93 vs 87 Octane in 2.3L with Manual Transmission

ChetC

Jul 02, 2022

I have logged my MPG for almost 10,000 miles now calculating mileage on Fulley.com, which translates to 41 tanks of gas in my 2-door Big Bend. I travel and work from the road towing a small 1500 lb camper. I had used nothing but 93 octane up until June 23 when I decided to compare mileage and power with a switch to 87 octane for a few tanks. Below is a chart showing the comparison between 87/93 over seven tanks of gas each. Again, this is towing a 1500 lb camper across the midwest and east coast.

Screen Shot 2022-07-02 at 11.23.31 AM.png

I don't run the Bronco hard, rarely exceeding 3,000 rpm, set the cruise on the speed limit and tow in 5th gear at highway speeds (2,500 rpm at 70 mph). I found I get better MPG this way as it stays out of the turbo. If you tow in 6th it will still pull the speeds but it has to ramp up the boost. As you can see, I've had minimal impact on my MPG and I have had no discernible loss of power. In other words, I can't tell the difference between 87 and 93 octane when I'm towing, it feels the same either way and pulls the hills in the Appalachians the same way at the same speed. I'm not hearing any detonation and the operating temperatures remain the same.

Make of this what you will but for me I'm running 87 octane from here on out.

Crawler Green, Deano Bronc

Last edited by a moderator: Jul 02, 2022

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Jul 02, 2022

Nice work up and thanks for sharing. I’m too poor to run anything other than 87 right now anyways tho lol

2022 Big Bend, 4 door, Cactus Grey, on 285/70/17 KO2s

Poindexter_d

Jul 02, 2022

Agree, thank you for sharing. I was planning to run 93, but with your real world data, not sure I see a reason to know.

ChetC

Jul 02, 2022

ChetC
I have logged my MPG for almost 10,000 miles now calculating mileage on Fulley.com, which translates to 41 tanks of gas in my 2-door Big Bend. I travel and work from the road towing a small 1500 lb camper. I had used nothing but 93 octane up until June 23 when I decided to compare mileage and power with a switch to 87 octane for a few tanks. Below is a chart showing the comparison between 87/93 over seven tanks of gas each. Again, this is towing a 1500 lb camper across the midwest and east coast.

View attachment 38948

I don't run the Bronco hard, rarely exceeding 3,000 rpm, set the cruise on the speed limit and tow in 5th gear at highway speeds (2,500 rpm at 70 mph). I found I get better MPG this way as it stays out of the turbo. If you tow in 6th it will still pull the speeds but it has to ramp up the boost. As you can see, I've had minimal impact on my MPG and I have had no discernible loss of power. In other words, I can't tell the difference between 87 and 93 octane when I'm towing, it feels the same either way and pulls the hills in the Appalachians the same way at the same speed. I'm not hearing any detonation and the operating temperatures remain the same.

Make of this what you will but for me I'm running 87 octane from here on out.

Yeah the 87 is the way to go. Run a tank of 93 every once in a while to burn out the cylinders, but why pay more if it’s not gaining anything ?

2Dr Badlands, manual, 322A, Iconic Silver, baby seal leather seat covers, reserved 2-24-22, stickered/blend date 9/30/22

thgdfathr, ChetC

Jul 02, 2022

Interesting data. I have a 2 door Black Diamond, 2.3L engine and manual transmission. Running 91 octane I get 23 mpg.

Jul 02, 2022

jtpasto
Interesting data. I have a 2 door Black Diamond, 2.3L engine and manual transmission. Running 91 octane I get 23 mpg.

That’s a pretty difference between the two posts. Driving habits have to account for some of that , slow vs fast starts, and a heavier foot maybe ?

2Dr Badlands, manual, 322A, Iconic Silver, baby seal leather seat covers, reserved 2-24-22, stickered/blend date 9/30/22

Jul 02, 2022

jtpasto
Interesting data. I have a 2 door Black Diamond, 2.3L engine and manual transmission. Running 91 octane I get 23 mpg.

Again, just to clarify what I posted, these numbers are pulling a 1500 lb travel trailer. I can easily surpass 22 MPG without the trailer as well.

Jul 02, 2022

Thats interesting. I've done the same type of comparison on my Focus and going from 87 to 93 the mileage increases 1.75 mpg. and doesn't ping.Pings on 87.

Jul 02, 2022

Bronco V-8
Thats interesting. I've done the same type of comparison on my Focus and going from 87 to 93 the mileage increases 1.75 mpg. and doesn't ping.Pings on 87.

The Focus has a much different tune than the Bronco though so that makes sense.

Jul 04, 2022

ChetC
I have logged my MPG for almost 10,000 miles now calculating mileage on Fulley.com, which translates to 41 tanks of gas in my 2-door Big Bend. I travel and work from the road towing a small 1500 lb camper. I had used nothing but 93 octane up until June 23 when I decided to compare mileage and power with a switch to 87 octane for a few tanks. Below is a chart showing the comparison between 87/93 over seven tanks of gas each. Again, this is towing a 1500 lb camper across the midwest and east coast.

View attachment 38948

I don't run the Bronco hard, rarely exceeding 3,000 rpm, set the cruise on the speed limit and tow in 5th gear at highway speeds (2,500 rpm at 70 mph). I found I get better MPG this way as it stays out of the turbo. If you tow in 6th it will still pull the speeds but it has to ramp up the boost. As you can see, I've had minimal impact on my MPG and I have had no discernible loss of power. In other words, I can't tell the difference between 87 and 93 octane when I'm towing, it feels the same either way and pulls the hills in the Appalachians the same way at the same speed. I'm not hearing any detonation and the operating temperatures remain the same.

Make of this what you will but for me I'm running 87 octane from here on out.

I've read and done the same over the years. Back in the 90's towing a 25' boat with my 95 Suburban, etc. My 2017 F-150, 3.5 dual turbo is the same. I've been to AZ, SD, and other trips that 87 works fine, get the same mileage. I drive 65 MPH. My next test will be the 65 vs. 70 MPH difference. WIll try that on a trip to CO this summer. Thanks for posting.

ChetC

Jul 04, 2022

#10

MarkPS
That’s a pretty difference between the two posts. Driving habits have to account for some of that , slow vs fast starts, and a heavier foot maybe ?

I get 23 mpg in a F-150 with 87, at 65 MPH. Not towing. This is a 3.5 dual turbo & 10 speed trans.

Jul 04, 2022

#11

Octane has never been about MPG.
It’s about increasing performance by reducing pre-detonation (“pinging”). Most modern engines will reduce spark advance if they detect pinging, which hurts performance.
But, if you are not racing, it shouldn’t make any significant difference for normal driving.

Nov 08, 2022

#12

MarkPS
That’s a pretty difference between the two posts. Driving habits have to account for some of that , slow vs fast starts, and a heavier foot maybe ?

16.9 here, not hard to tell why for me

2dr Badlands 2.3 Manual w/Mid, Rapid Red
My blog, Mfcomics.net, my stories: https://payhip.com/MFComics

Deano Bronc, Crawler Green

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