A torque converter has three stages of operation: stall, acceleration, and coupling. Stall is when the transmission is in gear, but the brakes prevent the car from moving. At stall, the torque converter can produce maximum torque multiplication, called stall ratio, if sufficient input power is applied.

A stall converter is a bit more gentle on those parts because of the “slip” it has. Stall converters allow the car to launch in it’s torque curve and get off the line much harder than a car that has much less stall.