There has been no change in gas mileage - no difference between the factory setup, the AIRAID as-is, or my modified AIRAID. I got between 15.2 and 15.5 in town with the factory intake, and get the same with the AIRAID. Any aftermarket CAI source that attempts to sell you a CAI by making fuel economy claims is lying to get your money out of your wallet. At normal throttle openings the factory intake represents no impediment to fuel economy. With the EPA breathing down their necks, you don't think that Ford would make a stupid mistake like that, do you?
If you do a little measuring, you will discover that the inside diameter of the factory intake snorkle is larger than the inside diameter of the main intake tube at the airflow sensor. That means that the snorkle will flow more air than the tube! The reason I added the extra intake hose was to insure that a minimum of air drawn into the filter is hot air from inside the engine compartment, not because I thought that the engine might not get enough intake air. That would be impossible given the dimensions of the intake tube and the intake snorkle, and the open top of the AIRAID CAI. You might also note that I tried a larger tube and found that it would not physically fit.
So why do it? Why spend the money? Answer: Throttle response and top end performance. All of the F-150s breathe through the same intake components (with one or two minor changes for the EB engine). This is fine and dandy for normal throttle openings when the big 6.2L isn't trying to gulp air from three states. But when you floor it to pass another vehicle on the Interstate or to blow through a sand wash, I am convinced that peak performance suffers because our big, high performance V-8s are trying to breathe through the same components as the 3.7L V6. With the factory intake my Raptor had a pronounced hesitation to abrupt throttle changes. With the AIRAID CAI that problem is gone.
