3.92 Mileage Disappointment

[2020_Longhorn]

Enjoying my new 2020 Longhorn that came with 5.7 Hemi eTorque with 3.92 gears. I live on the Texas coast but I drove my first ram as a rental and it was a 2019 Laramie with 5.7 Hemi that I drove while in Colorado. During that trip of about 300 miles or so I averaged 21 mpg. Most of it was highway in and out of the mountains and some city driving as well. I was thoroughly impressed with the mileage considering I was averaging about 70 on the highway. Obviously the Laramie had 3.21 gears. I was hoping to do the same with my truck. Possibly the different altitude and tuning have something to do with it, I'm not sure. I took my first highway trip this past weekend starting with about 700 miles on my odometer. I did some tests while driving on the highway on nice flat highway without much wind blowing and no downshifting. I know these are not very accurate numbers with a small sample set, but it does not give me much hope. I drove about 20 to 25 miles at several speeds using the cruise control and noted mileage and rpm. After each test I just reset the average mpg and kept rolling without pulling over.

MPH RPM MPG
75 2100 17.0
70 1950 17.4
65 1800 17.8
60 1650 19.4
55 1500 22.4

I was curious to see if someone with a 5.7 and 3.21 gears could test a bit and post their results at the same speeds. I am really curious to see what your rpm is at 75, I am guessing close to 1600 rpm. Getting to 1500 seems to be the sweet spot, but like Sammy said, I can't drive 55 either.

I have not checked to see how much it would be to swap to 3.21 gears yet. I currently do not tow anything so the 3.92 is not necessary for me. I do, however, enjoy the performance I plan on keeping the truck for some time so long term mileage may be of interest to me. Around town I only get about 13 mpg rarely revving over 2500 rpm. I realize my engine is not really broke in yet and will probably get better mileage over time, but I realistically don't expect it to get much better. Please share your thoughts and results of 3.21 and 3.92 gears.

Brian

 

[Zeeya]

Build date 5/19, purchased 6-19. Currently at 24,000 miles and I have went through the same scenario as you have. 2100@75. 806 mile trip every two weeks out to W Texas. Your numbers are about right. Once in a blue moon I'll get a good tail wind and will get 18 to 19 @75. Just took a trip up to Mississippi for a quick hunt. Roads traveled were 55 - 65 mph speed limit. I stuck to the limit just to see and for that 350 miles I showed 18.8 average.

 

[PorBoy]

I have not done extensive testing but my Laramie with 3.92 I’m averaging 13.9 mixed driving. Plus I have the smallest tank known to man, a fact that I am not proud of lol.

 

[Zeronet]

Just took a 500 mile highway trip to Orlando and back in my 19 Longhorn 5.7/3.92 with 8000 miles on it.

On the way up with ~500lbs cargo and 2 passengers averaged 19.5 doing 68-73mph with adaptive cruise on. On the way back with only passengers averaged 20.0 at the same speeds. Noticed on the way back that it was able to hold MDS on, even at 73mph on flat ground. I have seen as high as 24 average on a couple of pure highway trips but at 65mph without cruise control trying to be as efficient as possible.

Around town I see 15-16.

All based on the lie-o-meter on the dash.

 

[RJS]

Give it a few thousand miles and then worry about it if the mileage doesn't improve.

 

[spaightlabs]

1) If you bought a full-sized truck for good fuel mileage you were destined for disappointment.
2)your mileage will improve some as the break breaks in.
3)the only accurate way to calculate mileage is by hand.
4) see #1.

have fun, life is short and gas is (relatively) cheap.

 

[GRAYWOLF]

Last several tanks in my 19 LoneStar non-eTorque with 3.21.

They higher ranks are road trips...I mostly just drive back and forth to work through town and grocery store trips.

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[Firebird]

Don’t forget, winter blend fuel will affect your mpg

 

[AtlasRam1500]

I had a 2019 Laramie 4x4 5.7 3.21 i was avg city 15.8-17.5
Hwy was 17.5-21 mpg
if i stay long haul hwy i would avg about 21 Speed about 73mph

Now i have a 2019 Limited 4x4 3.92 now i, getting 13.5-14 city and 16.5-18 hwy im so disappointed. if it was easy to do i would swap my gears in a heartbeat.

 

[Rob5589]

Based on the complaints here, you're doing better than most. A full sized truck at 75 mph isn't going to knock down some spectacular mpg.
The best I have seen with 3.21's is 21.8, pure freeway. Around town it drops into the high 15 to mid 16 range.
Find the post I made on the mileage thread that describes how mpg numbers are achieved. I can tell you, it does not include driving 75 mph.

 

[airgas1998]

here i'll make you feel better..i'm getting 11.4mpg all city with 3.21's......i just love these threads.... as if you buy a truck and then you become disappointed in the mpg it puts out...

 

[Reverse]

We have a 2014 and a 2020 Ram, identical drivetrains (5.7/3.92) 2020 has etorque. 2014 has 20" wheels, 2020 22". Both 4x4 crew cabs.

On average, on the same commute, using same gas etc. the 2014 gets 2mpg more than the 2020 (19 vs 17 for the 2020).

 

[Jwsmith]

Just did a 60 mile test Thursday with a Max speed of 58 and 3 villages that dropped to 30 mph for a few miles each, 36°, 2WD, and had an indicated 24 MPG. I'm around 1250 RPM at 55. Have a dash indicated 18.0 average right now with 10,700 miles. I'm 50/50 on highway/city with 80% of the city 25 MPH short trips of less than a mile. Tires are at 40 PSI. There are a lot of variables, including driving style. On a trip in October (3,700 miles) with a friend of mine I averaged 2 MPG better than he did.

 

[snj1013]

Don’t forget, winter blend fuel will affect your mpg

I agree.

 

[CrazyWorld]

I love the mileage of my new truck. 5.7 and the 3.92...4x4...tow package. Highway....going 65ish....20 to 21mpg. Around town....averaging about 17mpg. I think that is great. If I drove 75 highway and floored it at every stop light....I would expect mileage to go down. I am retired.....don't need to go fast....thus....better mileage.

 

[2020_Longhorn]

Thank you all for the input. I did not buy this truck to achieve Prius like mpg numbers, but I do expect to get a little closer to the sticker numbers as I did in Colorado with the rental. I will give it some time and decide what to do at a later date. In the mean time I am really enjoying all the great features of the truck. How can I tell when MDS is activated, is it when the ECO light is on? If it has been coming on it appears to be seamless as I have not noticed.

Brian

 

[Zeronet]

How can I tell when MDS is activated, is it when the ECO light is on? If it has been coming on it appears to be seamless as I have not noticed.

Yes, the ECO light will indicate when MDS (cylinder deactivation) is on. If you’re not seeing the ECO light there’s a setting for enabling the light in the infotainment settings.

 

[ramhead]

1) If you bought a full-sized truck for good fuel mileage you were destined for disappointment.
2)your mileage will improve some as the break breaks in.
3)the only accurate way to calculate mileage is by hand.
4) see #1.

have fun, life is short and gas is (relatively) cheap.

Yep...and as has been said before - if you bought a 1/4 ton or larger pickup truck with a V8 and are worried about the gas mileage...you bought the wrong kind of vehicle.

 

[Konrad]

Enjoying my new 2020 Longhorn that came with 5.7 Hemi eTorque with 3.92 gears. I live on the Texas coast but I drove my first ram as a rental and it was a 2019 Laramie with 5.7 Hemi that I drove while in Colorado. During that trip of about 300 miles or so I averaged 21 mpg. Most of it was highway in and out of the mountains and some city driving as well. I was thoroughly impressed with the mileage considering I was averaging about 70 on the highway. Obviously the Laramie had 3.21 gears. I was hoping to do the same with my truck. Possibly the different altitude and tuning have something to do with it, I'm not sure. I took my first highway trip this past weekend starting with about 700 miles on my odometer. I did some tests while driving on the highway on nice flat highway without much wind blowing and no downshifting. I know these are not very accurate numbers with a small sample set, but it does not give me much hope. I drove about 20 to 25 miles at several speeds using the cruise control and noted mileage and rpm. After each test I just reset the average mpg and kept rolling without pulling over.

MPH RPM MPG
75 2100 17.0
70 1950 17.4
65 1800 17.8
60 1650 19.4
55 1500 22.4

I was curious to see if someone with a 5.7 and 3.21 gears could test a bit and post their results at the same speeds. I am really curious to see what your rpm is at 75, I am guessing close to 1600 rpm. Getting to 1500 seems to be the sweet spot, but like Sammy said, I can't drive 55 either.

I have not checked to see how much it would be to swap to 3.21 gears yet. I currently do not tow anything so the 3.92 is not necessary for me. I do, however, enjoy the performance I plan on keeping the truck for some time so long term mileage may be of interest to me. Around town I only get about 13 mpg rarely revving over 2500 rpm. I realize my engine is not really broke in yet and will probably get better mileage over time, but I realistically don't expect it to get much better. Please share your thoughts and results of 3.21 and 3.92 gears.

Brian

Subtract 250rpm and add 2.3 mpg to each of your results and you'll have almost exactly what I got (+/- 0.1 mpg) today on my BigHorn (5.7 eTorque Quad Cab 4x4, 3.21) as I went there and back on a 25mi fairly flat, empty stretch of expressway with virtually no wind. Empty truck+full tank+me (220#). 34F outside. 87 octane gas. These are averages from both runs, Lie-o-meter readings, not real consumption of course.




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[GRAYWOLF]

Don’t forget, winter blend fuel will affect your mpg

Not sure what they do in other parts of the country, but here in TX they stop adding ethanol (or reduce) for winter. That, supposedly, improves mileage...I have not noticed a difference.

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