Guys, thinking about buying a 2008 4x4 F-150 or 4x 4 Explorer with a 4.6 3V...want to know if anyone has changed the rear gear to a 2.73 or less to improve gas mileage on the highway. Also will any old school tricks like headers, K&N Filter, and free flow exhaust help....looking for ideas on how to get the best gas mileage possible...I will not be towing with this vehicle for awhile...Thank you.

 

gear change is a waste of your time to go backwards...not to mention you'll actually end up burning alot more gas since the motor will be out of it's power band to offset the higher gears.


the other stuff will help, but really a Tuner is what will really help out in the performance area.

 

3.31:1 is the highest rear they make for the F-150. You could probably make an aftermarket gear set work at great cost/trouble.

 

You say you will not be towing for a while... leave it stock. Tuner will help with shift and performance issues but not without a cost. Why 4.6 vs 5.4? Not much difference in milage but power is quite different.

 

Can you explain what is meant by a "Tuner"?

 

The factory programming is usually set to meet what the vehicle manufacturer deems is the best balance between longevity of the motor, meeting emissions standards, and providing power. A tuner is any number of purpose-built computers that can interface with a vehicle's computer to modify/overwrite that factory programming and/or the electrical signals going into or out of the vehicle's computer.

While the primary aim for most tuners is increased performance, they do offer several other niceties. Some tuners--like the ever popular Edge (http://www.edgeproducts.com/)--have digital displays to simulate additional gauges. Some offer the ability to change the tire size (for correcting speedometer display after changing tire sizes), shift points, shift firmness, speed & rev limiters, and other things.