John E. is right on the money. During a Fluid Dynamics class at NMSU, myself and a few friends looked into the benefits of what people refer to as "ram air" induction. We wanted to de-bunk the myths and see the numbers for ourselves more than anything. All you are doing is ducting high-pressure *cool* air from one of two optimum points - the front grille area of the car, or the base of the windshield. (we had a nice map of pressure points quantified by vectors along the profile of a sedan-type car..) Ducting this high pressure air into the intake has a pseudo-supercharging effect, which exists, but only at high speeds (100 mph+) (You have to overcome the demands of the motor before you can actually pressurize the intake.) The real benefit is the inductance of the cooler outside air as opposed to the hot underhood air. Colder air is denser air, rich in oxygen - which is what helps makes more power (when you have the right amount of fuel) The cold air has a bigger influence because we don't drive 100+ mph where ever we go.. (well, some of us at least..) So, yeah - the cowl induction has a function (did that rhyme??) but I think it exists to strike fear into the guy who lines up next to you.. Any little bit helps, and when GM uses what seems to be a gimmick (ram air Camaros?? should be *cold air* Camaros) most of the time they are preying on the hot-rod-engineer in all of us..
Here's a tidbit: Those drag cars with the huge hood scoop? They get an extra 150-200 hp from that huge scoop (thanks to the ram-effect), BUT it takes 80-95 hp to push that thing through the air.. Anyone wanna guess as to where they want to relocate that thing to get back that 80-95 hp??
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Linc Belt
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