What can result from using fuel of a lower octane rating than recommended for an engine?

Using fuel with a lower octane rating than recommended for an engine can lead to detonation, also known as engine knocking. Detonation occurs when the air-fuel mixture ignites prematurely in the engine's combustion chamber, rather than igniting in a controlled manner through the spark plug. This premature ignition can cause a rapid rise in pressure, leading to a knocking sound and potentially damaging the engine components over time.

Engines designed for higher octane fuel are calibrated to operate effectively under specific pressure and temperature conditions. When lower octane fuel is used, it can combust violently, leading to excessive stress on the engine parts, which may result in mechanical failure or reduced performance. This is why it is crucial to adhere to the manufacturer's fuel recommendations to ensure optimal operation and longevity of the engine.