Based on how a car engine works, with the principle of igniting a compressed air-fuel mixture to get power, car manufactures can adjust a number of variables to get more power from the engine or make the car more energy-efficient. One way of increasing power is to increase the amount of air and fuel being compressed by making more room in the cylinders. This can be done by manufacturing larger cylinders or by making cars that have more cylinders, with 12 cylinders as the maximum at this time.
The more the air-fuel combo is compressed, the more power you can get, but you're running a risk that the mixture could ignite spontaneously before the spark plug goes off. Racing cars with high-compression engines usually use higher-octane gas, which prevents combustion from happening too early. Related to this method is the idea of stuffing more air and fuel into the cylinders with turbochargers and superchargers. When air is compressed, though, its temperature rises, so when it's ignited, it expands less. Therefore, supercharged and turbocharged cars also come with an intercooler, which cools down the air before it goes into the cylinder.
Other ways to get more power out of your car’s engine are to make it easier for air to enter and leave the engine via the valves. Adding more intake and exhaust valves enables more air to get into and out of the engine, so when you hear a car manufacturer boasting that his cars have four cylinders and 16 valves, it means he has four valves per cylinder. In order to cut down on drag caused by exhaust having a hard time leaving the car, larger tail pipes or two tail pipes (dual exhaust) are sometimes used.