What is Torque Converter Stall?

Stall speed is the point where a converter has reached it’s maximum fluid flow or it has hydraulically locked up because torque multiplication has reached it’s highest point.

All stall speed ratios are approximate and will vary, based on the torque of the engine. Small and Big Block combinations will vary 300 to 500 R.P.M.’s Stall speed is the amount of engine R.P.M. that can be attained at full throttle with the brakes locked and the transmission in gear before the drive wheels turn. It is very important to determine that if your vehicle drive wheels turn before the desired stall is reached, you must either “flash” the converter to attain higher stall or install a brake proportioning valve that directs more fluid to the drive wheel brakes to better hold the vehicle. In either case, attainable stall ratio will not exceed 3500 R.P.M., due to the vehicle braking system, which is even worse with disc brake equipped cars.

Performance engines are modified to produce more horsepower and torque and it is essential to know what the peak torque or your engine is and to match the stall speed ratio of the torque converter with the engines power curve. This match will give the optimum performance or “launch” of the vehicle. There are no closer-tied components in any vehicle than the engines’ camshaft and the torque converter. Attention to this detail is of utmost importance to your vehicle’s optimum performance.