Differences in Octane

[Jacob]

Okay damndest thing I’ve noticed. So I’ve been running 91 octane since I bought my 2019 in December. Decided to switch to 89 to save a little bit of coin and son of a gun my MPG went from 20.9 to 23.8.

now I have never really believed in the differences in octane unless your vehicle required premium. I’m puzzled by this. I don’t get how it would improve by that much. Can someone explain because I quite frankly can’t believe this.

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[Lunchbox88]

Okay damndest thing I’ve noticed. So I’ve been running 91 octane since I bought my 2019 in December. Decided to switch to 89 to save a little bit of coin and son of a gun my MPG went from 20.9 to 23.8.

now I have never really believed in the differences in octane unless your vehicle required premium. I’m puzzled by this. I don’t get how it would improve by that much. Can someone explain because I quite frankly can’t believe this.

In reality it shouldnt make that much of a difference. Probably just differences in your driving/traffic/stop and go/passing/towing/hills ect.

 

[Jacob]

In reality it shouldnt make that much of a difference. Probably just differences in your driving/traffic/stop and go/passing/towing/hills ect.

Driving patterns haven’t changed at all. Still making the same trips up and down the foothills and consistent three days of in town driving. I thought maybe the sensor that reads it

 

[Ace Holliday]

Okay damndest thing I’ve noticed. So I’ve been running 91 octane since I bought my 2019 in December. Decided to switch to 89 to save a little bit of coin and son of a gun my MPG went from 20.9 to 23.8.

now I have never really believed in the differences in octane unless your vehicle required premium. I’m puzzled by this. I don’t get how it would improve by that much. Can someone explain because I quite frankly can’t believe this.

You really can't go by one tank of gas. It requires more data to be an accurate analysis.

 

[caprtaineddie]

Could the change be attributed to a change in operating temperatures? It's warmer now.

 

[Lunchbox88]

Could the change be attributed to a change in operating temperatures? It's warmer now.

Reminds me that summer blends of gasoline will be slightly better than winter

 

[Jacob]

You really can't go by one tank of gas. It requires more data to be an accurate analysis.

This would be take number 8 or 9 actually

 

[Jacob]

Reminds me that summer blends of gasoline will be slightly better than winter

Hmmm perhaps, at this point I have no clue

 

[Racket]

Are you using the onboard computer or calculating by hand? I found my as-delivered Ranger's mileage was not displaying accurately.

Ultimately had to go into 'Engineering Mide' and change some settings to make it match manual calculating mileage.

I too run mid-grade because Ethanol-added 87 did not run well at lower speeds in city driving. Easy to find 89 with 91 being less common and those run good. The mileage increase hasn't been a money saver over 87 for the cist difference but I can't justify high-octane prices. I found ethanol-free 87 and it cost nearly what high octane did - though the ethanol-free ran well.

Now, E15 comes in 88 octane and by itself seemed a little down on power off the mark, but the turbo seemed to like it. Gas mileage was the wirst. I splurged on topping off half a tank of that with premium and I felt the truck performed really well, but I'm not going to do that all the time.

 

[aeroshots]

2.9 mpg increase and cheaper fuel. Wow that's crazy.

 

[Speedwagon]

Okay damndest thing I’ve noticed. So I’ve been running 91 octane since I bought my 2019 in December. Decided to switch to 89 to save a little bit of coin and son of a gun my MPG went from 20.9 to 23.8.

now I have never really believed in the differences in octane unless your vehicle required premium. I’m puzzled by this. I don’t get how it would improve by that much. Can someone explain because I quite frankly can’t believe this.

Depending on where you are, and what they do there: Sometimes the different octanes have different ethanol content. Ethanol is an octane booster, so often higher octanes can have ethanol, while a lower octane might not. And this could account for what you have seen.

I've seen the opposite in my Fiesta ST. I get 35-37mpg highway, on 91 octane. I've gotten 33-35 running lower octanes before.

 

[Jacob]

I haven’t ran 87 yet but I feel that I should try it now and see what happens to my MPG. At the same time, I’m going to manually calculate my mileage as well to see if maybe the computer is just off

 

[GTGallop]

Octane is the measure of resistance to burning - not the amount of power in the gas.
Gas that has a lower octane will ignite and burn more cleanly giving you access to the power within in that gas. Too low and it pre-detonates (knock) and you lose power.

You should always use the LOWEST possible octane you can get away with that doesn't cause knock. Our direct injection engines are much less succeptible to knock because of the DI feature and that allows you to get a good clean burn on low-o fuel.

 

[Jacob]

So ran the numbers and the 89 was truly only getting me 22.6 mpg. Nice try ford engineers telling me I’m getting 23 pssshh.

I’m going to try 87 now and see if it changes

 

[wolfhawk73]

Okay damndest thing I’ve noticed. So I’ve been running 91 octane since I bought my 2019 in December. Decided to switch to 89 to save a little bit of coin and son of a gun my MPG went from 20.9 to 23.8.

Years before the ethanol mandate I remember reading an article in one of the big three car mags about this. (I'm not sure how ethanol affects mileage across octane ratings). Lower octane gas generally has more energy per gallon, so an engine could theoretically get better mileage, because it didn't use as much fuel/mile. Higher octane fuels have additives to avoid pre-ignition/spark knock, and those additives actually decrease the total amount of energy per gallon. That was back in the day when cars didn't have all of the knock sensors and uber-computer controls and sensors making sure the engine was running at its most efficient. The new Ranger can most likely sense the difference and run accordingly. It also knows that it can pump more fuel into the cylinders with 93 (decreases pre-ignition), hence the increase in power we've seen in these trucks with higher octane fuels.

I have a 1998 Ranger 4x4 with the 4.0. I currently get about 16 mpg on 87. It goes to 14 mpg on 93, and it does not run nearly as well (SOTP meter).

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