Fuel Mileage !!

[dezldog1]

Another newbie question

We have a new 2010 Dodge Ram 2500HD diesel. The fuel mileage is not good to say the least. Will this get much better as the engine breaks in ??
Does anyone know what the average mileage pulling a 35' 5er may be ??
I know this is a bit of a stupid question but never pulled such a large trailer before. Just wondering what the worst and best scenario may be?

Regards
Jo

[great white]

Maybe define what "not so good" is for your current mileage and how many miles on your truck's odometer so far.

My 98 K2500 GMC gets 11-13 Mpg pulling our 35 foot 2011 831RLBSS.

Lots of things are going to effect your mileage when towing.

For example:

Headwind/tailwind
Terrain
Temperature
Driving style
Speed
etc.......

[rthrbelsewhere]

Summer fuel, outdoor temps above 50*, pulling my little Roo over 4 mountain passes from NE Colorado to SW corner - average 13-15mpg. Empty with no trailer, average 17-19mpg. I use a phone app to track my fuel mileage to see if it gets better or worse depending on the fuel type (winter time - they mix #1 with #2 diesel), outdoor temps, and load.

Unlike a gasoline engine, a diesel would not get better fuel mileage as it breaks in. They do say to not pull anything for the first 250 miles, but after that, you should be good to go. I owned a 6-speed manual 2004.5 that averaged about 1-2 mpg less than the automatic 2006 that I have now.

I would also recommend taking a look at cumminsforum.com and maybe post this same question in there. You will probably have more responses from the 2010 Cummins owners than you would in here. I think a big reason why the 07.5's and newer get a lower fuel mileage is due to the exhaust system that they put on it to meet the new requirements, more details about that in the cumminsforum.

What are you experiencing for fuel mileage in your 2010?

Joe

[dezldog1]

Right now city driving in cold weather approx. 10 mpg. There is approx 3500 miles on the engine

[donn]

First off that is way too much trailer for a 2500 series truck.
Now that I have that off my chest you can expect pulling that heavy to get maybe 7-9 towing. 13 in town and depending on axle ratio maybe 15-16 empty on the highway. It all really depends on what speed you want to drive. Pull at 55 and you can expect a 20% increase in fuel economy over pulling at 65-70.

[rthrbelsewhere]

Yea, I would bet that part of that is due to the winter fuel, topped with outdoor temps, the engine is just not as efficient as it would be with summer fuel and outdoor temps at least 50* or above. One thing that you'll want to do, if you haven't already, is install a EGT (Exhaust Gas Temp) gauge with the probe before the turbo so that you know what kind of temps you're pushing out while you're pulling. Keep it under 1350* or you could cook your pistons.

I agree with Donn on the 55mph vs 65mph fuel mileage. I actually watch my RPM's closer because anything over 1800 rpm and your fuel mileage starts to drop dramatically. The sweet spot on the cummins I think was around 1500-1600 rpm, where you get the most hp & torque for the bang.

[dezldog1]

Thnx guys I sure appreciate all the information.
You're awesome :-)

[jcts43]

I have a 2001 2500 Dodge Cummins. This the first year they were made with 24 values. I pulled a 30 ft Nascar vendor trailer all over the country. I also have a Edge 65 box in it. This is the one that is not adjustable. The truck alone gets between 21 and 22 mpg. That is according to the computer on the truck. I run sytheic oil in all the gear boxes. That is rear end, Auto Trans, and Engine. The trailer loaded weighs between 7,000 and 8,000 lbs. If I stay around 65 mpg, I am getting around 14 mpg.
That will vary depending on hills, mountains, and head wind.

[rthrbelsewhere]

As far as the overhead computer in the 3rd generation Dodges, don't bother calculating mpg with what it has to say. That overhead has never been correct in the 108k miles I've driven mine and if it was accurate, I would be getting 23-25mpg all the time. I've tracked my fuel efficiency in a phone application called "mileage" for the last year and I've never come close to that. If anyone wants to find an accurate reading, it's a real p.i.t.a., but you'll have to control a hand full of variables while recording the odometer and fuel volume. Those variables being the fuel station, pump location, vehicle position, maximum fueling point...all needing to be exactly the same each time you fuel up and record your data. Anything outside of that will skew your data and give you inaccurate results.

[bailer6334]

I average 10MPG towing at 62-65MPG, 14MPG city driving not towing. I loose 2-3MPG because I have a dually and 4-wheel drive. My truck has a little over 58k on it. Two comments. As stated above you should be using a 1 ton, and it would have been wise to inquire about mileage before you purchased the truck. From what I've heard and read all three (Ford, GM & Dodge 2011 models) get around the same towing. Its not towing where GM and Ford in the 2011 get far better mileage than Dodge.

[KyDan]

I get 9.5 to 10.5 mpg.
It sucks IMO

[Herk7769]

We just completed our second year towing the 2010 Flagstaff 8526RLWS 5th wheel with our 2008 GMC Crewcab 2500HD with Duramax/Allison 3.73RA.

Truck unhitched weight loaded for camping (includes Yamaha 3000 generator w/3 gallons gas; 10 gallons diesel in 2 plastic cans; 2 - 2.5 plastic gallons gasoline; 3300 sliding hitch; pancake air compressor hoses and fittings; 8 - 2x12x12 PT wood leveling blocks; two mountain bikes on the front of the truck in a receiver hitch; wife and dog = 7800 pounds.

Camper loaded for camping disconnected = 9150 pounds.
About 1350 rides on hitch when connected.

No wind mileage:
Mileage at 55 = 13.5 MPG
Mileage at 60 = 12.0 MPG
Mileage at 65 = 11.0 MPG
Mileage at 70 = 10.0 MPG

Since someone posted empty MPG I will add that I typically get 13.5 average "around town" a mix of highway and mostly stop/go. On the highway, with me and the DW, I drive 60 with speed control and average 22-23 MPG

[dezldog1]

Thank you for all the great information. Again.... you are all awsome !!
Very helpful :-)

Regards
Jo

[jimh]

i pull a cardnal 33 ts that weighs 10400 dry. on level ground at 70 mph, i get 8.3. at 50 mph, i get 10.1. i'm running the 2002 F350 7.3 diesel.

i use a calculator to figure my mileage. sense diesel foams, it is better to figure it over several tanks. unfortunately, mine are calculated on a single 40 gal tank.

the part i don't understand is that i get better in hilly areas (what i call mountain). believe it may be because i drive slower.

[Herk7769]

Any pilot will tell you that when "drag" is involved, slower is better.
In the C-130 world, we airdrop heavy equipment using a giant parachute that we deploy from the back of the plane. That parachute pulls on the pallet that has the equipment on it. When it inflates it tries to stop the aircraft in flight, but since it is attached to the pallet; it just stops the pallet. We fly away from the stopped pallet and chute. It is a wild ride, let me tell you seeing that tank or truck get ripped out of the plane.

Why I mention the story is what we do if there is a malfunction and the truck or whatever DOES NOT MOVE. WE STOP. Airspeed will rapidly decrease until a point where engine power will offset the drag from the parachute. The slowest we can fly is the point of lowest drag from the chute; so we slow to 10 mph above our stall speed.

When towing, the trailer is the parachute. The faster you go, the higher the drag from the air hitting the trailer and vehicle and the more engine power (higher fuel use) to keep you at the speed you are traveling at. The formula for drag has an "exponent" in the velocity term. That means that increasing your velocity by 10% has a MORE THAN a 10% impact on your fuel use.

Slow down and save gas. 60 MPH seems to be the sweet spot for us. We could get better gas mileage at 55; but 60 MPH is 1 mile a minute and it makes figuring out how long we have to go till the next town so much easier.

[great white]

Hey herc, that's the first time I've seen someone use a lapes drop to describe trailer aerodynamic drag!

[Herk7769]

Well, LAPES (Low Altitude Parachute Extraction) is a whole different ball game in the "risk mode". I hated that qual with a passion and was super glad when they did away with it. I was describing Heavy Equipment Platform Airdrops.

The technical term for drag associated with speed and frontal area is Parasite Drag. Drag associated with the manufacture of LIFT is called aerodynamic drag. The two together are summed to create total drag.

An aircraft flies by using power plus lift to exceed weight plus total drag.

Use enough power and you don't need lift. F-22 prime example. It can "hover" on its exhaust plume.

In any case slower is better when you are working in 2 dimensions. Since you don't need to generate lift, parasite drag and rolling friction are the only thing you have to defeat with power to move on down the highway. If it were not for drag and friction, you could give your truck and camper a good shove and throw out an anchor when you got to the camp ground.

[shineysideup]

Originally Posted by herk7769

In any case slower is better when you are working in 2 dimensions. Since you don't need to generate lift, parasite drag and rolling friction are the only thing you have to defeat with power to move on down the highway. If it were not for drag and friction, you could give your truck and camper a good shove and throw out an anchor when you got to the camp ground.

This is almost exactly how the dealer I bought from explained it. He said that if I put a 10,000 lb. load with wheels behind my vehicle I would be able to drive away (in the simplest terms...), put an 8' diameter parachute behind my vehicle and look out! This is why the shape of the trailer along with the weight is something one must consider. The type of suspension and floor plan can also play a role in how easy a trailer pulls. Think airstream, love them or hate them they do work. We are starting to see some company's taking aerodynamics into consideration, and not just at the front of the trailer ( rear end, integrated awnings that look like roof rails etc. ).

[great white]

Originally Posted by herk7769

Well, LAPES (Low Altitude Parachute Extraction) is a whole different ball game in the "risk mode". I hated that qual with a passion and was super glad when they did away with it. I was describing Heavy Equipment Platform Airdrops.

The technical term for drag associated with speed and frontal area is Parasite Drag. Drag associated with the manufacture of LIFT is called aerodynamic drag. The two together are summed to create total drag.

An aircraft flies by using power plus lift to exceed weight plus total drag.

Use enough power and you don't need lift. F-22 prime example. It can "hover" on its exhaust plume.

In any case slower is better when you are working in 2 dimensions. Since you don't need to generate lift, parasite drag and rolling friction are the only thing you have to defeat with power to move on down the highway. If it were not for drag and friction, you could give your truck and camper a good shove and throw out an anchor when you got to the camp ground.

I might be sandbaggin' ya a little bit. I have a bit more knowledge of aerodynamics and air ops than most:

[Herk7769]

Nice! Then you know that NONE of that aerodynamic discussion applies to you. Helicopters do not fly using principles of aerodynamics. They just BEAT the air into submission.