Very Poor fuel economy 2019 6.4

[ptlawn]

I have a 2019 ram 2500 crew 4x4 6.4. Has 2700 miles. I hauled a dodge challenger in an enclosed trailer. Car and trailer weighed in 7800 lbs. Mostly flat ground very little hills western Kentucky area. Hand calculated 4.6 mpg. Dealer said cou;ld be normal.God I hope not

 

[oaklandopen]

That does sound horrible, but it would help if you also gave information on speed, type of driving like stop and go or highway ratio, any extra idle time, final drive ratio, and if that number was hand calculated. I also think an enclosed car carrier rivals top fuel drag car parachutes as far as aerodynamics

Wish I could give you better numbers on my end but I haven't towed heavy yet and my TT is probably the same weight as that.

 

[Deleted member 80]

Excessive idling, or towing at 80 mph aside, when I had my 2015 6.4 with 4.10 gears I pulled a 41' gooseneck toy hauler that put me over 23K lbs combined, and the worst I saw was 6.5. It usually hovered in the 7.5-8.5 range. I generally tow at 65 max. That is some really poor mpg you are seeing.

 

[slimchance]

when i pulled my 10,500# 5er thru the mts of Pa i hc 9.5 mpg ... see my fuelly for non towing mpg

 

[Motoman501]

On Sunday I towed my 32ft 8000lb travel trailer home from a camping trip. At 5000ft with rolling hills and into a decent headwind, I averaged around 6.5mpg with the speedo at 60mph.

 

[oaklandopen]

With that elevation you're also working with like 50 less hp too. Did it seem like it was dogging it the whole time?

 

[Motoman501]

It actually towed well. There were a few hills that although relatively short, were pretty steep. The truck shifted down to fourth gear and ran as high as about 3900 rpms but held speed the whole way up.

My previous truck was a 2015 Cummins which made this same trip without any wind at around 9.5 mpg. Wind and hills do seem to affect mileage more on the Hemi but had it been calm, I think the mileage would have been a lot closer.

 

[ptlawn]

That does sound horrible, but it would help if you also gave information on speed, type of driving like stop and go or highway ratio, any extra idle time, final drive ratio, and if that number was hand calculated. I also think an enclosed car carrier rivals top fuel drag car parachutes as far as aerodynamics

Wish I could give you better numbers on my end but I haven't towed heavy yet and my TT is probably the same weight as that.

99% highway driving.no idle time, hand caluated

 

[slimchance]

i had a 2005 Dodge 2500 HD, quad cab, w/8' bed, 5.7 Hemi, w/4.11 rear ... great trk, traded with 130,000 miles and NEVER had a problem with it, BUT it always got 11 - 12 mpg hand calculated, did not make a difference loaded or unloaded .... now that is BAD mileage ..... my 2019 Ram 2500, w/8' bed, 3.73 rear and 6.4 Hemi w/MDS gets on average 14.8 mpg hc

 

[Blazin383]

When I tow my 10,000 lb bumper tow toy hauler with my 15 2500, 6.4 Hemi, 4:10, I get about 7-8 mpg per the computer. I recently bought a 2,900 lb, 8.5’x20’ Vee Nose, Flat Top cargo trailer. Had to drive a couple hundred miles to get it. Towing it home empty I got... 7-8 mph! Blew me away that the empty 20’ trailer would drag the mileage down as bad as the 10,000 lb toy hauler. I still don’t understand it, but wrote it off to use of the Tow/Haul button. One of the biggest reasons I’m trading the Hemi for the new HO Cummins.

 

[Motoman501]

Last month I towed a 10ft utility trailer with a Kawasaki Teryx4 and bed full of hunting supplies from Reno to Arizona. It was windy most of the trip but I only averaged about 8-9 mpg at 70-75 mph. It seems with even a relatively light load the mileage drops a lot. I could have driven slower but it's a really boring drive....

 

[Wileykid]

When I tow my 10,000 lb bumper tow toy hauler with my 15 2500, 6.4 Hemi, 4:10, I get about 7-8 mpg per the computer. I recently bought a 2,900 lb, 8.5’x20’ Vee Nose, Flat Top cargo trailer. Had to drive a couple hundred miles to get it. Towing it home empty I got... 7-8 mph! Blew me away that the empty 20’ trailer would drag the mileage down as bad as the 10,000 lb toy hauler. I still don’t understand it, but wrote it off to use of the Tow/Haul button. One of the biggest reasons I’m trading the Hemi for the new HO Cummins.

Pretty much it is all about aerodynamics, and I have spoken to some people who have said the "V" nose doesn't help a whole lot. Weight does effect it, but it is all the drag from the trailer that screws with the mileage. Almost as important is speed. With my toy hauler, from 65 mph to 75 mph, I lose 5-6 mpg. Drag increases at the square of the speed increase. A TT is worse than a 5th wheel.

 

[Kimo7]

I just bought the 2500 with the 6.4 because it was MUCH cheaper than the Cummins. I had a lot of engine problems with my 2017 Limited 2500. The crank seal was leaking and had to be replaced twice before 30k miles. FCA customer service was excellent helping me get it resolved but I no longer had confidence in reliability so I got rid of it. I opted for the 6.4 gas engine in the 2019. The Cummins was a beast and towed our 6500 lb travel trailer effortlessly but I just never bonded with that truck.
We recently traded our travel trailer so I had a chance to see how the new truck performed towing. I towed the old 6500 lb trailer about 150 miles to trade it in, most of the trip was on I-95 at whatever the posted speed limit was. I got a little over 9 mpg going down. The new trailer is 9100 lbs dry and we repeated the exact same route on the journey home. A lot of the time the truck did operate at higher RPMs than I felt comfortable with but the systems were within temperature and pressure ranges. I had to remind myself I was towing nearly 3 tons so it makes sense it would rev a little higher, even on flat level ground. I got a solid 8.8 mpg going home. The figures were from the truck EVIC system. By contrast the Cummins diesel only got in the 9 mpg range too while towing and it would also burn a lot of DEF fluid dependent on engine load.
The new truck did great handling and was very stable with 1130 lb tongue weight on the bumper. The 6.4 Hemi has the power to move the trailer and is super responsive. The diesel was slow to spool up, no quick moves with that one but it definitely was unstoppable once it did get going. The 6.4 HD seemed like the best all around choice this time for what I wanted, daily driver, HD capable and can tow over 10,000 lbs, 10-12 times a year. Most trips are less than 400 miles.
As a daily driver and I’m getting around 12 mpg in the stop and go driving traffic of Northern VA. The 6.4 is quick and powerful, I’m very happy with it so far. I’m hopeful it hits the sweet spot balance of reliable daily driver that is HD capable.