S (stall level): in this issue the turbine velocity is zero and also the impeller is rotating; the performance from the stall stage is minimum, all around 50%, which implies that half of the power coming from your motor is missing by friction and dissipated as heat; at this stage https://johnathanpuutq.aboutyoublog.com/38263253/helping-the-others-realize-the-advantages-of-torque-converter-clutch