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Expected MPG: 6.4/3.73

Very interesting experiment Gondul, nice to know that gas is accessible if needed. I'm disappointed that I can't improve the DTE accuracy using AlfaOBD. It's already defaulted to the minimum.

I was under my truck today and I looked at the fuel tank. There's a big empty space in front of the fuel tank on the mega cab. It would have been no problem to put in a longer tank. 40 gallons at least. Sure wish that was an option.
 
Gondul said:
FWIW...

Ran the truck until the "LOW" indicator showed up on the DTE Dial.
Drove another 40-ish miles before I ran out of gas... there was no sputtering or warning, it simple stopped running.
Waited 30 seconds or so and then hit the 'Start' button again... all it did was crank and did not fire up.

I put in 5 gallons out of the can I brought with me for this purpose and the truck started right up.
It was then a 2 mile drive to the gas station where I added 25.88 gallons of gas.

So 410-ish miles at 13-ish mpgs is when I ran out of gas.
Mostly home to work mileage (30 miles round trip surface/highway is 50/50)
Click to expand...
Thanks for sharing the feedback. No more messing around when the DTE light comes on, I’m heading for the pumps !!
 
Gondul said:
FWIW...

Ran the truck until the "LOW" indicator showed up on the DTE Dial.
Drove another 40-ish miles before I ran out of gas... there was no sputtering or warning, it simple stopped running.
Waited 30 seconds or so and then hit the 'Start' button again... all it did was crank and did not fire up.

I put in 5 gallons out of the can I brought with me for this purpose and the truck started right up.
It was then a 2 mile drive to the gas station where I added 25.88 gallons of gas.

So 410-ish miles at 13-ish mpgs is when I ran out of gas.
Mostly home to work mileage (30 miles round trip surface/highway is 50/50)
Click to expand...
Thanks for taking one for the team lol
 
Looks like the Fuelly website has hundreds of thousands of miles of combined real world hand calculations now, and regardless of model year the 6.4L trucks are dead nuts consistent at 12 MPG average.

That's pretty damned miserable, but then again it's a 7,000 lb. vehicle with a large displacement V8. On the other hand, if you factor in maintenance and upfront costs for the Cummins, the Hemi ends up saving money over 10 years of ownership.
 
WXman said:
Looks like the Fuelly website has hundreds of thousands of miles of combined real world hand calculations now, and regardless of model year the 6.4L trucks are dead nuts consistent at 12 MPG average.
Click to expand...

If that's miserable, I'd love to have that misery. :D
 
I got 16.24 hand calculated on the 435 mile trip home from the dealership this past weekend. About 90% of those miles were freeway. Probably 30-40 of those freeway miles were "slow and go", with the rest at about 70mph. At a constant 70mph it was getting about 17.5-18mpg.
2021 3500 4x4 cc 6.4 gas 3.73's.
 
just James said:
I got 16.24 hand calculated on the 435 mile trip home from the dealership this past weekend. About 90% of those miles were freeway. Probably 30-40 of those freeway miles were "slow and go", with the rest at about 70mph. At a constant 70mph it was getting about 17.5-18mpg.
2021 3500 4x4 cc 6.4 gas 3.73's.
Click to expand...

Thats not bad. Similar to what many cummins trucks do TBH.

The around-town stuff is what kills MPG, diesel or gas.
 
I am seeing just over 12 out of my 6.4/3.73 combo with just over 500 miles on it. Very little highway and lots of stop and gulp.

Sent from my moto z3 using Tapatalk
 
Had to run out to western NE to look at a job yesterday and decided to take personal truck just to see what a longer empty trip would do.
Trip out was roughly 120 miles of 2 lane, cruise set at 69, hilly drive - no mountains but hilly for North central Nebraska - then 122 miles westbound I-80 which is mostly flat but a steady climb in elevation the whole way. Return trip was exact same trip in reverse. Rest of miles were in towns, a couple drive thru's for food and a little time on a job site.
Reset trip odometer when I left gas station in home town, put in 10.0 gallons on the way home and filled up at same station in home town about 2 miles after last picture. Hand calculated over the entire 538 miles was 16.6. Not going to complain about this at all. Just a tick over 3500 total miles on truck.

20210601_084131.jpg20210601_134340.jpg20210601_183309.jpg
 
They don't do bad until you hook something to them. Then it drops like a rock. I lose 3-4 pulling my boat and my 29' enclosed hauler cuts it by about 1/2. I get 7-8 pulling that at 70 MPH no matter if it's loaded or empty.
 
How accurate are those numbers coming off the dash? In the early years of development the DTE and Average MPG was a joke coming off the dash. Considering they are accurate, my dash numbers with my 6.7 w/ 3.73r, 21.2 average mpg unloaded and - ready for this(?) - 10.0 average mpg pulling around 10,000#. I am ok with this, as long as the greed that dispenses fuel stays within limits! Right now, it's teetering.
 
Accuracy still seems to be hit/miss... mine is optimistic by 1-2 mpg.
I simply ignore it and just hand calculate to get several averages based on what I'm doing (city/highway/towing)
 
I use an app. I put mileage, gallons, etc in and it tracks MPG and costs over time.
 
RAM_Dad said:
I use an app. I put mileage, gallons, etc in and it tracks MPG and costs over time.
Click to expand...

I use Fuelly, it is good for an overall average, but I still need to know an average for specific scenarios.
 
2500 miles-ish and getting 11-12. Almost zero highway explains that.

Sent from my moto z3 using Tapatalk
 
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