S (stall point): Within this place the turbine speed is zero and the impeller is rotating; the effectiveness during the stall position is minimum, all over 50%, which implies that 50 % of the power coming in the engine is missing through friction and dissipated as warmth; at this stage https://torqueconverterclutch29627.isblog.net/the-definitive-guide-to-torque-converter-clutch-51401230