How does a turbocharger improve engine performance?

A turbocharger enhances engine performance primarily by forcing more air into the combustion chamber. This process increases the volume of air available for the combustion of fuel, leading to a more efficient and powerful explosion within the cylinders. When more air is compressed into the combustion chamber, it allows for a higher fuel-to-air mixture, optimizing the combustion process and contributing to increased power output. This results in improved acceleration and overall engine performance, especially at high altitudes where air density is lower.

The other options, while relevant to engine performance in different contexts, do not accurately capture the primary function of a turbocharger. For example, while fuel efficiency is important and can be influenced by turbocharged engines, the main role of the turbocharger is to enhance air intake rather than specifically improve fuel efficiency at low RPM. Moreover, turbochargers typically add weight and complexity to the engine rather than reducing it, and they do not simplify the exhaust system design—in fact, they often require more sophisticated exhaust routing to function effectively.