The best way to increase the power obtained from an engine is to increase the amount of fuel and air mixture sent to the cylinders.

This can be achieved in two ways:

1- Increasing the volume of engine,
2- Applying supercharge or turbocharge

Increasing Engine Volume

It is possible to increase air-fuel ration by increasing engine volume. But this means receiving more power by consuming more fuel (and more money spent on fuel). Also there are other negative aspects like increase size and weight of these engines and increased friction.

Supercharge

Supercharge is technique used in internal combustion engines to increase power generation. Normally the positive displacement of a piston causes the intake of air and this air is compressed and used in combustion. The more air you can send into the cylinder the higher power you receive. Supercharge technique is based on this principle. In this technique air is compressed by a compressor prior to sending to the cylinder and due to high pressure, more air can be pushed into the same volume of cylinder. Consequently more fuel is consumed and more power is generated from the same engine due to supercharge, without increasing engine volume.

Turbocharger

Turbocharger can be described as supercharging based on exhaust gas. Its power comes from the pressure of exhaust gas, unlike supercharge which uses belts and gears. Turbocharger is a kind of pump, which sends, to the engine, air above atmospheric pressure, i.e. forced filling, and allows generation of higher power from lower volume engine, and takes its motion from the exiting pressure of exhaust gas. It has two wheels, turbine and compressor. Turbine is located on the exhaust side, while compressor is on the inlet side. Turbine turns due to the exiting pressure of exhaust gas and in turn, rotates the compressor wheel with the help of connecting shaft. This way the air intake into the engine cylinder is increased considerably.