7.3l Godzilla w/10 speed MPG

I had 15.6 mpg once for a few hundred miles but that turned out to be a hoax in the long run and made me feel bad ever after having boasted about it on this forum. I’m more in the range of others here:
- 11.8 mpg passionate suburban driving
- 13.5 babying it
- Can get over 14 in highway miles
 
Got 12.5 on my very first tank. Doing the next one in eco mode to compare.
This is what I’m interested in most. I wonder if eco can give another mpg stop light to stop light if you aren’t heavy footed? Surely it would benefit highway mpgs, I’m curious about around town. Anyone use eco extensively or exclusively around town between stop lights?
 
This is what I’m interested in most. I wonder if eco can give another mpg stop light to stop light if you aren’t heavy footed? Surely it would benefit highway mpgs, I’m curious about around town. Anyone use eco extensively or exclusively around town between stop lights?
Eco mode turns the truck into a limp dick with no improvement in mileage.
 
Picked up today with 6 miles. Did 633 on Fwy towards home in Eco mode and 12.9 is the average. Average speed was 80
So, second half home today. Total 1093 miles, 98% Freeway 70-85 MPH in Eco and average 12.9 mph for the trip.

PS: lowered tire pressure this am before starting home, 55 front and 69 rear, drives way better.
 
I just got back from going from 100ft elevation to 7200 at donner summit traveling 70-75mph. Got 13mpg. Very impressed. 200 mile trip uphill.
Dude heck yea! I do the same drive but opposite direction from 5k-7200 and above depending on where around the lake. Stoked to get my 7.3. I’ve taken my tundra on the same route coming back from SF, and I can guarantee you this 5.7 with the 6 speed has never seen above 13mpg ever.
 
Dude heck yea! I do the same drive but opposite direction from 5k-7200 and above depending on where around the lake. Stoked to get my 7.3. I’ve taken my tundra on the same route coming back from SF, and I can guarantee you this 5.7 with the 6 speed has never seen above 13mpg ever.
Round trip Sonoma county to Reno and back was just over 14mpg.

I will say once over 75-80 mph mpg downgrades quickly. My trip up to redbluff slight uphill at near 80 was closer to 12mpg.
 
Mostly traveling light in normal mode. I have a 14k dump trailer I tow occasionally. Also tow various boats across town as needed. Love this truck and this motor!
 

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Averaging right at 11.0 mpg with our 4 Wheel Camper. Stock Wheels, Tires, Suspension.
Recent trip to Big Bend National Park - Drove 80 mph on I-10, 75 on secondary highways, about 110 miles on the backroads at 10 to to 25 mph. Overall average was 10.8 mpg for 1,100 miles.View attachment 12822
I'm happy - we switched from a 2008 6.4L 2WD F-250 that also averaged about 11.0.
The Tremor drives and handles great on pavement and on the 4x4 roads.
Is that an FWC Hawk shell or loaded? I have a 2014 on a '13 Silverado 2500HD Duramax and I am contemplating the Tremor. Million dollar question is gas or diesel. My duramax is tuned and gets great mileage so I am running the numbers and driving myself crazy, lol.
 
Averaging right at 11.0 mpg with our 4 Wheel Camper. Stock Wheels, Tires, Suspension.
Recent trip to Big Bend National Park - Drove 80 mph on I-10, 75 on secondary highways, about 110 miles on the backroads at 10 to to 25 mph. Overall average was 10.8 mpg for 1,100 miles.View attachment 12822
I'm happy - we switched from a 2008 6.4L 2WD F-250 that also averaged about 11.0.
The Tremor drives and handles great on pavement and on the 4x4 roads.
I’m getting the same with my rack and roof top tent.
 
8-9 towing
11.5 City
13 Hwy
I have 2200 miles with enough of all 3 types of driving to have an accurate idea. I don't hot rod around and probably get about as good a mileage as you can. Cruise 70mph, easy off the line, etc.
That’s about all my 2019 Duramax w/ a 6-speed tranny, 35 inch tires, and 4.56 ring & pinions got for fuel mileage.

Honestly, if I don’t have to put up with adding DEF fluid, the DPF eventually plugging, and constantly worrying about losing an injector … I don’t care what kind of fuel mileage it gets !!! LOL
 
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Mile mileage to date. Trying e15 this tank to see if I get any difference in mileage. It’s .10 cheaper per gallon. Ultimately I’m not too concerned with mileage but like to track it. I plan on writing a web app when I get time so it’s easier to track than in notes. Well it’ll be a full maintenance tracker.


Tank2

July 7 2021

Tank start

225.7 miles

Tank end

500.4 miles

22.117 gallons 87 E10

$63.90

$2.889 per gallon

274.7 miles on tank

12.42 hand 13.0 display



Tank 3

July 23 2021

Tank start

500.4

Tank end

727.0

227 miles on tank

19.403 gallons e10

$54.50 @ $2.809

12.2 display 11.7 hand



Tank 4

Tank start

727.0

Tank end

986.0

259 miles on tank

23.037 gallons e15

$64.94 @ $2.819

11.26 hand 11.5 display

140 miles towing 24’ flatbed 70 miles with 75 f250 highboy loaded.
 
That’s about all my 2019 Duramax w/ a 6-speed tranny, 35 inch tires, and 4.56 ring & pinions got for fuel mileage.

Honestly, if I don’t have to put up with adding DEF fluid, the DPF eventually plugging, and constantly worrying about losing an injector … I don’t care what kind of fuel mileage it gets !!! LOL
My 19 duramax was awful on fuel. Especially towing. I get 1 mpg less towing with my 7.3 then my dmax got
 
Averaging 13.0 unloaded.
Just hauled a 68 camaro on a 20ft dovetail and averaged 11.5.

same style driving loaded unloaded. Pretty pleased with the loaded mileage.
 
Screen shot below of trip going to Mt Rushmore from Auburn CA. I'm on the return in Salt Lake now. Towing a 36 ft Montana. The scale sheet is minus me, missus and kid so add another 500 lbs to the truck.
20210731_170530.jpg
20210731_170606.jpg
 
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