OMG, we're getting deep into the realm of physics here and it's painfully apparent that some people have absolutely no idea what they're talking about. Excon, did you ever take a high school physics course, or were you blazing up in bathroom or sleeping through it? First off, there are no "air molecules", there are nitrogen and oxygen molecules and molecules of other rarer gases that are at or near the low % level, which all make up air. Small point but I feel like being a smartass. Second, typically there is no negative pressure in a cars fender well at speed, ever see a late 60's Dodge Daytona or Plymouth Super Bee? Ever see those funny little scoops that point backward mounted on the top of the fenders and right above the front wheels? There are large holes in the fender tops right under those scoops that are there specifically to vent high pressure air that builds up under the front fenders at high speed and which contributes to front end lift. They needed some way to cover those holes so they put in those little scoops. I believe the Corvette C5R's also have grills or ducts on the fender tops for the same purpose, as well as the GTSR Vipers. Also, if there were negative pressure in the fender well that would not be an ideal place to put a CAI as that negative pressure would then be detrimental to the motor, since the number of available oxygen molecules would be that much lower. Remember, lower external pressure equals less efficiency and less horsepower, which is why a normally aspirated car in Denver makes less power than the same car at sea level, and why cars with forced induction don't suffer from changes in altitude, for the most part. Last, the ram air scoop in fact will create a higher level of air pressure available to the motors intake when moving at speed, in theory. There are two ways to increasing the air pressure inside a closed vessel, one is to pump more air in through mechanical assistance, namely using a compressor such as a turbo or supercharger. The other would be to create a flow of air into the vessels opening by moving it through that medium at high speed. Granted, the effect is small when dealing with cars, the area of the opening in the scoops face and the speed of travel being the limiting factors among other things, but the effect is proven. What makes the effect small on cars has as much to do with the scoops placement as speed or volume. Most auto scoops, ram air or not, are low in height, and operate in whats called the boundry layer of airflow over the cars surface. Ever see those pictures of a car in a wind tunnel with the white smoke flowing over it? Ever notice how that smoke stream seems to sit an inch or so off the surface of the car? Thats because as the moving air approaches the surface of the car, it gets slowed down by contact with it and friction, to the point of being almost still right at the surface. This is a well known effect in aerodynamics, and can have significant meaning to designers when considering where to put an aircrafts engine intake. This is one of the reasons why ram air is not that effective on cars, not that the physical theory is unsound. The theory is well proven, any high school kid can learn about it and understand it, but in order for it to be fully effective the scoop would need to be about a foot high so that it can get at the high speed non-turbulent air that exists above the cars surface and the car would need to be going at triple digit speeds, and the opening in the scoops face would need to be as large as possible. Anyway, my point is not that ram air does or doesn't work in a car. Given the typical scoops size, the cars speed, and the geometry of a typical engines intake, the effect is very small to none. My point was more to address the fact that Excon keeps blabbing that ram air is a myth and a physical impossiblity, when in fact it is a well characterized phenomenon. Pick up a physics textbook sometime dude, makes for interesting reading. If the ram air effect was a physical impossibility then all the billions of dollars that NASA has invested into the research of SCRAM jet powered aircraft would have been pissed away, but I distinctly remember the X-43 hitting over mach 9 back last November.
Oh, and aircraft wings don't create lift by generating high pressure. The upper surface of a wing is curved, while the lower surface of a wing is straight. As air flows over the wing two "packets" of air, one above and below the wing, must meet at the other side at the same time. Since the upper surface is curved, it is longer than the lower, and thus the air must travel faster to meet up with it's counterpart at the other side at the same time. This higher velocity air above the wing creates a negative pressure, which is whats called lift, or the Bernoulli effect. It's actually a bit more complex than that, but thats the common explaination.
