Duramax towing MPG

[Renze]

In Europe things are different than here. But in all honesty many people tow 7,500# or more behind 1/2 tons that weigh 5,500# like me. I also tow 15,600# every weekend behind my 7,600# 1 ton SRW and many tow more than that.

Biggest difference between pickup towing, and family car towing, is the tongue weight you can put on a pickup: In Holland we tend to place the tandem 2 inches behind the middle of the bed, to not exceed drawbar load. Most pickup bumper pulls i've seen, have the axles at 2/3 of the bed.
A 3.5 ton surge brake head with coupler, is usually rated for 150kg vertical load.

 

[Renze]

What I don't understand is how I can get 10.2 to 10.5 mpg (running the speed limit) with a 35,000 pound coach being powered by a Cat C9 http://ohe.cat.com/cda/files/448361/7/LEDT7015 -C9 Engine Brochure 8.9.07.pdf engine.

The brochure itself, reveals its secret:
Gearing Considerations
The C9 engine offers a wide operating range and
high torque rise for compatibility with a wide range of
transmissions. For best performance, trucks should be
geared to achieve the appropriate balance between
startability and desired road speed, and drivers should
follow 敵ear Fast, Run Slow techniques.
For the best balance of performance and economy,
spec axle ratios and tire sizes according to the following:
60,000 lb GCW or less
1150 lb-ft: 1650 rpm @ 65 mph (105 km/h)
1250 lb-ft and above: 1600 rpm @ 65 mph (105 km/h)
To optimize your truckç—´ performance characteristics,
the minimum startability requirements are 10%
for pickup and delivery, 14% for line haul, 20% for
on/off-highway and 25% for off-highway.

 

[capt_met]

i had a chevy D/A 4x4 dually 3500. towing around 14 i stayed around 11-13 depending on the hills/speed i was cruising. my present 4500 4x4 gets 12-14 towing the same weight. when towing 9 tons with a bumper pull trailer and excavator it drops to 10-11 on the interstate. rarely do i run much over 70 when towing heavier loads.

 

[George2615]

Prior to the added pollution reducing DPF on the Dmax (early 2007) my Dmax, an 05, got 20 MPG empty and 15 MPG while towing 7500#.

I regrettably traded in the 05 for an 07 (with DPF) and the MPG went to 15.5 empty and 11-12 towing the same load.

The new Dmax coming out has an additional urea system which will probably not add any MPG. I don't do a lot of towing so I went back to a gas truck with a 5.3 and get 17.5 empty and 12.5 towing the same load. It may get better when the truck breaks in.

As for towing 14K, a diesel truck will get you better MPG than your getting with your 8.1L. Don't know if you'd double the MPG but you should come close.

 

[Diamondpilot]

Big thing with towing is where, what, and how you are towing. Lets say you are towing your trailer up and down hills in a mountian area the diesel is going to win every day. Towing around town, short hops, lower speeds (below 50 mph), you may not see such a big differance.

Case in point. I stated earlier my neighbor has a 2007 Classic, non dpf 3500 SRW 4x4 Dmax 3.73 gears. It gets about 20 mpg on the highway at 70. Any faster and it drops considerably. Around town it averages 12 mpg for him. He is a commercial mower and tows a tandem 16' landscape trailer 4 days a week pulling 2 ZTR's at 1,200# each plus the trailer at 1,500# for a total of 3,900#. Now he just got back from a trip that was 9,000 miles over 4 weeks and averaged just over 11 mpg pulling 12,000# 5th Wheel.

His previous truck was a 2005 F-150 5.4L 4x4 with 3.73 gears. He pulled the same trailer for his landscape business. He got 13 mpg average, actually better than with the diesel. It would only do 16 on the highway though with no load compared to the 20 mpg his Dmax gets. He pulled a 7,000# travel trailer back then and got 10 mpg versus the 11 mpg the diesel gets. Of course the diesel is pulling nearly twice the load and does it much better but there is no significant increase in mpg while towing.

As for maintenance I do it all for him except for the warranty work. I do preventive stuff on all his equipment including dump trucks, tractors, dozer, mowers, trucks, suv's, go carts for the kids, ect. Sunday I did a 60,000 mile service. I put on a new fuel filter @$40, new air filter @$65, a oil change 10qts syn 5W40 and filter was $75, and rotated the tires which are nearly worn out (2nd set). As you can see its expensive. We do 7,500 mile oil changed and all other filters are at 20,000 miles.

Chris

 

[Dmace]

If your not dead-set on getting a brand new truck then maybe look at a used diesel truck. Like the others have said, if you want better MPG's then look for a pre-DPF truck like the pre-05 6.6l Duramax, pre-07.5 5.9l Cummins, or pre-04 7.3l Powerstroke. It will be harder to find exactly the truck you want but will be MUCH cheaper up-front and will pay for itself MUCH earlier than a new truck. That may turn the significant other towards a purchase.

 

[Cat_Driver]

I had an 04 3500 SRW Duramax and a Duramax 05 Dually and could never ever come off between 10-12mpg EMPTY. I duped them both.

I know it's advertising but I was impressed by ......
2011 Ford Super Duty Trucks | Built Stronger. Tougher. Better. | FordVehicles.com

 

[CCOUGHRAN1]

I had an 04 3500 SRW Duramax and a Duramax 05 Dually and could never ever come off between 10-12mpg EMPTY. I duped them both.

I had similar experiences with the older D/A trucks. I loved the ride, interior, and dual climate a/c, but I could not get the mileage out of them, especially not anything like the guys are claiming in some of these posts. Maybe I had 3 lemons

 

[Dmace]

I know it's advertising but I was impressed by ......
2011 Ford Super Duty Trucks | Built Stronger. Tougher. Better. | FordVehicles.com

Don't be too impressed. If you listen closely the "chief engineer" says they are similarly equipped with the "LOWEST NUMERICAL AXLE RATIO". That is the kicker right there. For those that may or may not know, the lower the numerical number, the taller the gear.
Lowest numerical axle ratio offered:
Ford - 3.31
Dodge - 3.42
Chevy - 3.73

So they were not "similarly equipped". The Ford had taller gearing which means the rpms were lower at the rated speed which lead to the better fuel mileage. If they all had the same rear axle ratio (they all offer 3.73), I bet the outcome would be different and I bet the RAM Cummins would be on top. It's Ford doing what they do best, playing the numbers game instead of actually showing a true FAIR competition.
Motor Trend did a true FAIR competition and the RAM heavy duty truck came out as Truck of the Year for a reason.

 

[Ryan03]

I had an 04 3500 SRW Duramax and a Duramax 05 Dually and could never ever come off between 10-12mpg EMPTY. I duped them both.

I know it's advertising but I was impressed by ......
2011 Ford Super Duty Trucks | Built Stronger. Tougher. Better. | FordVehicles.com

A freind has an 04 CC SB 4x4 DMAX [LLY version]. It has a hard time breaking 15MPG on the highway empty. My 03 LB7 Reg cab 8 ft box 4x4 gets 19 to 22 empty on the highway, and the worst towing mileage ever was 13 mpg towing a 15k mini excavator and trailer. I normaly tow a 7-9k 28 ft enclosed, and get 14 to 17 depending on wind and how much of a hurry I am in