The concepts of revolutionary new engines, technology and designs somewhere down the road are wonderful, but not very useful for the several million people who already own an RV manufactured using existing technology. What I need is something that will help me improve the fuel economy on the rig that I already own (Cat 350 Diesel, 2007 Damon Tuscany).

There are several fuel additives available that make claims regarding improved fuel mileage. For instance, RxP (www.rxp.com) provides detailed test data on their website regarding tests that were conducted with the Florida Department of Transportation on 6 vehicles of various makes and models for one full year (http://www.rxp.com/department_of_transportation_test_results.htm). The fuel savings results reported in their tests indicate reductions in fuel consumption ranging from 6% TO 30% depending on the vehicle. They also reported significant reductions in the amounts of greenhouse gas emissions from the vehicles in the test.

Does anyone have any experience using and testing any of these types of fuel additives in their RV’s, and if so, what were the results? Any info would be most appreciated.

Jeff_E, welcome to iRV2.com. We are glad to have you join us here and we look forward to reading of your adventures and experiences.
I have been using acetone in both the truck and the motorhome to improve not only fuel milage but performance as well. Basicly the ratios are 3 oz./10 gal. of gasoline and 2 oz./10 gal. of diesel. Here is a link for more info Acetone fuel additive. I get about 20 mpg in the truck and almost 10 mpg in motorhome.
Good luck and let us know how much improvement you get.