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TURBOCHARGERS

Turbochargers use the same type of compressors as the above and are centrifugal. The method for driving a turbo is with a turbine wheel in the exhaust tract. The heat energy and velocity of the engine's exhaust are used to accelerate the exhaust turbine that is connected to the compressor section.

In theory the turbo is the most efficient means of supercharging as the exhaust is already spent energy and therefore it is free energy being used for valuable intake compression. The downside to a turbocharger is the time required for the turbine to reach the optimum compressor rpm and also the heating of the intake charge from the turbine temperatures.

INTERCOOLERS

All of the methods of mechanical supercharging have the same goal: to increase the quantity of intake air charge resulting in increased horsepower output. All of the superchargers suffer from the same problem: heat. It is basic physics that anything which is compressed has an increase in temperature due to the act of compression. This is why the intercooler is a valuable tool in controlling the discharge temperature.

The intercooler is simply a heat sink device that absorbs heat energy from the compressed intake charge and makes the compressed air charge cooler and more dense and workable.

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An intercooler can either be of the air-to-air or air-to-water design. Air-to-air simply means that the medium the heat energy is moved away from the intercooler is simply moving air. The popular drag racing intercooler is air-to-water. A super-cooled liquid can be pumped through the intercooler, thus dropping the discharge temperature dramatically.

The centrifugal and turbocharged designs require the use of intercoolers to make the power required that is required to compete in doorslammer racing, partly due to the use of gasoline. The roots and the screw design will also benefit dramatically from the use of an intercooler, as you see in many marine applications using this type of supercharging.

COMING IN PART 2: Advantages and disadvantages