What is valve lag on a engine?

Valve lag in an engine refers to the delay in the opening and closing of the engine's intake and exhaust valves relative to the position of the piston. This lag can affect engine performance, efficiency, and emissions, as it can lead to suboptimal air-fuel mixture intake and exhaust gas expulsion. In high-performance engines, managing valve timing through advanced technologies like variable valve timing (VVT) helps reduce valve lag, optimizing power delivery across different RPM ranges. Proper tuning of valve timing is crucial for achieving peak engine performance.