Fuel economy with a diesel truck ?

[Diamondpilot]

Thanks for yanking my chain. This new computer has a spell checker that works overtime and likes to find other words and finish my typing for me. My last trip was 23 mpg. It was all highway to the In Laws about 240 miles round trip. I live 3.5 miles from the highway with one stop and they live about 5 miles from the highway with three stops. I do have the truck modified with a Chip, Larger Exhaust, and High Flow Intake.

Chris

 

[Builder]

JB I agree with ya 100%, That Builder guy does know his stuff !
Thanks Builder
Jim

Anytime!

 

[NJDiverDan]

I have an '03 dodge with the HO cummins and an auto. 3.73s in the rear. I have 170,000 and average around 20-21 with hilly country driving. I used to do more highway driving and going 80-85 I would get around 19-20. The sweet spot for this truck is to keep it at 65 mph. I was following my friends pulling trailers and had the cruise set at 65 for the day, got 26 mpg for that tank.

Pulling a 6000 pound boat I get 16-17 mpg.

-dan

 

[Builder]

I do have the truck modified with a Chip, Larger Exhaust, and High Flow Intake.

Chris

Why do you need to do that?

 

[Iplayfarmer]

This may or may not be relevant, but I drove a '93 Dodge 3/4 ton with a cummins in it for my job when I was in college. I don't know what it had in it, but it looked like it had been wrecked a few times and it pulled like a workhorse.

My job was hauling pigs to the slaughter house. I'd drive about 1/4 of the way empty (driving to and from the farm where the trailer was), 1/4 pulling a fully loaded gooseneck trailer (hauling to the packer), 1/4 hauling the empty trailer back, and the other 1/4 was usually driving around town running errands for myself and for the farm.

I filled the truck up at only a few gas stations, and I checked the mileage every time. I got a steady 24 MPG. At the time I just thought that was what diesels got.

Most of that was highway driving during the construction through Salt Lake City in preparation for the Summer Olympics. I'd negotiate the mountain pass from Ogden to Logan about once a week too.

 

[Diamondpilot]

Why do you need to do that?

Here we go again...LOL I am convinced it makes a difference plus it makes the truck a lot of fun to drive. Do I need it, no. I sent the chip in for my F-350 to have it detuned slightly and it was gone for 2 weeks. I lost 2 mpg. They do more than just dump fuel in.

Chris

 

[Builder]

Here we go again...LOL I am convinced it makes a difference plus it makes the truck a lot of fun to drive. Do I need it, no. I sent the chip in for my F-350 to have it detuned slightly and it was gone for 2 weeks. I lost 2 mpg. They do more than just dump fuel in.

Chris

Ah, OK. Most guys with 6L's modify them to keep up with the new trucks power output. Amazing how a product can dump more fuel in an engine AND decrease fuel consumption.

Just messin

I'm real happy I finally have a truck with enough stock power output to make it fun to drive and pull anything I put behind it without worrying about voiding my valuable powertrain warranty.

 

[Diamondpilot]

Went with my neighbor today to pick up a Lincoln Aviator he had bought in Detroit. The trip was 441 miles from his drive to Detroit and back to his drive. It was raining and windy the whole way but that is another story. We filled up 3 miles from our homes and again at the same station on the way back. His 2007 GM 3500 4x4 Dura Max with the 6 speed Allison and 3.73 gears pulling my 18' car hauler empty up and with the SUV on it back did this trip on 27 gallons of fuel. We ran about 70 on the highway and 55 on the state roads. It was about a 50/50 split. That is 16.33 mpg average. The trip computer in the truck said a little better but I believe the calculator. The trailer is about 1,500# empty and the SUV was 4,980# according to the internet for a total load about 6,500# in round number.

Chris

 

[jcmseven]

Chris,

That truck is a keeper. I know my 6.4L will not get that level of mileage pulling that load. Although my mileage has improved as my truck has gotten more "break in" miles, it is not at that level yet. I have not recently calculated my towing FE, but pulling my tractor/trailer combo has netted me around 13 mpg in the past. It has an approximate weight of #7000. My friend's 2007 GMC Duramax will not get that kind of mileage either. He gets a consistent 11 mpg pulling his 6500# travel trailer. It would have more poor aerodynamics than your load, but is not too square in shape. Sounds like that Duramax does pretty well on fuel. I would say, based on my limited experience, that is better than average. Although it does not happen often, some examples of each truck line will have outstanding performance like this and they should be kept and operated until they completely fall apart--or a million miles whichever comes first.

John M

 

[Diamondpilot]

My neighbor gets the same results pulling his 28' travel trailer (7,000#) with the truck mentioned. 11 mpg is all he can squeeze out pulling it. The problem with travel trailers is the back side. Yes the front is a big aerodynamic brick but the rear makes all the drag. The end result is there is not much you can do to make a travel trailer more aerodynamic. On the trip we did yesterday he was able to average about 18.5 mpg according to the trucks read out with just the trailer and about 14 mpg according to the trucks read out with the SUV on the trailer with the average being 16.33 mpg.

Chris