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Expected MPG: 6.4/3.73

Kimo7 said:
Update on my experience. I’ve been driving a different route with a lot less stop and go, the EVIC has improved to 14.4 mpg. I decided to leave Trip Meter A running without resetting to see the long term average from driving it off the lot new BUT I randomly reset Trip Meter B a week or so ago to see what short term trip results were. It was convenient today that they all were within a few tenths of a mpg when the low fuel light came on, the display showed 47 miles to empty. I drove 351 miles between fill ups and it took 26.19 gallons to top it off. That equates to 13.4 mpg when hand calculating. The previous fill up calculation was 12.8 mpg so that’s a .6 improvement over my last update. A small increase but I’ll take it.

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I unfortunately discovered that there is no point in leaving a trip meter going to measure mileage over a long period of time. I had done so and discovered unbelievable results over time. It turns out it only goes back a little and then rolls over the data. Completely worthless. for anything but short term calculations. There is a discussion here somewhere on it. Maybe in this thread. If you want long term data, start a Fuelly account and be religious about keeping it updated. That is something I am incapable of doing.

Edit: Found it. https://hdrams.com/forum/index.php?threads/vehicle-mpg-gauge.1408/page-2#post-15173 Only a 200 mile rolling average. If that is the case it isn't even accurate for a tank of gas (that might explain a lot actually) Totally lame if true. One thing that might explain is why your mileage seems to drop off at an accelerated rate after driving on the highway for a while and then going into city driving. Suppose you drive 200 miles at 17 mpg and then another 150 miles at 11 mpg. You are going to get a very bottom ended result of maybe 12 mpg when in fact you really got closer 15 mpg on the full 350 miles. Someone do the math if you want because that is just wild estimates.
 
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Thanks Brucie. I know the computer calculations are off, this is just the first truck I’ve owned where it was this far off. I’m really concerned over accuracy in fuel consumption especially when I’m hooked up and towing our travel trailer. Compounding issue is there’s also a hidden delta of gas, doing the math on what the EVIC DTE function says when weighed against the actual volume filling up at the pump. I believe it errs in favor of not running out of gas but I don’t have confidence to rely on it. Bottom line is I think the fuel tank is too small for the consumption rate of the vehicle - my opinion. I love the truck and the power of the big Hemi, I just wish they had an option for large tank or a better option for auxiliary tank than something external. My travel plan when towing will be to stop and fuel up every 100 - 150 miles to ensure I’m not going to run out.
 
For the guys who have differences between their displayed and hand-calculated MPG, have you tried adjusting your tire size? I set my tire size with the Rough Country programmer to true the speedometer and my displayed MPG is pretty close to actual now. I note this because even though the Power Wagon comes with 32" Duratracs stock, the tire size in the computer showed 28" when I hooked up the programmer to adjust it for my 35" Nitto RGs. It's now set at 34 to get the speedo exactly matching GPS speed.
 
Assuming 8 mpg, you would have a 240 mile range with 1 gallon to spare. I generally want to allow a 60 mile window for finding an acceptably sized and configured fuel station, so 175 miles should be safe. I agree though that 31 gallons is not enough. Toyota puts a 38 gallon tank in a Tundra with a 5 1/2 foot long bed. They aught to be able to squeeze a larger fuel tank in the 6.5 foot bed.
 
@JC thanks for the info, great to hear there might be a solution to correct the problem. I don‘t have a programmer, I tend to leave most things stock simply to avoid any potential issues with the warranty. I‘m a fan of leveraging technology to improve efficiency but I wouldn’t be able to sleep at night if something went wrong. The real issue I’m concerned over is the small size of the tank more so than the MPG. The tank is far too small for the consumption rate of the engine especially when you’re towing. I’m hoping when RAM does a complete redesign in the future they will fix the problem. Like Brucie mentioned above, there are competitors who have larger tanks hopefully we get the same.
 
Kimo7 said:
@JC thanks for the info, great to hear there might be a solution to correct the problem. I don‘t have a programmer, I tend to leave most things stock simply to avoid any potential issues with the warranty. I‘m a fan of leveraging technology to improve efficiency but I wouldn’t be able to sleep at night if something went wrong. The real issue I’m concerned over is the small size of the tank more so than the MPG. The tank is far too small for the consumption rate of the engine especially when you’re towing. I’m hoping when RAM does a complete redesign in the future they will fix the problem. Like Brucie mentioned above, there are competitors who have larger tanks hopefully we get the same.
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I would LOVE to have a 50 gallon gasoline tank. It costs the same amount to buy fuel in 50 gallon chunks over a trip as it does in 30 gallon chunks, but the safety, range and annoyance level would be hugely reduced with a 50 gallon option.

I loved my 2000 Ford Excursion 7.3L Diesel with the 44 gallon tank! That thing got right near 17-18 MPG empty with 44 gallons in the cell. Almost 800 miles to a tank, I loved it!
 
I suppose a larger tank would be 'nice', but I'm not interested in bladder busting distances...after a couple hundred miles, I'm ready for a break anyway.
I'm getting right at 16mpg on the interstate with the 6.4... 18mpg with a diesel is an insufficient increase in mileage to warrant the additional cost of fuel.
For my needs, a diesel is a money pit...
 
Gondul said:
I suppose a larger tank would be 'nice', but I'm not interested in bladder busting distances...after a couple hundred miles, I'm ready for a break anyway.
I'm getting right at 16mpg on the interstate with the 6.4... 18mpg with a diesel is an insufficient increase in mileage to warrant the additional cost of fuel.
For my needs, a diesel is a money pit...
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I'm sort of the same way after 2 hours, but I'd really like for my fuel stops to be four hours of driving apart, which the 6.4 just can just barely do on 31 gallons pulling a trailer on flat roads. You learn to live with it I guess. Just got the truck last fall and have taken two relatively short trips with a trailer. One two hours and the other five. Probably no trips this summer due to covid and barely driving the truck because most/all of my work is from home now. Going to be a long year ahead and I'm not too worried about how big my gas tank is now.
 
So back in Florida from Wisconsin... used regular Cruise Control the entire way back.
In hilly areas (Kentucky/Tennessee), the CC worked 'fine'... however, hit a long, flat patch and you can certainly feel the surging.

Best MPG was 16.5 using the CC... when the hills got steeper, MPG dropped to 14.7 despite the AVG MPG reading 15.9 as shown below.
As far as DTE and Range, it went from 10 miles to 'Low' and then I drove about another 5 miles to the gas station where I pumped 27.125 gallons.
This was my best MPG... ;)


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I’m back commuting to work in a little more traffic with increased stop and go. I filled up today, drove 320 miles on 25.12 gallons so I dropped to 12.7 mpg. The EVIC was displaying 13.5 average. :(
 
Just got back from a short trip towing the TT and did a hand calculation, running total on mileage to date beginning when I started paying attention to the fuel consumption rate. Tracking 1388 miles driven / 107.27 gallons fuel consumed = 12.9 mpg. Not too bad considering the weight of the trailer and stop and go driving.

I reset the EVIC before the tow and it was showing 8.9 mpg for the trip which isn’t bad considering the hills in our part of Virginia. The truck performed great, no issues with power or tranny, all temps stayed within range. Still very happy with the Hemi.
 
I have 1,600 miles on my truck and my Fuelly app average is 12.7. I sure hope it gets better. And I have not towed with it as of yet.
 
Stock everything with 4.10 is right at 14mpg with 89 octane and mixed hwy/city and stupidity on the road for me. Going on a 3 hr trip to the in-laws for new years so I expect 16 to peak through. Very excited to load it up with (hopefully) some fresh venison, sac-a-laits, and firewood. I don't need the firewood, but why not test it out and fill out the bed.
 
Mine from 13-13.5 MPG
 
Just over 10,000 miles on mine.
35” tires / 3.73
Always use 89 gas
speedo calibrated with AEV procal
I get 13.8 average around town mixed
16-17 highway road tripping
10-11mpg highway towing 6500lb depending on speed.
 
Rockcrawlerdude said:
Just over 10,000 miles on mine.
35” tires / 3.73
Always use 89 gas
speedo calibrated with AEV procal
I get 13.8 average around town mixed
16-17 highway road tripping
10-11mpg highway towing 6500lb depending on speed.
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That off the EVIC or of manual?
 
Gondul said:
Yeah, it may be my luck but they are, on average, at least 2mpg optimistic for me... and that's been on the last 4 cars (Honda, Dodge, RAM, and Subaru).
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Well then take my readings with a grain of salt.

mpg update: it is what it is ;)
 
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)
 
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