We just got back from an 800 mile round trip pulling our 5th wheel. I found my truck likes to run at 2800 rpm on the Hwy. I would like to hear from all of you on how you pull on the Hwy. What gear are you in and what RPM are you at. If possible what Mpg are you getting pulling? Low mpg was 8.1 high MPG was 9.2

 

My truck seems to like RPM a bit lower, about 2400 or so.

I think it depends on how fast one is driving (aerodynamic drag increases exponentially) and the weight that's being towed or hauled. My slide in truck camper likely weighs much less than your 5er so the hp needed to keep it rolling is less than you require. Less hp = lower RPM. That's my hunch anyway.

 

What gear are you in and what speed when turning 2800rpm? What diff gearing does your truck have?

 

I'm similar unless I start hitting the hills. My mpg is about 1-2mpg less.

 

My 08 has 145,000 miles on it and 4.30s in it and runs around 2400 or so. I've pulled a 5th wheel 10,000 miles or so with 2000 mile trips to Florida 3 times since getting it back in 2015. Pretty solid at 7.5 to 8.5 mpg depending on head wind. I usually tow at 65 since these china bomb tires have been so poor lately (had one blow ) but I could easily do 70 and I'd probably make the motor a little happier at the higher rpm as I'd be more in the power band. One major tip I can provide is that the truck is totally different with the cruise on. The wimpy torque curves are out the window and the truck has much more power with it on. I don't use it on any steep grades as the ford downshift mapping is far too aggressive with a load on. I wonder if 5 star could modify the downshift patterns on the cruse?

 

Mine is a van, with 5spd automatic and 3.73 gears. Stock size tires of course.
I tow a enclosed car trailer that weighs 3500 empty and 7,000 loaded.
I always use Tow/Haul Mode when towing. I’m not sure what it does besides get higher rpm when upshifting, and same for downshifting (for engine braking).

I aim to keep speed at 65, but often creep up to 70.
I like cruise control on flat ground but I also agree with the previous person that it downshifts way too aggressively with cruise control on hills. I suspect it’s worse with my 3.73’s than everyone else’s lower gears. It’s annoying for it to downshift two gears just because it is losing a couple MPH. And then it seems to hang in that lower gear longer than necessary.

At 65mph it runs about 2250rpm and it seems to be good: except it hates hills.
And ive measured MPG quite a few times and it’s about 7.5-8mpg when towing.

 

My only gripe about an automatic.

 

Running in Over Drive at 75mph + with 4.88 gears.

 

That is the info I wanted to hear,

 

I am going to try it out next time we go.

 

OK, running at 75 MPH in OD at 2800 RPMs with 4.88 gears, still missing an important piece of the puzzle, what size tires? I'm guessing stock-ish 31.5"/32"?


The cruise control being on or off shouldn't make any difference in the engine's output or "torque curve", it's simply a method of controlling the speed to a set point. CC doesn't change the tune or shift strategy, using Tow/Haul mode will make the trans work differently.



The above mentioned trans performance items can be addressed with a good custom tune. My 4R100 (2V V-10 in an '05 EX) in stock tune would only hold OD under high load (like when towing up a grade) to about 45% throttle opening. With 5Star's 87 Performance tune loaded it will hold onto OD in the same situation up to about 55% throttle opening, which is great as the engine is making plenty enough torque to pull the load in OD. With the 89 Octane tune loaded (and matching gas) it will hold OD up to about 65% throttle opening on that same grade climb with the big TT on the hitch. The improvement in transmission shift strategy is the biggest gain you get with custom tunes, any additional engine output is just the gravy! I have the 87 and 98 Tow tunes but I have found them to be too aggressive for my towing style, they tend to downshift too soon and then hold the lower gear to higher RPM before shifting back into OD. The Performance tunes are a much better match for me and my towing style. Having the trans stay in OD more helps deliver better MPGs and the rig still handles the load very well at the lower RPMs in OD. It will drop down when needed but it then can regain a bit of speed quickly and drop back into OD again.


I tow an 11,000lb TT with our '05 2V V-10 4R100 with Banks headers and custom tunes in our '05 4X4 EXcursion with a 4" lift, 4.88s and 35" tires (effective ratio of 4.39). The combination crosses the scales at 19,440lbs lightly loaded, just the wife and I as well as two dogs and only a weekend's worth of supplies in the TT. I run between 63 and 70 MPH on the highway and typically see 8 to 9.5 MPG on our mostly highway trips, 65 MPH = 2230 RPMs and 70 MPH = 2400 RPMs. We have 20k+ miles with this TT and another 15K miles with the old 9,500lb TH. In totally stock form the 3.73 geared EX with 31.6" tires saw 6/7.5 MPG with the old TH in tow.
The addition of deeper gear made the biggest towing improvement and the tunes were second with the headers and muffler (3030XL) third.
For a couple of camping seasons I ran 32" tires with the 4.88s (4.80 effective ratio) and towed the old 9,500lb TH, that combo returned 9.0 MPG on highway trips spinning at 2430 RPMs at 65 MPH, no headers or tunes then. And almost never downshifted out of OD on the highway here in the East.

 

2430rpm at 65mph... what rpm at 70? And at 75?

ive been thinking at a gear change. And I like to “go big or go home”.
I have stock tires, and I believe my 5r110 is the sameOD ratio as your 4spd Auto. (Right?)

 

Yes, the OD ratio is the same in both transmissions.
I didn't list the RPMs because I didn't tow above 65 MPH back then because the TH had the typical 65 MPH max speed rate crappy ST tires, if you want to tow faster make absolutely certain that your trailer tires are rated for the speed. My new TT tires are rated for the speeds I tow now, I try to limit myself to 70 MPH.
With the 4.88s and the 32" tires it turned 2600 RPMs at 70 MPH and 2760 RPMs or so at 75 MPH. And it was in beast mode all the time!

 

my questions about rpm weren’t actually related to towing; sorry.
I wouldn’t care if it’s running 4200rpm while towing, because my longest tow (at speed) would be 90 minutes.

I wanted the info because I don’t/wouldn’t want the rpm too high for unloaded highway use. And yes, 2600 is too high IMO for highway driving at my needs.

 

Excellent technical discussion!

I have to confess I have been a long time lerker on the v10 form. I got my v10 1.5 years ago and have been getting it ready to replace my other truck for tow duty.

Tow Truck is a 2010 F-350 4x4 CC LB, Rancho 9000 shocks, ride rite air bags, Hellwig 30mm sway bar, Cooper ST Maxx LT295/70R18, Detroit True track in front, Detroit Locker in rear, 4.88 Nitro Gears, 5 Star 87 tow tune, RDS Fuel tank & tool box,

Well last weekend was the shake down run for the v10 pulling the 5th wheel which is a little less than 11k lbs full loaded.

The truck pulled better than I expected. It was a lot of fun to drive, yes I know 75mph-80mph (5th wheel has LT tires on it) is too fast to be pulling at but I wanted to see what it would do and it did it well.

Thanks to you all and WE3ZS for a the info/details, it helped me build a darn good gas powered tow rig!