What could result if manifold pressure exceeds rated boost in a turbocharged engine?

When manifold pressure exceeds the rated boost in a turbocharged engine, detonation and engine damage could result. In turbocharged engines, the boost pressure directly affects the air-fuel mixture within the engine's cylinders. If the manifold pressure surpasses the engine’s design limits, the mixture can become overly rich in fuel, leading to uncontrolled combustion. This uncontrolled combustion is known as detonation, which occurs when the air-fuel mixture ignites prematurely, creating excessive pressures and temperatures within the cylinders.

The consequences of detonation can be severe, leading to engine knocking, premature wear, and potential catastrophic failure, including damage to pistons, valves, and the overall engine structure. Therefore, it is crucial for pilots and engineers to monitor manifold pressure closely and ensure it stays within safe operational limits to maintain engine integrity and performance.