What is the difference between a turbocharger and a supercharger on a cars engine?

Let's start with the similarities. Both <a href="http://auto.howstuffworks.com/turbo.htm">turbochargers</a> and superchargers are called forced induction systems. They compress the air flowing into the engine (see <a href="http://auto.howstuffworks.com/engine.htm">How Car Engines Work</a> for a description of airflow in a normal engine). The advantage of compressing the air is that it lets the engine stuff more air into a cylinder. More air means that more fuel can be stuffed in, too, so you get more power from each explosion in each cylinder. A turbo/supercharged engine produces more power overall than the same engine without the charging. The key difference between a turbocharger and a supercharger is its power supply. Something has to supply the power to run the air compressor. In a supercharger, there is a belt that connects directly to the engine. It gets its power the same way that the water pump or alternator does. A turbocharger, on the other hand, gets its power from the ...  more