How does excessive back pressure affect engine performance?

Excessive back pressure in an engine primarily inhibits exhaust gas flow. This occurs when the exhaust system is challenged by restrictions, such as constricted piping or malfunctioning components like catalytic converters or mufflers. When back pressure builds up, it makes it harder for the engine to expel exhaust gases, which can lead to a reduction in the engine's overall performance.

With increased back pressure, the engine may struggle to complete its exhaust cycle effectively, leading to an increase in residual gases left in the combustion chamber. This not only reduces the engine's ability to take in fresh air-fuel mixture but can also contribute to higher operating temperatures and decreased efficiency. The overall result is diminished power output, poor fuel efficiency, and potentially even engine damage over time if the issue persists.

In summary, by significantly obstructing the free flow of exhaust gases, excessive back pressure negatively affects the engine's performance, making inhibition of exhaust gas flow the critical aspect that highlights its detrimental impact.