SuperCharging and TurboCharging

Supercharging and Turbocharging By DAVID BOOTH AutoVision Supercharger. For anyone even slightly enamored of motorsports the word conjures up images of Top Fuel dragsters, Racing slicks and horsepower figures that seem more in keeping with F1's than anything remotely construed as an automobile. Supercharging is actually a generic term applied to any device that increases an engine's power output by force-feeding it high-pressure air. The supercharger on top of John Force's dragster is a form of supercharging, but then so is the turbocharger that's hidden deep within the bowels of a lowly Chrysler LeBaron. Confused? A bit of basic information on how supercharging works will bring clarity. • The engine in your car works remarkably like your body's breathing apparatus. When your brain determines it's time to breathe, it tells your diaphragm to expand. This, in turn, expands your lungs creating a vacuum allowing air to rush in through your nostrils (unless you're Mike Modano at the end of a long shift in game six of the NHL playoffs, in which case you'll want to suck it through your mouth, and even your ears if you could Just get the darn things to open). The analogy works if you think of your nostrils as the engine's intake valve, your lungs as the cylinder and your diaphragm's the pistons. As the piston moves downward, it creates a vacuum. The intake valve opens and presto, air rushes into the cylinder (it's later mixed with gas, compressed and ignited creating the combustion that propels your car). The amount of air that can be sucked into an engine is limited to the difference between the pressure in the atmosphere (in most cases, around 14.7 psi (pounds per square inch of air pressure) and the vacuum inside the cylinder (for sake of discussion, 0 psi). That means that the force trying to ram air into your engine is equivalent to a pressure difference of 14.7 psi, at best. It didn't take long for some bright light to figure out that ramming more air into an engine would result in more horsepower. READ MORE