Diesel Mileage

[Rimrider23]

I recently pulled a new F.R. Sierra 377FLIK with a 2012 Ram 3500 dually diesel 4x4. It has the 6.7 motor with a 3.73 rear end. Used the Andersen fifth wheel hitch, it worked great pulling the 13000 lbs. plus, trailer and load. The truck pulled great, everything went well. Except, I'm a little disappointed in the mileage I got from the trip. We traveled about 160 miles, and the truck averaged a little over 10 miles per gallon. When I travel without the trailer, I'm getting 13.5 miles per gallon on the highway. Is this the mileage that I can expect from this diesel? Is there anything I can do to increase my mileage results? I will admit, during this trip, a couple of times I pushed the throttle up to 80 mph to get by slower truckers. I'm sure that didn't help. But anyway, does anyone have any suggestions?

[ependydad]

I have a 2012 Ram 3500 Dually 4x4 with 4.10 gears. I have 36,000-ish miles on the truck with 12,000+- of them being towing miles. My fifth wheel seems to be similarly sized- 42', 13' 4" tall, and weighing in around 14,000-14,500 pounds.

Your numbers are pretty close to the numbers that I tend to get. I hand calculate almost every tank (there's an app for that). When I'm estimating trip costs/budget, I plan for 9 mpg towing. My non-towing numbers range from 12-15 (though, 15 is rare) mpg depending on the kind of driving I'm doing (highway vs. around town).

I keep hearing that diesels get better mileage as they break in. It's gotten slightly better, but still lower than I'd like. I haven't played around with any ways to increase it.

[mcnabbwr]

I believe that any of the big three diesels will perform about the same. I average around 10 towing and 13-14 empty with my Ford.

[TURBS]

Tuned and modded 08 duramax.
9-10 towing 14,000 lbs.
11-12 towing 7,000 lbs
19-20 not towing

TURBS
08 duramax tuned n modded, 32bhok Sabre
2015 camping "2 nights"

[elind]

I just came down this winter from Upper Michigan to Arizona. I pulled a Wildcat 327ck that loaded is about 12,000lb with a GMC 2500 Duramax. Without the RV it gets 20-22 mpg and with the 5er I got 8-11 mpg coming down. In the stormy, windy winter travel the best I could get was 8-9mpg using a winter blend fuel. Along the way in New Mexico the mileage jumped up to 11mpg but it may have been because of the different blend fuel. My dream is 9-12 mpg when the D-max is broke in.

[bbritt18]

[QUOTE=TURBS;827686]Tuned and modded 08 duramax.
9-10 towing 14,000 lbs.
11-12 towing 7,000 lbs
19-20 not towing

My numbers are almost exact to Turbs,

[Krawler]

Tuned and modded 6.7 Cummins, 20-25 highway, 14 towing (summer fuel), 10 fully loaded to Daytona with (winter fuel additive).

If you are up north, the additive they put in the diesel to prevent gelling, will drop your mpg 2-4/gallon. I notice this even more with the car TDI.

I agree that a diesel does not really break in until you hit 100,000 miles and your mpg will get better .

[Tonkatoy77]

Mine is a 2007 Duramax tuned with EFI Live. I have a 8" lift with 36" tires. The heaviest I have towed is 8000#'s. I get 10mpg towing. Empty hwy I get 17-20, depending on the terrain. Around town I get 14-15.

I am guessing if you tuned yours and got rid of the DPF and EGR, your numbers would really increase. That is, if you can get away with it.

[TURBS]

Op is in mo. So shouldn't be a problem

TURBS
08 duramax tuned n modded, 32bhok Sabre
2015 camping "2 nights"

[BombDoc]

Originally Posted by Krawler

Tuned and modded 6.7 Cummins, 20-25 highway, 14 towing (summer fuel), 10 fully loaded to Daytona with (winter fuel additive).

If you are up north, the additive they put in the diesel to prevent gelling, will drop your mpg 2-4/gallon. I notice this even more with the car TDI.

I agree that a diesel does not really break in until you hit 100,000 miles and your mpg will get better .

My numbers are identical. No worries of fuel additives down here in the south.

[extremebike]

Yep. The mileage goes off a cliff after 60 mph. The only thing that makes the mileage worse is stop and go traffic.

[wire1946]

I have a 3500 Chevy 4x4 diesel and it get on road pulling my C C 38FL is around 16500 I get about 10 -12 .just on road 65 mph I get 20 mph.

[Jim34RL]

Originally Posted by Rimrider23

I recently pulled a new F.R. Sierra 377FLIK with a 2012 Ram 3500 dually diesel 4x4. It has the 6.7 motor with a 3.73 rear end. Used the Andersen fifth wheel hitch, it worked great pulling the 13000 lbs. plus, trailer and load. The truck pulled great, everything went well. Except, I'm a little disappointed in the mileage I got from the trip. We traveled about 160 miles, and the truck averaged a little over 10 miles per gallon. When I travel without the trailer, I'm getting 13.5 miles per gallon on the highway. Is this the mileage that I can expect from this diesel? Is there anything I can do to increase my mileage results? I will admit, during this trip, a couple of times I pushed the throttle up to 80 mph to get by slower truckers. I'm sure that didn't help. But anyway, does anyone have any suggestions?

First off you need to understand the emission requirements of your truck. To help keep the DPF clean the engine will use fuel to burn off soot in the DPF. This will lower your fuel mileage since it is being injected after the power cycle of the engine and into the exhaust stream. This is done about every 180 miles or so especially when towing and working the engine hard. So your fuel mileage suffers and than you are pulling a 13ft sail down the road this too uses fuel. 10 MPG is about right for your truck when towing.

The newer Rams say from 2013.5 and on will have better fuel mileage due to the redesigned of the emission equipment and using DEF to clean the DPF instead of fuel. Which improves the mileage but not much when towing.

[Krawler]

If you can still find a programmer that is compatible with the DPF Deletes, get all that emissions crap off the truck. It will run better, improve the mileage and add life to the motor.

EPA was cracking down on the programmer companies. They could sell what they had, but could not continue to manufacture new units. Out if the loop now, so not sure what the current situation is.

[TURBS]

Originally Posted by Krawler

If you can still find a programmer that is compatible with the DPF Deletes, get all that emissions crap off the truck. It will run better, improve the mileage and add life to the motor.

EPA was cracking down on the programmer companies. They could sell what they had, but could not continue to manufacture new units. Out if the loop now, so not sure what the current situation is.

Sold as "for off road only"

TURBS
08 duramax tuned n modded, 32bhok Sabre
2015 camping "2 nights"

[BigTJohn]

My '14 3500 dually gets a solid 12 when towing (avg for 9k trip to WA from FL and back) a 14k Columbus. I never go over 60 mph. Anything faster than 65 is stressing the tires and you never get back damage done to them over 65 by traveling less than 65. With no tow, I can get 19+ mpg but at 70 mph, around 17-18.

[whitca]

Originally Posted by Krawler

Out if the loop now, so not sure what the current situation is.

EFI live to tune for deletes now. I switched from my H&S "off road" minimax (once I heard their service dept dried up due to EPA constraints) to EFI live tuning and actually picked up 2 mpg in city driving. I haven't had the chance to see if there are any gains towing but am looking forward to it.

[mud yapster]

My old Ford F350 7.3L Lariat 4X4 gets 9 to 11 mpg towing 16,000 lbs. Palomino Columbus up and down these little East Texas hills depending on wind direction.

[Krawler]

I have the EFI Live too and live it!

[StoneyG]

We have a 2012 pulling an 18-19 GVWR fiver and get about 9-10 pulling and average about 18 not pulling. I can get some sustained dash readings of 21-22 at 55-60 on the highway. I don't drive over 60 pulling.