Normally aspirated...... is totally unassisted and uses manifold vacuum to induct air into the engine. Turbo-charged...... use an exhaust driven turbine to force air under pressure into the intake. The turbo is mounted into the exhaust engine pipe and has a waste gate valve to control the amount of boost. As the air is forced into the cylinder above atmospheric pressure the air is denser giving more available oxygen. This increases the power output of the engine. Super-charged...... uses a belt or gear driven air pump to force air under pressure into the intake. The power advantages due to forcing air into the cylinders from a belt driven pump are much better at low revs than a turbo. This system is more positive than turbo charging and does not suffer the lag problems associated with turbo charging.