What does ignition advance imply?

Ignition advance refers to the timing of the spark that ignites the air-fuel mixture in an engine's combustion chamber. When we say ignition advance occurs, it means that the spark plug fires sooner in the engine's power stroke than it would at the base timing, which is the predetermined point of firing. This earlier ignition allows for more complete combustion, improving engine efficiency and performance by maximizing the power generated from the combustion process.

It is essential to understand that firing sooner than the base timing is often critical for achieving optimal engine performance, especially at higher RPMs or under load. This approach helps ensure that the maximum pressure from the expanding gases occurs at the right moment in the power stroke, ultimately increasing torque and horsepower.

Other choices do not reflect the technical understanding of how ignition timing works. Firing late would typically lead to decreased performance and potential engine knocking, firing at the base timing means the spark is delivered exactly as designed without any advance, and not firing at all means there would be no combustion, which would prevent the engine from operating. Therefore, the correct understanding of ignition advance is crucial for tuning and maintaining engine performance effectively.