Your numbers are very close to what the majority of the Ford 7.3 PSD, Dodge 5.9 CTD, and GM 6.6 D'MAX diesel pickup trucks in the many forum's poster's report on average and what we have experienced also. Ford 6.0 and 6.4 PSD's and Dodge 6.7's are reporting a few MPG's less. You didn't mention your speed while towing but I'm guessing it the be in the 65 MPH range. At 55 MPH when towing the same weight as you, we get 14 MPG's plus. Our tow behind is a 29ft Carri-lite 5'er (10,800lbs as weighed) with our 2,150lb (as weighed) 16 1/2 ft boat behind. Total towed weight is 12,950lbs approx. Driving "habits" and speed make a world of difference in MPG's. Don't take your heavy foot with you, leave it home! Drive like you have "no" brakes (coast to reduce speed) unless and until they're really needed to bring the truck or rig to a stop etc. You don't really need to be the first to the top of a hill or the first to those stoplights, do you?
As for the gas vs diesel MPG's difference as reported and our experience along with my professional automotive engineering knowledge gained over 40 yrs. 2 same configuration trucks with reasonably close displacement, torque and/or HP, and driven in the "same" manner, one being diesel and the other being gas powered, will have from approx 20%-60% difference in actual MPG's. The diesel being the higher MPG's. Diesel's turn at a lower RPM rate when driven at highway speeds than does the normal gas engine. Each and every time, for a combustion to take place, there is a known minimum quantity of fuel required in the combustion chamber or it will not ignite. The more times this combustion takes place in each cylinder in these comparable "sized" engines per distance made good, the more fuel (quantity) is actually consumed. Perhaps for a mile distance since that's how most of us measure travel.
The gas engine is more efficient at higher RPM's and the diesel engine at lower RPM's. Also bear in mind that diesel fuel contains approx 11% more BTU's per measure than gasoline. Therefore diesel fuel has an 11% advantage to start with. 2 additional reasons the diesel engine is more efficient than the gasoline powered engine is because of the lower RPM's, there's less waste of energy to spin the engine fast and because a diesel runs in "oil" which lubricates and reduces moving or sliding component's friction, less energy is wasted. This also is what makes the diesel engine have a considerably longer service life. Gasoline doesn't have lubricating properties when between moving metal surfaces and actually becomes somewhat abrasive. Ever try running an oil mix 2 cycle engine without adding the oil? Doesn't run long at all before you get to buy another engine. Hey. it's only money!!!
2004 Chev 2500HD D/A crew cab LB 4X4 - Air Bags - Loaded
915 Lance Camper with 2'X 8' rear porch (my own design n build)
29 ft Carri-lite 5th wheel - 1 large slide - specially built
36 ft Carriage - 3 axle 5'er -NOW SOLD- Looking at some new 5'ers
The gas engines have much beter wear now than they did several years ago. I tore down a 97 Vortec 350 with 155,000 miles on it and was surprised by the condition of the engine. I could still see the factory cross hatch bore and there was no lip at he top of the cylinder. There were no oil deposits or sludge anywhere in the engine. If I had not spun the bearings (my fault not the fault of bad engineering I had it tuned for the cam and other mods and I had the rev limiter and shift speeds pushed up a little, when it kicked out of 3rd into 2nd at 68 mph it yanked the bearings out of the motor) anyhow it was almost as clean as it was after I had it sonicated and painted at the machine shop. I also had a 1987 Suburban with a TBI 350 that had 220,000 miles on it had never been rebuilt and didn't burn any oil between changes.
Gas engines do not have the same longevity of a diesel but they have a much better life than years ago. I remember my old 60's to early 80's vehicles were due for a rebuild a few miles over 100,000 miles.
I guess it depends on how much you want to spend on the truck and the fuel compared to how long and how many miles you will put on the truck. If you are like me and barely ever keep a truck or car for 3 years the diesel is not worth it. But if you are a 10 year kind of guy with you trucks then the diesel may be more to your benefit. I buy premium cheaper than diesel. The diesel use to be cheaper than gas and who knows it may change again. I am dreaming of a D'max but economically for me it isn't feasible. But then I guess RV'ing isn't either.
OleMissTailgater wrote: I am just looking for some real MPG info on TV. I want to know what the 3/4 ton gas or diesel trucks are getting while towing and not towing. I am thinking of upgrading into a 3/4 ton but I use my truck for work everyday so I don't want to buy something that gets 10mpg in the city. Thanks for the info.
OleMissTailgater,
The 'older' gen diesels generally got better MPG's. The newer gen versions especially the new 6.4L PSD are getter worse MPG's...all that power and smog controls comes at the cost of MPG's.
The lower power output non-smog motors of the past got the high numbers.
Take a gander HERE for the 2008 Popular mechanics shootout of the NEW diesels all duallys BUT the GM.
6.7L Cummins 13mpg non towing on a 500 mile loop and 8.7mpg towing.
6.4L PSD 11.2mpg non towing on a 500 mile loop and 7.6mpg towing
6.6L Duramax 18.3mpg non toiwng on a 500 mile loop and 10.6 towing
So an independent source tested on a real world 'drive' and got these pretty low numbers IMO...
For comparison my V10 and 4.30's towing 9000#'s over 5000 miles averaged 8.2mpgs this year and cost a whole lot LESS when I bought it.
The new 3V V10 makes more power than my 2V version and should be given a serious look today given the newer diesels initial higher cost outlay and obvious poorer mpg performance due to the smog controls...but that's just my opinion...take it for what you paid.
Photog101 wrote: 1996 Dodge 2500, EC, 360 Gas, Auto, 3.55 gears,4X2, 17-19 MPG highway empty, 8.5-9.75 highway towing 8.5' X 24' 10,000# enclosed trailer. Changed to 3.9 gears and 16-17 MPG highway empty, 9.5-10.5 highway towing same trailer. Was much easier towing with the 3.9 gearset.
Those highway numbers are impressive for an old 360. I have owned two of them, a 99 Ram 1500 4x4, and my current 95 Ram 1500 4x4. The best I have ever seen on the highway,not towing so far is 14 mpg. I get between 8 and 10 mpg towing the TT below. I see yours was a 4x2, so that undoubtedly helps your mileage versus my 4x4s, but I didn't think it would be that much.
2005 Surveyor SV-291 Tows smooth as silk!
1995 Dodge Ram 1500 Laramie SLT 4x4 5.9L V8 low miles, It ain't pretty, but it's paid for!
The highest I got towing to Florida and back last week was 7.8. I don't want to talk about the drive home with 20 MPH headwinds. It was difficult. Shell seemed to have more power than Chevron. None of the pumps were labeled with etoh content.
How much do you suppose the 12' Portabote on my roof rack hurt my mileage?
Towing 4 bodies in truck with a loaded 5000lb trailer.
12.6 mpg
I typically tow in British Columbia in the Cdn Rocky Mountains...ergo the low mpg. (sic)
Quote: The 'older' gen diesels generally got better MPG's.
I defintely agree with that statement. My old 6.2L GMC got close to 29 mpg..but no turbo & no injection and not a lot of power.
Now one thing I gotta say. I do not believe for a moment that weight is the primary issue facing trucks towing. It is relevant, but not the major limiting factor. It is the size of "sail" that the front end of the trailer presents to the wind along with ones speed that really will determine ones mileage while towing.
Still I find that the newest Dodge Cummins with the 6 spds and the Dmaxes get pretty good mileage for 7000lb trucks.
cheers,
stk
* This post was
edited 01/05/08 11:52pm by Steak2k1 *
Teresa-Meagan-Kaylee '06 GMC DMax CCSB w/a lil 'Xtra Jam 2006KZ KY-Yachty CT22 done comfy.!
Reese 750WD w/DualCam Sway: 50W Solar
Aerodynamics has more to do with my mileage than the weight. My TT had more wind drag than my 5er yet it was over 3,000 lbs lighter when loaded. The trucks best mileage pulling the TT at 65 mph in OD was 8.5 mpg. The 5er which is heavier and longer I have got as well as 11.2 mpg but average around 9.5 mpg. With the frontal space of the 5er being reduced from being over the bed of the truck makes a huge difference over the TT front wall that is so far behind the cab of the truck catches much more wind and provides more drag.
Carl_722 wrote: Aerodynamics has more to do with my mileage than the weight.
Carl,
Your observations have been my observations with regards to aerodynamics vs weight...
What was very interesting to me is that if you notice in that Popular Mechanics article I linked to just above...the 9200# trailer they used for the test tow as an open utility trailer pulling a medium track driven earth mover. The trailer weighed ~3000 and the mover ~6000...so aerodynamics played a very SMALL part in the published numbers in that article...I too went hmmmmmmm.......
As for the gas vs diesel MPG's difference as reported and our experience along with my professional automotive engineering knowledge gained over 40 yrs. 2 same configuration trucks with reasonably close displacement, torque and/or HP, and driven in the "same" manner, one being diesel and the other being gas powered, will have from approx 20%-60% difference in actual MPG's. The diesel being the higher MPG's. Diesel's turn at a lower RPM rate when driven at highway speeds than does the normal gas engine. Each and every time, for a combustion to take place, there is a known minimum quantity of fuel required in the combustion chamber or it will not ignite. The more times this combustion takes place in each cylinder in these comparable "sized" engines per distance made good, the more fuel (quantity) is actually consumed. Perhaps for a mile distance since that's how most of us measure travel.
A 20% to 60% spread in mpgs for gas vs diesel is pretty wide in a technical comparison. Can you narrow the spread down a bit?
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