Rebuilt locomotive supercharger
Superchargers are a natural addition to aircraft engines for operation at high altitude. As an aircraft climbs to higher altitude, the pressure of the surrounding air quickly falls off. Superchargers are used to increase the power and torque output of an engine by forcing more air into the engine. This additional air carries more oxygen allowing more fuel to be burnt at a single cycle thus raising output. Superchargers are comparable in price to turbo kits in most cases. Either turbos or superchargers can make any amount of boost based on what kind of system you install.
Superchargers are probably the biggest power-adder you could ever get for your truck. Instead of your engine sucking in air to make power, a supercharger forces air into your engine. Superchargers are crank driven, by belts. They don't really exhibit "turbo lag". Superchargers are of the roots type design that provide consistent boost and compress the intake charge very efficiently with a minimal increase in air intake temperature. This combination helps provide almost instant boost (unlike centrifugal type superchargers) to increase and broaden the torque curve substantially.
Superchargers are relatively simple machines, however, finding maximum power and keeping the engine alive is a different thing entirely. This part of the equation is complicated indeed, but we plan to diffuse the important facts and expose the myths. Superchargers are substantially easier to install than a turbochargers because they have far fewer components and simpler devices. Turbochargers are complex and require manifold and exhaust modifications, intercoolers, extra oil lines, etc. Superchargers are generally the reason why tuned engines have a distinct high-pitched whine upon acceleration.
Boost is controlled by the size of the pulley, larger pulleys giving lower boost levels, and small pulleys giving higher boost levels. The 240sx can probably handle about 5 psi of boost without a lot of tuning. Boosting, or adding a supercharger to a stock naturally-aspirated engine, has made something of a comeback in recent years due largely to the increased quality of the alloys and machining used in modern engines. In the past, boosting would dramatically shorten an engine's life due to the extreme temperature and pressure created by the supercharger, but modern engines produced with modern materials provide considerable overdesign and boosting is no longer a serious reliability concern. Boost is the measurement of the increase in pressure in the intake charge over normal outside atmospheric levels. Typical boost levels for a street BMW range from 6 to 9 psi.
Boosting, or adding a supercharger to a stock naturally-aspirated engine, has made a comeback in recent years due largely to the increased quality of the alloys and machining used in modern engines. In the past, boosting would dramatically shorten engine life due to the extreme temperature and pressure created by the supercharger, but modern engines produced with modern materials provide considerable overdesign; thus, boosting is no longer a serious reliability concern.