I took a 2005 2500 cc sb cummins out for a test drive towing a 9,000 lb trailer,filled the truck to the brim went 180 miles, filled fuel tank to the brim again and got 10.98 mpg now this truck is bran new maybe 250 miles when I started and had about a 30 mph tailwind going and 30mph headwind comming back. Then when I got back I hooked up my 2002 2500 hd extended cab Duramax and filled it to the brim, then went about 50 miles towing the same trailer, headwind about 15 to20 mph now , 25 miles into it and 25 miles with it. Filled up and got 11.88mpg. These are hand calculated figures, my question is will the dodge cummins increase enough to get better than the Duramax. I,am looking at Dodge only because of my poor fuel mileage with the Duramax. Thanks

 

when I pulled off the lot I was getting about 15mpg. now after 22k that number is steadily approaching 20. this is unloaded.

pulling 8k I got about 13 or so, but that was the overhead and since I didnt pull it for a full tank I'm unsure of the true mileage. But I can say that the cummins will live longer and happier with a load on it's back.

 

I'd at least say that there's no way your wind calculations can be accurate. Headwinds and tailwinds are rarely steady in direction or speed and will greatly affect the outcome of the tests. The only way to test accurately is to do it on a calm day.

 

I just pulled a 7'x16' HD trailer with my car on it from Ft Benning Georgia to Aberdeen Maryland and averaged ~15 mpg. My truck has the 6spd tranny which apparently gets the worst mileage and it was full of my housewares. The truck only has 10K miles too.

 

I get around 11 towing a 32 ft fifth wheel weighing around 10k going about 75-80. I'm sure if i slowed down a little it would help to. But overall I'll take a cummins for towing over a duramax anyday. Headwind or no headwind.

 

My father has a 04 3500. He gets about 14mpg pulling a 28ft 5th wheel. 20K combined weight between truck and trailer doing about 70mph. Oh, he does have a 100hp chip and intake also.

 

I just got back from an 850 mile trip in my 'new to me' 2003 305hp diesel pulling a 7,000lbs trailer. On the overhead, 12.3mpg and that seems about right. On the trip I went from 800feet above sea level to 9,000 feet and back cruising along at 69mph most of the way.

 

2005 Ram 2500 QC with 6.25' Bed pulling 2000 lb trailer with 4000 lb Jeep and carrying 1500 lb pickup camper on 300 mile round trip averaged 13.1 MPG. The trip included 75 MPH interstate driving and 60-65 MPH highway driving with slow-downs and speed-ups for small towns as well as some pretty good rolling hills. I had less than 2000 miles on the odometer.

 

i am new here and need some questions answered PLEASE answer honestly. We have a 2005 F-350 King Ranch loaded with every available option except the trailer brakes. We have put straight exhaust and an airraid intake for better gas mileage and nothing helps. My worst is 8.5 towing a light load that my 2005 tacoma pulled and got 19. myh best has been 15 at 65 with a tail wind. I am seriosly considering the mega cab with the cummins or even a quad cab. We keep getting told that it will get better with miles the truck has 40,000 and no better. my old PS got an average of 19 to 20 best of 22. My 92 cummins got 27 empty and 24 loaded. We are scared about spending the money for no better mileage. My tacoma can pull 6500 pounds and get around 15 worst and 26.2 best empty.

 

the 6.oh-no's get horrid fuel mileage mainly because they rev sooooo high to achieve the HP and torque needed. the older 7.3's which ford should have stayed with reved in the 2000-2500 range to maintain good power, the 6.oh-no's venture into the 3K range alot from what I hear, also the new duramax is rumored for 06.5 to be able to fuel to 4800rpm and make 350hp and 650tq so mileage is going to be even worse.

the cummins which not only has 40% fewer moving parts revs much lower. my engine which is still stock begins to pull hard at only 1500rpm which is where the torque begins to hit, I rarely rev over 2500. and since you have two less cylinders to worry about, plus your reving lower your fuel mileage is going to be better. also since it is an inline engine you dont have side wall loading which helps the engine live longer, also the power hits at the same spot on the crank instead of two different angles. Cummins has been building this engine just about since the company was founded and has been making improvements ever since and it is not uncommon to see these engines live past 1million miles and still go.

the heaviest Ive pulled was 8K and I averaged about 13mpg, this was also doing 70 the whole way, unloaded I get just under 20 and this is with 4.10's. Many of the other guys I know have the 3.73 rear axel and loaded with a 15K 5vr get roughly the same mileage. plus the Cummins is designed to run forever. the Marine version of this engine puts out 425hp and 910tq and the only change are injectors, fuel mapings, and turbo