Originally Posted by
Erwin8r
Well, I do think there are things we can do to make our engines/drive trains more efficient, and thus increasing MPG. For example, removing or by-passing the EGR will not allow spent gases to be re-introduced into the combustion cycle. This will improve efficiency. Using the right tires for your gearing, inflated to the proper PSI will improve efficiency. IMproving intake (zoodad, etc.) , removing the cat and adding an un-restricted exhaust system improves efficiency. Optimal tuning, although primarily a power ennacer, can also improve efficency. All these things can add up.
Sorry, but as 69cj states I don't agree either. Especially the zoodad mod. Unless you are pushing way more power, the stock intake is good. You are just exposing the intake to more road debris and moisture (rain/snow). I've seen the filters on those and when the first two inches are wet as a dish rag, I can't see that helping. Mine is dead stock and in the winter I get 17 mpg on the highway, summer it's around 20. Yes, that's measured. Usually drive at 68 mph (110km/hr) with cruise set. After that it tanks. The exhaust I can see making a little difference, however you would have to see a far more massive increase in efficiency to justify the cost.
Diesel World - More MPG for Your Super Duty have a read through this article and you can draw your own conclusions.