[slowmover]

Welcome!

A "tuner" is not always the answer. Help can be found there, but it is cake icing when you want the recipe for the cake itself.

I want to get better MPG towing a fifth wheel trailer.

I would start with records. Filling out the requested info that others here may see your vehicle specifications would be first (as seen in sidebar). Second are vehicle records. Every gallon and every mile (fuel log). Note also engine hours as average mph is important.

Next is vehicle mechanical (as it has to be done anyway). Rolling efficiency is aided on both vehicles by:

- perfect alignment
- zero brake drag
- proper bearing adjustment
- ideal tire pressure
- wheel/tire balance

and on the TV:

- no steering slop
- fresh fluids & filters
- all book maintenance up-to-date

Even if brand new this is central to "being sure". I also acquire scale tickets as weights are a useful tool for tow rigs. Empty, loaded and separately. Best mechanical baseline.

There are now a good number of discussions of fuel economy for diesel engine pickup trucks around here that are not brand-specific. Strategies and tactics, if you will, that aid best mpg in all situations.

Next, the word "towing" used as a search term will reveal some threads and posts.

The short answer is towing speed. 58-62 mph is about it for "fast" and "good mpg". 55-mph, obviously, is even better.

Skyking has some relevant posts for you (Dodge pulling an Avion 5'er). See also posts by Kamper Bob as his rig is small, but a 5'er, and his ideas are very good reading.

And if you have any pictures of your rig, that is also good if you'd post them.

I believe there are some economy sub-forums on at least one of the Duramax enthusiast forums. But if the Dodge guys are any guide, most all of them think that buying stuff is the answer. Tread carefully as some tuners can shorten component or vehicle life or both. And some replacement parts may not add anything at all, just a bigger hole in the wallet (thus the need for records).

Fuel economy is usually a bunch of small things that add up together to make for improvements. The game is about percentage increases, not absolute numbers. And it is the average mpg through which we can show success.

You may be the first Duramax guy around here. I can't recall another right off the bat (which considering that GM configured truck is the favorite among RV'ers -- just as Dodges are for working trucks and Fords are for riding the wrecker sling -- is a small surprise as RV owners tend to be concerned over FE).

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