open header

To have your car's engine run with the exhaust manifold bare, rendering it obnoxiously loud, according to rice boy standards. Your general stock cars are by itself equipped with these items, that guide, muffle, and clean exhaust gases, as well as reduce performance by increasing backpressure: Exhaust Manifold - A sturdy structure that covers the exit paths after your exhaust gases has left when the exhaust valve opens. It purpose is to collect exhaust gases so it can be either pumped with air to burn undercombusted hydrocarbons (provides no power, but better smog tests) via air injection, or further send down the tailpipe, where further methods are undertaken to quiet and clean the expanding exhaust gases. Tailpipe - Narrow metal tube, that not only directs the exhaust gases to the back of the car (or to the sides), but because of its small diameter, slows the flow of gases, quieting the motor significantly (an a explosion for example is basically a loud expansion of gases). Slant eyed rice enthusiasts would take the hint, and install gigantic fart cans to their tailpipes to turn their tranquil hum of their civics into a vomit-inducing whine. Like they even need it anyways. Muffler - As it's name states, it further "muffles" the sound of the still rapidly traveling exhaust gases by forcing it through a series of small intricate pipes. Catalytic Converters - Helps burn excess uncombusted hydrocarbons that have unfortunately had not be burned up after introducing air into the exhaust manifolds (temperature still hot enough to ignite raw fuel), via air injectors operated by a air pump. Also, it helps get rid of Oxides of Nitrogen (Unuseable, unlike Nitrous Oxide), and changes carbon monoxide into less lethal, carbon dioxide. Catalytic converters reduce performance and sound just as much as mufflers, though if overworked (if your car has rich-fuel problems), it would glow and strain, melting the honeycomb like structures inside, further clogging the path in which exhaust can escape. A obstructed path for exhaust gases to escape is very bad for engine performance, if nearly completed plugged, exhaust gases have nowhere to go but back into the combustion chamber, causing the motor to run terribly, or stall. The idea of running your car, preferably a hot rod open header, is to increase performance, lessen the strain on the engine, make it sound louder and more macho, as well as to impress your friends. Unless your attending a open header contest with other like gearheads, removing any of the above components is ILLEGAL as stated by the DMV. But at least this definition gives you something about exhaust and performance.