Turbochargers And Superchargers
Let's start with turbos. A turbocharger, according to the Society of Automotive Engineers (SAE), is "a device for increasing the pressure and density of the fluid entering an internal-combustion engine using a compressor driven by a turbine that extracts energy from the exhaust gas." Well, that certainly clears things right up.Turbochargers (and superchargers) are air pumps. They increase a piston engine's power by forcing more air (and, thus, oxygen) into its cylinders than can atmospheric pressure alone. More oxygen (and the associated effective increase in compression ratio) means more fuel can be burned, creating more power!.Turbochargers employ otherwise wasted engine-exhaust gases to spin a fan inside a snaillike turbocharger housing. A shaft connects this fan, sometimes called the turbine wheel, to a compressor fan in the other, and separate, half of the housing. Turbos' advantages over superchargers include lighter weight smaller size (for easier underhood packaging), and better fuel mileage during easy driving. Turbos' disadvantages include a delay of power delivery between when the driver stands on the gas and when increasing exhaust gas flow causes the turbo to spool up enough to pump a useful amount of air, a.k.a. "boost."/ A supercharger is described as a mechanically driven-usually via a belt from the crankshaft-compressor. Most commonly, the compressor is composed of a pair of gearlike devices, turning in opposite directions, inside a housing that you never want to take apart for any reason.A leading advantage of supercharging is instant power availability at low engine speeds. Compared with turbos, superchargers' disadvantages include higher weight and, since they're pumping air even when you don't need extra power, reduced fuel economy and increased engine wear. The "intercoolers" found on many forced-induction cars are radiatorlike heat exchangers to remove some of the heat that compression puts in the intake air. Hot intake air isn't conducive to maximum engine performance. Air-to-air intercoolers work just like conventional radiators, except that intake air, not engine coolant, flows inside the intercooler. Air-to-water intercoolers are surrounded by a jacket through which engine coolant is pumped.
