Ford Expedition Intake and exhaust
I've got an '03 Ford Expedition XLT 4X4 with the 5.4 (3.73 differentials). I've been considering the addition of an open element air filter and intake and some type of cat-back exhaust to open it up and make it breath a little better. Anybody have any experience with these mods, and if so, what kind of power and milege improvements have you noticed. I'm currently running a K&N filter in the stock air box, and Mobile One synthetic in the crankcase. I am hitting almost 17 on the highway. I'd consider everything successful if I increased to 18 or better on the highway. I've thought about trying to have a true dual exhaust with a crossover fabricated, but I don't know if there is enough clearance with the independent rear suspension unless I go with side exits.