 3000 miles to 10000 miles and this thing still runs like a champ. This is the exception to the rule tho.

Here is a passage from the "Bronco" owners manual(all engines):

" Your vehicle operates on regular unleaded gasoline with a minimum pump (R+M)/2 octane rating of 87. Some fuel stations, particularly those in high altitude areas, offer fuels posted as regular unleaded gasoline with an octane rating below 87. The use of these fuels could result in engine damage that will not be covered by the vehicle Warranty. For best overall vehicle and engine performance, premium fuel with an octane rating of 91 or higher is recommended. The performance gained by using premium fuel is most noticeable in hot weather as well as other conditions, for example when towing a trailer. See Towing a Trailer (page 283). "

This is great info! I'm glad I at least mixed to get somewhere above 87 but based on the manual excerpt I'll be using 91 or better.

 

[userdude]

oh, I've been using peanut oil in mine and it's been fine for 200000 miles already...

I use a peanut/avocado blend.

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