The real issue is how do they measure rpm.
You do not need to have the engine perform a complete revolution to 'log' a speed - it is sufficient to measure the time interval between spark ignitions. In fact this is the way many rev counters in the dash work. Therefore if you have the interval between two sparks shorter than x msec then you log a single incident of any given rpm.
You do not need to have the engine perform a complete revolution to 'log' a speed - it is sufficient to measure the time interval between spark ignitions. In fact this is the way many rev counters in the dash work. Therefore if you have the interval between two sparks shorter than x msec then you log a single incident of any given rpm.
