This is my first post. I hope I'm in the right place. I have a 2005 2500 ram pu quad cab Laramie, 5.9 cummins HO. I get about 15-16 mpg all around. I tow a 38 foot 5th wheel and get about 12 mpg. Am I getting about the noral mpg or should I try some type of upgrade to get better? (tuner or something?)

 

That's pretty standard to the higher end of the range while towing something that large I would say. Some will say they get mid 20's but I usually filter those out. You can achieve 22 probably at the best with best case scenario like flat ground no wind and running between 60-65 mph not towing. The overhead lies like a rug though so hand calculated numbers are all I would trust.

Tuners of all types including piggy back and flash units can help your mileage but they also make you a little greedy too. You can find yourself mashing the go pedal even more to exercise your new found power so your mileage suffers because of it. It's a double edged sword. lol

 

Thanks for the tip. I don't use the overhead readout for mileage. The best I've ever gotten was at 50-55 empty over about 300 miles. I am skeptical at pulling that much weight so close to the shift point at 55 because it seems to me I would be lugging the engine.

 

I've had several tuners (Banks, Bully dog, superchips) on CTD's from 2000 to my current 06'. The Banks is a great tuner and I have no complaints, but the most user friendly for me has been the Superchips power programmer. It has never caused a code of any sort. Both the Banks and Bullydog both threw codes or caused the check engine light to come on. The superchips has multiple adjustments and reads/resets codes if necessary. Provides plenty of power and is safe for towing. It really allows your truck to do what it's supposed to with ease and better mileage too. Not much but better. I average around 17.5 to 18 mpg on high RPM interstate trips and can get up to 22 or 23 running closer to 55-60 mph. Don't go crazy, just enjoy your ride.

 

Waggonhammer, your millage numbers are good. You will also find the members of this site use Smarty as the chip of choice. You should get some gauges also. I get your worry about lugging. But a diesel loves to pull. It likes low rpms. It was built to pull.

 

It is in OD, the engine is not happy on the back side of the TQ curve and neither is the trans. You need to get it into drive at those speeds.

Keep the tach over 1800 rpms for the best power and reaction to throttle input. Right around 2000 rpms is the sweet spot for BSFC on thes engines.
Under 1800 rpms the defuel ramp is pretty sharp.

Your numbers are decent and probably the high end. I can get 22 at 60 mph in high temps but it goes down from there, 16-18 mpg depending on speed and 15-17 over all is about as good as it gets without making some major changes.

A good tuner that allows adjusting timing and TQ management will help some depending on driving habits. Dependng on what trans you have it may need help when you tweak things. Aside from the former, to gain much more you would need to swap out the cam, turbo, and injector tips to make a significant impact.

 

Your numbers aren't bad, they're average. Improvements can be made but it's really about driver training assuming no one has screwed up the truck (lift kit, offroad tires, tuner, etc).

On the RV, pay attention to rolling efficiency (align, balance, max tire pressure, no brake drag) as you would with the truck.

I wrote this up on another forum, but most of it applies:

http://www.cumminsforum.com/forum/4822575-post4.html

Optimum fuel mileage will be between 1300-1500 rpm. It's possible to have better fuel economy around town than on the highway due to this and to aerodynamic resistance. So keep an open mind about how you do what you do and be willing to change.

Once I decided that 18-mpg in town wasn't good enough I made the changes over time (reading and learning) that got me recently to 23-mpg.

Keep records of all gals/miles. What you are looking for is the average mpg and the percentage changes to that which show improvement or failure.

Your numbers, my numbers, the next-guys-numbers don't matter. What does is that the 28% change I found was against my own previous best.
That's how this game is played. A lot of little stuff that adds up.

Here's the results of some records/experiments by another man:

http://www.cumminsforum.com/forum/4463162-post115.html

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