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2020 6.7 Cummins SO vs 2022-23 6.7 Cummins SO - Big MPG difference!

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aamescua

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Not sure if this has been discussed here in the threads, but I purchased a 2020 6.7L SO, and now have about 27k miles. I have a couple friends who have 2022 and 2023 Rams respectively, same 6.7L engine, same trim, same stock setup (Longhorn). While I'm here averaging 14-15 MGP highway at best, 9-11 MPG towing my 7k travel trailer (never a heavy foot), they're getting 17-19 highway, and about 15MPG towing basically the exact same size trailer as I have. Does anyone know if something changed after 2020? Maybe re-tuned? I can't find any answers.
FYI my fuel pump was just swapped out 2 weeks ago to the CP-3 from that big recall.
 
I'm leaving tomorrow morning for a Jeep trip that is taking me from San Antonio to lake Tahoe. I will let you know what my 2022 SO 2500 gets once the trip is over. My 2014 would get 10mpg religiously when i pulled this trailer/Jeep combo so 15mpg would be great by me.
 
My 2022 HO 3500 DRW gets 14.7-15 on the highway (hand calculated) the onboard software calculates it at 16.6. MPG.
 
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Computer readout on my 22 HO is between 20-21 here in the flat south
 
I owned an 18 2500 Laramie CTD and now own a 22 2500 Ltd Longhorn CTD. Same rear axle ratio. I pull the same trailers over the same roads at the same speeds. I have noticed a slight improvement towing, around 1mpg, but nothing dramatic.

MPG has so many factors. Weight, aerodynamics (boat vs travel trailer), speeds, terrain, etc, etc. If your friends are getting 15mpg, they must be driving slow, have a very aerodynamic trailer, etc. Or maybe a little embellishing too. Pretty common in MPG threads, that. But your unloaded highway mileage does sound low. My 18 would pull 21.5mpg hand calculated on long interstate stretches at 75-80mph. Haven't made a run like that in my 22, but I believe it would be about the same given the mpg's I've seen so far for it. Are your highway runs extended cruising runs or just short ones?

And never trust the computer readout. It is a best an indicator. It is rarely accurate.
 
jebruns said:
I owned an 18 2500 Laramie CTD and now own a 22 2500 Ltd Longhorn CTD. Same rear axle ratio. I pull the same trailers over the same roads at the same speeds. I have noticed a slight improvement towing, around 1mpg, but nothing dramatic.

MPG has so many factors. Weight, aerodynamics (boat vs travel trailer), speeds, terrain, etc, etc. If your friends are getting 15mpg, they must be driving slow, have a very aerodynamic trailer, etc. Or maybe a little embellishing too. Pretty common in MPG threads, that. But your unloaded highway mileage does sound low. My 18 would pull 21.5mpg hand calculated on long interstate stretches at 75-80mph. Haven't made a run like that in my 22, but I believe it would be about the same given the mpg's I've seen so far for it. Are your highway runs extended cruising runs or just short ones?

And never trust the computer readout. It is a best an indicator. It is rarely accurate.
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The axle ratios are not the same (unless you re-geared).

The ‘18 had 3.42’s and the ‘22 has 3.73’s.
 
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baker01 said:
My 2022 HO 3500 DRW gets 14.7-15 on the highway (hand calculated) the onboard software calculates it at 16.6. MPG.
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Yup. That is about what I get, Can't trust the Lie O Meter. Tries to blow sunshine up your keester to make you feel good. Most never hand calculate their fuel mileage.
 
CdnHO said:
Yup. That is about what I get, Can't trust the Lie O Meter. Tries to blow sunshine up your keester to make you feel good. Most never hand calculate their fuel mileage.
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@CdnHO haha yup, I would be one of them who never took the time to manually calculate it. I wondered if Dodge tweaked it to make it look better.
 
tchur1 said:
Nice rig! This has nothing to do with your question, but Rubicon trail? or headed elsewhere? I live about 300 yards from the trailhead.
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Yep, gonna run the Rubicon Trail and maybe Dusy Ershim. Gonna try to run Rocky Gap outdide of Vegas on the trip back to San Antonio
 
Well, San Antonio - Las Cruces was about 620 miles. I filled up twice and hand calculated averaged 8.4 mpg
 
tchur1 said:
right on, enjoy! Not sure if you've been out there before but its beautiful.
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Been in that area before but never ran the RT. Been trying to get out there for the last 3 summers. Finally gonna make it this time
 
aamescua said:
@CdnHO haha yup, I would be one of them who never took the time to manually calculate it. I wondered if Dodge tweaked it to make it look better.
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Oh yeah. I think most of their gauges are designed to meet "customer expectations", something they couldn't do with the old analog gauges. Now they can show anything they want you to see.
 
AH64ID said:
The axle ratios are not the same (unless you re-geared).

The ‘18 had 3.42’s and the ‘22 has 3.73’s.
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Thanks, good catch. And I should say my mpg comparisons from the 18 to the 22 are pretty much all towing. I rarely take my HD trucks on unloaded long interstate cruises, and it is decidedly not our "grocery getter".
 
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