Duramax towing MPG

[brain55]

Does anyone have some real world mileage numbers for a 2010-2011 K3500HD with the Duramax and Allison 6-speed towing 14K+. I'm curious, I think I can just about justify a new truck on fuel savings alone, switching from my 2001 K3500 with the 8.1L and 5-speed Allison. I'm towing a 14K+ lb GN trailer almost daily, and getting in the 5 MPG neighborhood. I'm spending roughly $1000 a month on gas. If I can cut this in half or close to it, the cost of a new truck might be worth it.

Brian

 

[CCOUGHRAN1]

I seriously doubt you will cut the number in half. Just this weekend we traveled 700 miles with friends. I was in my 5.9 Dodge 3500, my buddy was in his 2010 GMC D/A K3500. I was pulling a loaded 24' stock trailer, he was pulling a 20' equipment trailer with a Polaris Ranger on it. He was averaging 10 mpg, I averaged a hair over 14. We were running 65-70 all highway, about 50/50 flats and hills.

In our area,
87 gas is 2.46 gallon
diesel is 2.90 gallon

Figuring $1000.00 @ 2.46 I assume you are burning 400 gallons, and running ~ 2,000 miles per month.

Take the same 2000 miles per month with a D/A loaded to 14k, and I have my money on 8-9 mpg, lets say 8.5... Running 2k miles at 8.5 mpg, you will use 235 gallons @ 2.90 = 682.34 per month in fuel. Add up the additional cost of diesel oil changes, fuel filters, and the margin shrinks even more.

My best guess is that you will save about 300.00 month in fuel, on the high side.

 

[AKfish]

Are you referring to the latest GM truck with the urea injection system?

AKfish

 

[nmu98]

Aerodynamics will play into your question. Pulling a 14K fifth wheel or 14K of iron?

I towed around 10K of tractor and implements on an equpment trailer and would average 10 to 11 on the expressway if I was 65 or under. The regenerations that new vehicles go through to clean the dpf hurt mileage.

The 8.1 sucks fuel no doubt, but I doubt your plan would be a dollar making venture. The increased maintenance, higher insurance and higher fuel would take its toll.

 

[CharlieS]

My son drives an 08 Chev with the duramax/6 sp. allison. Pulling a 20 ft bumper pull enclosed snowmobile trailer (10K + lbs) in the colorado and wyoming mountains at reasonable speeds for the roads encountered, consistantly does 14+ mpg.

 

[bdeboer]

'08 2500 Chevy with Duramax Allison Crew Cab Shortbed. Just averaged around 12 mpg pulling a 30' bumper pull RV on a 1200 mile round trip from Central Ohio to Marylands eastern shore.

Truck consistantly gets high teens without the trailer on freeway trips, occasionally 20.

Seems to be around 15-17 rural driving.

 

[brain55]

Aerodynamics will play into your question. Pulling a 14K fifth wheel or 14K of iron?

I'm pulling my mobile shop. So it is 14K+ lbs of weight, not just rated for 14K.

Brian

 

[Renze]

Towing a 2 horse Vee nose trailer on short trips, my S70 TDI uses 9 liter per 100km. Thats a bit over 11km per liter or 6.9 mile per liter, or 26 miles to the gallon... On long highway trips towing 5k pounds (tractor on a 20ft utility trailer) i get similar numbers... With 140hp and 300+ Nm its still plenty fast for hauling horses.
Downsizing (reducing dead weight) would get you more economy than just trading it for a Diesel.

 

[Diamondpilot]

Does anyone have some real world mileage numbers for a 2010-2011 K3500HD with the Duramax and Allison 6-speed towing 14K+. I'm curious, I think I can just about justify a new truck on fuel savings alone, switching from my 2001 K3500 with the 8.1L and 5-speed Allison. I'm towing a 14K+ lb GN trailer almost daily, and getting in the 5 MPG neighborhood. I'm spending roughly $1000 a month on gas. If I can cut this in half or close to it, the cost of a new truck might be worth it.

Brian

I had a 05 Dmax 3500 4x4 SRW and with 15,600# behind it I would get right at 13 mpg when not in the shop. It had 3.73 gears. I was pulling a boat that was very aerodynamic. My neighbor has the same truck but in a 07 and he tows a 12K 5th wheel and just got back from a 9,000 mile trip. He averaged 11.3 mpg. His low as 8mpg and his high was 12 something. Again aerodynamics play a big role.

All 3 Ford diesels I have owned get a little better towing but did not do as good unloaded as compared to the Dmax. Go figure.



Chris

 

[aczlan]

Towing a 2 horse Vee nose trailer on short trips, my S70 TDI uses 9 liter per 100km. Thats a bit over 11km per liter or 6.9 mile per liter, or 26 miles to the gallon... On long highway trips towing 5k pounds (tractor on a 20ft utility trailer) i get similar numbers... With 140hp and 300+ Nm its still plenty fast for hauling horses.
Downsizing (reducing dead weight) would get you more economy than just trading it for a Diesel.

You tow 5000# behind a S70? Thats a lot of weight for a 4000# car.

Aaron Z

 

[timswi]

I was planning on buying a DMAX for my next truck..If the EPA version is this bad, I'll stick with gas. The guys I know with the older ones were getting in the low to mid 20's on the highway. I don't know anyone with a new one.

 

[Diamondpilot]

You tow 5000# behind a S70? Thats a lot of weight for a 4000# car.

Aaron Z

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.

Chris

 

[Diamondpilot]

I was planning on buying a DMAX for my next truck..If the EPA version is this bad, I'll stick with gas. The guys I know with the older ones were getting in the low to mid 20's on the highway. I don't know anyone with a new one.

Both my 05 and my neighbors 07 got right at 20, maybe 21 on a good day with our Dmax. I do not think that is common anymore. My friend has a 08 2500 4x4 and he gets about 16 at best.

Chris

 

[Dargo]

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. It's not absolutely huge by any real measure, but it is a 9.3 liter engine that weighs about 1700 pounds. I do have the 6 speed Allison engine coupled to it and it only turns about 1500, or so, RPM at 70 mph. The part that gets me is that the aerodynamics are about as bad as you can get and I'm always towing at least a 4000 to 5000 pound vehicle behind me.

If they can get that MPG with something that big and heavy with no aerodynamics, why do I only get about 1 mpg better with my F350 when pulling around 16,000 pounds? It's only a 6.0 liter engine and it has a lot better aerodynamics and weighs a huge amount less. Man am I confused. Maybe I ought to look for one of those big RV coaches that has had the body destroyed on it but still has a good C9 engine and Allison drive train. It would have a heck of a lot more power, a B50 life expectancy of 750,000 miles and get better MPG with a little aerodynamics. Heck, it might be neat having a pickup with a 30' long bed.

 

[timswi]

Both my 05 and my neighbors 07 got right at 20, maybe 21 on a good day with our Dmax. I do not think that is common anymore. My friend has a 08 2500 4x4 and he gets about 16 at best.

Chris

I get 17 MPG with my 04 GMC 5.3 w/3:37's ...And I beat this thing hard. 80+ MPH on the interstate and running the other half of my 60 mile round trip on windy country roads....What is the EPA doing here? Good grief, my '89 3/4 ton 6.2 diesel Suburban did better than the new diesels. No win I see.

 

[aczlan]

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.

Apparently, I was being generous with the vehicle weight (at least for a US spec '98 S70), it is listed has having a curb weight of 1454kg (3198.8 pounds) and a max GVW of 1900kg (4180 pounds). Dad had one of those with a Turbo in it and it squatted with a 3500# equipment trailer behind it. IIRC, the US spec ones aren't rated to tow more than 3500# (1500 wo/brakes).

I suppose though, that a 5000# dual axle trailer behind an S70 wouldn't be too bad as long as it had decent brakes on both axles and the load was properly balanced.

Aaron Z

 

[brain55]

10-12 mpg towing 17-18 unloaded would be awesome. Beats the heck out of 5 mpg towing and 9ish unloaded.

87 octane unleaded around the corner from my house is $3.13/gallon
diesel is $3.25/gallon

Theorectically my fuel bill could go from $1000/month to $520/month.
I realize the diesel is a little more to maintain but a truck with 200,000 miles on it is not exactly cheap to maintain either.

I know my wife will exercise her veto power, and I agree. Even though on paper it would probably only be a couple of hundred dollars more a month for a new truck, I will wait until next year. It will give us a chance to pay down some other bills before I pop for a $55,000 truck.

Brian

 

[Dano5509]

I have a 2005 Silverado 3500 SRW Long Bed Crew Duramax/Allison. It has an AFE Stage 2 air intake/filter and pulls 18mpg with the 3.73 gearing and an empty bed. Pulling our Jayco Eagle 5th wheel at 10k lbs it goes down to 12.

It does not have the DPF and I am going to put a 4" MBRP downpipe-back exhaust on it soon and maybe a Max Energy tuner. I don't want to wind the Duramax up too hard and will try the tuner on the 1 or 2 setting to see how much of an improvement I get with the cold air intake/exhaust/tuner.

Xtreme Diesel Performance has some interesting "kits" available for the DPF equipped trucks...

 

[Ford tractor]

Every year the duramax has gotten more HP and less mpg. This year's version has tons of power and the lowest economy yet. I drive an older LB7 version and get 18-20 empty and 12-14 towing 10k (tractor).

Given the $10,000 premium for the diesel, I'd just get the gas engine in a new truck. The new anti pollution solution scares me. I've heard DPF's out of warranty will be $1000-1200. Who knows what the urea systems will do. Plus the new gas engines are much more economical and powerful than the old ones. There is no longer a clear justification for diesel unless you run 40-60k a year loaded.

 

[Renze]

You tow 5000# behind a S70? Thats a lot of weight for a 4000# car.

Mine is a first generation S70 (basically the facelifted 850) which weighs 3200 pounds, and i've towed 6 silage bales with it, about 7000 pounds loaded. At that weight, wheelbase of my trailer, and height of center of gravity, its better to take the small roads and not exceed 60km/h because its clearly way beyond a point where i would let others drive.

The time i towed 5000 pounds was a long wheelbase 20ft tandem, which is more stable than my own 12ft tandem. We took a tractor home with the cruise control at 115 km/h, so it could run in 5th gear at the engines "sweet spot" , max torque at 2200rpm.
I'm thinking of installing HD rear springs of a V70 estate to increase the stability, to be able to tow bigger tractors every now and then, and to increase the hitch load from 75 to 150kg, when towing 5k lbs.

I suppose though, that a 5000# dual axle trailer behind an S70 wouldn't be too bad as long as it had decent brakes on both axles and the load was properly balanced.

With the tractor i stopped twice in the first 2 miles to roll the tractor back and forth to reach optimum weight distribution before i hit the highway. The trailer was a 3.5 ton (7700 pounds) with two 1800kg axles with surge brakes. When properly maintained (the brake bowdens need replacing at least every 5 years, or 2 in commercial use) the trailer will smoke its tires when you hit the brakes hard.
By law, in Europe everything has a brake force which equals 45 to 55% of the weight on the axle. at my former employer we allways liked to stay above 50% because bowdens start to brush off after a year or two and the friction in the cable reduces the brake force.