How to get better gas mileage from the 7.3?

Red Forman

Tremor Fiend
Joined
May 28, 2020
Messages
374
Reaction Points
831
Location
Texas
We have a 2021 F350 Tremor 7.3L. I see every posting their high MPG. We usually run on a good day. 13.4 anyone else out there run the same or better. Trying g to figure out if there’s something wrong. It might be our driving but usually stay within the speed limit.
40,000 miles on my 2020 and lifetime mileage is 13.2.
 

sonnyd1974

Tremor Fan
Joined
Jan 3, 2022
Messages
34
Reaction Points
30
Location
Weatherford Tx
Current Ride
2022 F250 Tremor 7.3L
Lighter wheels, tires, skinnier tires, drive in a way conducive to using less gasoline. Other than this tuning, I believe 5 star tuning had a tune that should give some mileage, or at least power back. The problem with this is it'll probably void the warranty. Another option that may help is different fuel, 87 octane without ethanol, although this costs more per gallon. Somewhat difficult to increase the mileage in these things as like you said they're already huge/heavy.
My 5 star tune did nothing at all for me. The only positive is the towing shift pattern is a lot better.
 

Explorerinil

Tremor Fiend
Joined
Jun 30, 2022
Messages
460
Reaction Points
621
Location
Illinois
Current Ride
2021 F250 Tremor 7.3
First Responder
Police
So I just went on vacation, 3 people in the truck, light amount of gear. My goal was to get the best fuel economy I can get out of the truck. I drove in eco mode the entire way, lightly accelerating and driving 69 mph max and behind semis the entire way. I hand calculated 17mpg on the highway. My trip computer was close.
846EDB06-90A8-4F00-AE21-0889D316FB3A.jpeg
 

weatherherk

Tremor Fiend
Joined
Nov 10, 2021
Messages
479
Reaction Points
483
Location
Biloxi, Ms
Military
Air Force
Current Ride
2022 F 250 Tremor 7.3
Other than an occasional K&N filter change I’ve always left my trucks stock. I’ve also only had F150’s.
Any ideas on how to improve gas mileage on the 7.3? I know it’s a super duty and you don’t buy them for the gas efficiency. I’m just looking for a few suggestions that may allow me to squeeze out a couple more MPG’s (other than driving in ECO below 65mph!)
so....kinda mess around with this some just because and this is what i came up with. Yes i dropped in a K&N filter and installed a exhaust ....on the interstate i set the speed on 78 and go to ECO mode.....mileage went to 15.5 or so...throttle response was good as needed to pass. i'm pretty much good with that....if i need more spice in the gumbo then back to normal i go. ....works for me
 

Andrewm

Tremor Fiend
Joined
Aug 9, 2021
Messages
477
Reaction Points
942
Location
Moyock
Current Ride
Tesla
So I just went on vacation, 3 people in the truck, light amount of gear. My goal was to get the best fuel economy I can get out of the truck. I drove in eco mode the entire way, lightly accelerating and driving 69 mph max and behind semis the entire way. I hand calculated 17mpg on the highway. My trip computer was close.View attachment 61341
What was the history like?
 

BUFORD

Tremor Buff
Joined
Dec 13, 2021
Messages
92
Reaction Points
109
Location
Dalton, Ga
Current Ride
F150 ecoboost
So I just went on vacation, 3 people in the truck, light amount of gear. My goal was to get the best fuel economy I can get out of the truck. I drove in eco mode the entire way, lightly accelerating and driving 69 mph max and behind semis the entire way. I hand calculated 17mpg on the highway. My trip computer was close.View attachment 61341
what was the terrain like? Very flat, mountainous, both? Here in North Georgia with a 4.30 rear end you would very get that.
 

BUFORD

Tremor Buff
Joined
Dec 13, 2021
Messages
92
Reaction Points
109
Location
Dalton, Ga
Current Ride
F150 ecoboost
So I just went on vacation, 3 people in the truck, light amount of gear. My goal was to get the best fuel economy I can get out of the truck. I drove in eco mode the entire way, lightly accelerating and driving 69 mph max and behind semis the entire way. I hand calculated 17mpg on the highway. My trip computer was close.View attachment 61341
what was the terrain like? Very flat, mountainous, both? Here in North Georgia with a 4.30 rear end you would never get that.
 

Explorerinil

Tremor Fiend
Joined
Jun 30, 2022
Messages
460
Reaction Points
621
Location
Illinois
Current Ride
2021 F250 Tremor 7.3
First Responder
Police
what was the terrain like? Very flat, mountainous, both? Here in North Georgia with a 4.30 rear end you would never get that.
Flat, I really tried very hard to get that and never went over 69 mph.
 

Andrewm

Tremor Fiend
Joined
Aug 9, 2021
Messages
477
Reaction Points
942
Location
Moyock
Current Ride
Tesla
What do you mean? I filled up when I left and filled up when I arrived and calculated my mileage. Trip computer is close.
If you tap down from the live view, it shows the last 2 or so hours... Not a live view or a freshly reset and quick snap shot of what the truck was saying for a second while going down hill. It's the Internet and I trust nothing
 

number9xd

Tremor Fiend
Joined
Jan 14, 2022
Messages
255
Reaction Points
326
Location
KY
My truck gets good mpg with cruise set at 70mph on the slab. No eco mode or intentional actions taken, just set the cruise at 70 and let it work. Stop & Go around town and idling pulls it down hard tho, mid to high 12’s. I reset Trip 2 every fill up, have never reset Trip 1 to keep that my lifetime #’s, current avg is 12.8

XLT, 7.3, 3.55, with 295/70-18 Defender XLT tires (34.4” tall and light).

Recent trip to Indiana
E5DD5099-4E1C-4938-A990-BE0BA3DDDCF2.jpeg


Return trip home
9ED46474-5BF3-4EAE-871C-41F7658B39C6.jpeg
 
Last edited:

number9xd

Tremor Fiend
Joined
Jan 14, 2022
Messages
255
Reaction Points
326
Location
KY
IMO, from everything I researched and read before ordering my truck, again just my opinion (which means nothing), 3.73 gear is ideal for these trucks.

Below comments are unloaded daily driver duties ONLY. Adding towing into the equation is a larger conversion.

3.55 is little on the high side for daily driver. It takes more throttle to get moving around town which results in lower mpg. Larger and/or heavier tires make it worse. It does really good on the slab at freeway speeds however.

4.30 is too low for daily driver. Takes less throttle to get moving around town, which likely contributes to close mpg results to a 3.55 in those conditions. Larger and/or heavier tires don’t have as much of an impact (to a point). On the slab at freeway speeds, it spins the motor higher rpm which results in lower mpg.

I did a lot of research before ordering and actually changed my order from 3.55 to 4.30 and back to 3.55.

If I had a Tremor, stuck with 4.30 gear, and wanted to get best mpg I could, I’d install the non-Tremor 4x4 air dam, keep factory wheels (or wheels with factory offset), be VERY conscious of wheel/tire weight, and run a light tire with low rolling resistance, and drive like a papaw. If you drive with your toes sticking thru the grille your gonna get poor mpg.
 

jjfred2112

plus ça change, plus c'est la même chose
Joined
Feb 25, 2021
Messages
661
Reaction Points
1,616
Location
Lockhart, TX
Military
Army National Guard
Current Ride
2021 Ford F-250 XLT 7.3L Tremor Package
Current Ride #2
2022 Royal Enfield INT 650
Lol! I kept it at that speed. I watched a YouTube channel and the person who did the video pointed out how rapidly fuel economy drops on the 7.3 at 70 mph and above.
I do the same. My wife hates it, but when I pay for the gas I make the calls.
 

Explorerinil

Tremor Fiend
Joined
Jun 30, 2022
Messages
460
Reaction Points
621
Location
Illinois
Current Ride
2021 F250 Tremor 7.3
First Responder
Police
That's not bad
Thanks for showing me the history I had no clue about that. That’s the best ever mpg I have got and let me be clear I had to work to get and maintain that. I drove mainly behind semis and never went over 69mph.
 

Andrewm

Tremor Fiend
Joined
Aug 9, 2021
Messages
477
Reaction Points
942
Location
Moyock
Current Ride
Tesla
Thanks for showing me the history I had no clue about that. That’s the best ever mpg I have got and let me be clear I had to work to get and maintain that. I drove mainly behind semis and never went over 69mph.
PXL_20220926_043032117.jpg
PXL_20220926_043012418.jpg

Beat I could get going 75-80mph on kinda flat/hills in West Virginia
 
Top