Engine tricks aren't the only modifications responsible for the magic number 26. You've probably noticed the custom faring constructed over the pickup bed. It's made from the rubber matting used for tread on stairs (with the ribbed side facing down) which is said to eliminate the drag created when air comes off the roof and drops down into turbulence created in the bed. An Excursion bumper was mounted up front because it has an extra-long spoiler that doesn't come on a Super Duty. This modification is very effective at keeping air from causing drag on the undercarriage because the truck has been lowered by 3 inches in the front and 4 inches in the rear.
The Future
Dave has already managed to improve the fuel economy to 26 mpg (up from the stock 20 mpg), so what's next? Lots of things. He's been eyeing a conveyer belt that would make a good front air dam extension, he'd like to remove the side mirrors and replace them with small video camera pods, and you may see land-speed record style solid-face wheels at the corners. Some more expensive modifications being considered include bobbing the bed and using a tonneau cover mounted at a 25-degree angle over the bed with custom side panels.Even without making any other modifications, Dave can drive happy knowing he's dramatically improved the fuel mileage by 30 percent over a stock Super Duty. A Chevy Malibu also gets 26 mpg on the highway, but wouldn't you rather drive a 1-ton?
 The efficiency of the 7.3L...  The efficiency of the 7.3L engine was maximized with a Baldwin PA2818 air filter, a 203-degree thermostat, a disabled backpressure valve, a custom fuel-saving computer chip, a second oil filter, Amsoil synthetic oil, waterless coolant, and an auxiliary coolant filter. A dealer-installed Ford idle controller gives the driver precise control of the engine speed. |  The sidestream coolant filter...  The sidestream coolant filter diverts about one-fifth of the water-pump flow to eliminate rust and other harmful deposits. Dave wanted to remove all water from the coolant system, so he drained it and then used a hair dryer to get rid of any leftovers. The standard 50/50 mix was replaced with Evans waterless coolant made from non-aqueous propylene glycol. |  Gauges to monitor the EGT,...  Gauges to monitor the EGT, boost pressure, and outside air temperature are mounted on the A-pillar for easy reference. The 3.08 axle gears that allow driving at super-low engine rpm also keeps the EGT at less than 600 degrees when Dave is cruising down the freeway. |