Towed 550 miles over two days. 5er is completely loaded to max gvwr, even had fresh water on board. I'm going to say it was about 12k#. I ran through hills, up mountain grades, into stiff winds and through lots of rain.It ran in 5th gear most of the time at 2100 rpm @ 65 mph. Into head or side winds it would drop into 4th to maintain speed. Grades would require 3rd gear at about 3k rpm, and once I hit the mountain grades I saw 2nd gear at 5k rpm a couple times. Temps were all in check, including transmission. There was only a couple times I couldn't have accelerated if I wanted to, and that was when I had to drop into 2nd. Interesting that it can do 60 mph at 5k rpm in 2nd.Mpg was 8.1 over the two days, as low as 6 into the wind and as high as 12 when it was behind us.Very happy with how it performed.

Wow,You traded in a Cummins for the gas engine? Glad to hear it was going up the hills at 60. My gas engine motorhome will out run my buddy's 28,000 DP!Fred.

Sounds like the truck performed very well. The Hemi's are a great engine. :) Congrats!

I was quite surprised at how it would lug up the slight grades in 5th where I was expecting a downshift. I know in all the press events they were bragging about the fact that the 6.4 makes more tq down low than the competition, and the 5.7. I can tell you it feels like it to me.It's certainly no Cummins, but it did very well today.My 5.9 Cummins would get 10-12, usually 11 mpg pulling this same RV.

ib516 wrote:I was quite surprised at how it would lug up the slight grades in 5th where I was expecting a downshift. I know in all the press events they were bragging about the fact that the 6.4 makes more tq down low than the competition, and the 5.7. I can tell you it feels like it to me.It's certainly no Cummins, but it did very well today.My 5.9 Cummins would get 10-12, usually 11 mpg pulling this same RV.It will be interesting to see what this, the Eco Diesel 1500, along with the Cummins does for Ram sales.They seem to have a one, two, three punch.

Good for you. Sounds like the new Ram is working out nicely for you. It's always a happy ending when expectations/hopes are equal with reality.

6.4L Hemi tow report - weights added | Good Sam Community

nirion
Explorer
Aug 10, 2014
I have a comparable sized 5th wheel. I am looking at going to a 4th gen Ram, and I have read both of your larger threads on the new truck. I am still deciding between 6.4 and Cummins. Drove both a couple miles yesterday and was impressed with the low end in the 6.4.

Obviously it is handling the trailer well, but any regrets so far? Missing the diesel when you were climbing the grades? How steep were the grades when you had to drop to 2nd?

Thanks
ib516
Explorer II
Aug 10, 2014
Snapped a pic of gauges at ~62 mph in second gear, visible at the bottom of the display. I have the ERS set to 5th. Its at about 4800-4900 rpm.

You can see the avg of 25.5L/100km = 9.22 mpg at that point about mid way through the foothills. Just above the green cruise control icon.
ib516
Explorer II
Aug 10, 2014
Dup deleted
ib516
Explorer II
Aug 10, 2014
Shorter trip today, only 300 miles. Averaged 9.1 mpg. No wind (which is likely the biggest factor to the improved mpg) but some decent grades as we neared the mountain rv park we are in.

I bought a tank of 89 octane as well, but not sure if that contributed to slight mpg improvement.
ib516
Explorer II
Aug 10, 2014
texasclarks wrote:
ib516 wrote:
Oh btw I tested it out, it will do about 73 mph (115 km/h) in second gear at redline. It shifts (when in tow/haul mode) at 5600 rpm if held to the floor.

I don't know if I could stomach 73mph in second gear. I know that gas engines CAN wind up all the way past 5K rpm, but I wouldn't be comfortable doing that. I probably wouldn't be a good NASCAR driver ;)

Lol! :)

It doesn't stay there long, and pulls hard above 4000 rpm or so.

Remember this engine is based on the "392" hemi they use in the SRT cars, just detuned a bit and designed for more tq at lower rpm.
texasclarks
Explorer
Aug 09, 2014
ib516 wrote:
Oh btw I tested it out, it will do about 73 mph (115 km/h) in second gear at redline. It shifts (when in tow/haul mode) at 5600 rpm if held to the floor.

I don't know if I could stomach 73mph in second gear. I know that gas engines CAN wind up all the way past 5K rpm, but I wouldn't be comfortable doing that. I probably wouldn't be a good NASCAR driver ;)
Hannibal
Explorer
Aug 09, 2014
Don't be shy ib, go ahead and let it roar! :B
ib516
Explorer II
Aug 09, 2014
Oh btw I tested it out, it will do about 73 mph (115 km/h) in second gear at redline. It shifts (when in tow/haul mode) at 5600 rpm if held to the floor.
ib516
Explorer II
Aug 09, 2014
Stopped at a self weigh on the highway between campgrounds.

Truck:
Front 4478#
Rear 5302#
Total: 9780#

Trailer axles: 10780#

Hitch wt: about 2100# by math
Truck empty 7000
Passengers 450
5er hitch 150
Junk 100

Gcw: 20560

5er total about 12700#

I didn't unhitch just drove over scale and weighed each axle.
Buck50HD
Explorer
Aug 08, 2014
ib516 wrote:
Buck50HD wrote:
Actually, the 6.4 Hemi is the only one where I had only the HP and TQ peak and had to estimate the curves from the 4 points.

The 6.4 Hemi needs a lower 1st and 2nd gear, even with the 4.10 rear. The 3.73 cripples it even more. At highway speeds, it's not possible to get full power.

Have to disagree with you about the power at highway speeds. I mean you're really going out on a thin limb there based on your guess about the power curves.

No matter, pickuptrucks.com is about to solve the mystery in a week or so, when they release the latest HD shootout.

I was referring to normal highway towing speed of 60-65mph. If you run interstate speeds, it's going to get to peak power in 2nd gear. It looks like 71MPH would be right at 5600RPM. The other opportunity is around 40MPH in 1st.

The numbers are definitely approximate. I will spend some more time on it and see if there are any major errors more than 5HP. Initially, I see that the 6.4 should probably be closer to 365HP in 2nd gear, the same as the 3.73 6.2.

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