Fuel Economy on F-450 28’

[rv4travlin]

Are you folks using the computer readout for you mpg or actually manually calculating? All the computed mpg's on my vehicles over the years have been off pretty bad. Hand calculate your mileage for true mpg. (It may bring a tear to your eye when you see the real mpg).

I manually calculate.

 

[XC Couple]

I now have a 2006 Winnebago Aspect (30 ft. with the F450). After closing the deal, I drove it home from the Charlotte, NC area to Southwest VA, (about 200 miles), with a few mountains climbed in between. I got 9 mpg. It may have helped that it is a more streamlined front then some and there was little wind. Also, I travelled with no gear. If I get personalized tags on it they'll probably read "0-MPG" or "ZERO-MPG" or something like that. A friend warned me that going west on I-80 this summer will gobble gas with the prevailing winds, but maybe going east will make up for it some. Doubt it. I have to agree with AbdRahim.

 

[Calsun]

A great deal depends on how fast you drive on the highways as the air drag goes up with the square of the speed. At 80 mph the air drag is 4 times as great as at 40 mph and with any such vehicle I do testing to find the sweet spot. In the past I have found that I would get the highest mpg at 62 mph and my fuel consumption would increase at faster speeds. Wind speed is another factor and with a 15 mph head wind my RV at 60 mph had the fuel consumption of driving it at 75 mph without the wind. A cross wind has two-thirds the vector force of a headwind so a 10 mph crosswind is going to be like driving 6-7 mph faster with the vehicle.

The difference between 7 mpg and 9 mpg may not seem like much but at 7 mpg the fuel consumption is 22% higher and so you will be making a fuel stop that much sooner. On the plus side, the 450 based chassis cab RVs tend to come with 50 to 55 gallon gas tanks. The problem then becomes the $75 limit at many gas stations unless you go inside with the credit card and have a smart cashie (not a problem at truck stops).