I've been reading the posts in this forum, looking for some ideas to improve the gas mileage from my 2008 E350 Super Duty 12 pax van. It has the 5.4 2V engine, the 4R75E trans, and the 3.73 standard rear axle. I don't see much discussion about how someone has improved on the 10 to 12 mpg I seem to be getting. My own ciber research came up with a K&N Cold Air Kit (a possible 5mpg gain) and a computer chip (maybe another 5mpg gain). Am I asking to much? Is there an engine swap in my future? Anybody looking for a test project? Answer when you can.

 

you might try this and see if your mileage increases put higher gear ratio in the pumpkin you want to stay away from doing a motor swap if you can because if you put in a smaller engine then you may have to change the computer as well. you can also try having the tires changed for some taller ones even though the difference between the 235-75-16 and the 265-75-16 isn't a real gain in hight

 

There is a technology that I thought had died because I only saw it briefly in a JC Whitney catalog way back in the early 1970s. It's "water injection."

"In a piston engine, the initial injection of water cools the fuel-air mixture significantly which increases its density and hence the amount of mixture that enters the cylinder. The water (if in small liquid droplets) may absorb heat (and lower the pressure) as the charge is compressed, thus reducing compression work. An additional effect comes later during combustion when the water absorbs large amounts of heat as it vaporizes, reducing peak temperature and resultant NOx formation, and reducing the amount of heat energy absorbed into the cylinder walls." -Wikipedia

Sounds odd but there are sites and companies.
AquaTune.com
Aquamist (UK)
Devil's Own Water Injection
Water Injection