Originally Posted by Red-Stripe
Not surprised at all. MPG is achieved at 1,200-1,800 rpm's. At those RPM's the stock system is oversized and there is NO restriction with a clean filter. Then factor in when it drops to 4 cylinders at those Rpm's and you have less air flow than a squirrel fart.
Do you really have less air flow, part of the gains from switching from 8 to 4 is to lower pumping losses by opening the throttle up plate further. I do agree that the stock setup has more than enough flow for part throttle operation and more than likely WOT operation also. The RAM air box is pretty nice as is.