Performance Torque Converters of Texas

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Performance Torque Converters

The torque converter is an important part of the equation when it comes to producing the power needed to get your car moving. This part is a fluid coupling device that is attached between the engine and transmission that acts as a torque multiplier during initial acceleration. Multiplication occurs during acceleration and stall move when a torque converter produces more torque to drive wheels that the engine itself is producing. If you raise the horsepower of an engine but your converter is not built for the increase in horsepower, there will be little effect on your car no matter what performance car parts you have installed.

What Is a Torque Converter?

A torque converter is a fluid coupling device which transfers power from the engine to the transmission by pulling transmission fluid into the converter and pushing outward with centrifugal force. If your vehicle has an automatic transmission, you have a torque converter. It consists of three main internal components, which are the turbine, the stator, and the impeller pump. Each of these components has fins which direct the flow of fluid through the converter.

Torque Converter Components

The cover attaches to the engine flexplate and should remain rigid under torsional and thrust stress, and from the internal hydraulic pressure generated by the converter. The turbine attaches to the drive train via a spline fit to the input shaft of the transmission. Your stator changes the fluid flow between the turbine and the pump. It is what makes the torque converter a multiplier and not strictly a fluid coupler. In order for the stator to function properly, the sprag must work as designed.

Inside Of A Torque Converter
Hanging Car Parts

The sprag is a one-way, mechanical clutch inside the stator. It locks the stator in place while the converter is in stall mode. It also allows the stator to spin with the rest of the converter after the turbine speed nears the pump speed. This makes for a more efficient and less restrictive fluid flow.

An impeller pump is a centrifugal pump which attaches to the transmission side. It has a series of fins which drive the fluid into the turbine. The size of the torque converter and pump and the number and shape of the fins all affect the characteristics of the converter. It is important that the fins of the impeller pump are adequately reinforced against fatigue and the outside housing does not distort under stress.

Fin brazing (furnace or spot brazing) enhances the strength of the fins. The housing and fins should act as one unit. By reducing the amount of flex, fins are less likely to break under pressure. The more rigid the fins stay while they are under pressure, the more consistent the behavior of the torque converter. Needle bearings are important because they help the torque converter withstand more pressure and provide less drag inside the converter.

Race Car On A Track

Stall Speed

Stall speed is the amount of engine rpm that can be attained at full throttle with a transbrake engaged and the transmission in low gear before the drive wheels turn. Torque multiplication rapidly decreases until it reaches a ratio of approximately 1:1, which is no torque increase over crankshaft torque. A typical torque converter has a torque multiplication ratio in a range of 1.8 to 2.5:1.

The amount of stall needed to overcome the load depends on how much the torque converter needs to spin to generate enough fluid force on the turbine to overcome the resting inertia of the vehicle in wide open throttle. Load originates from two places - the amount of torque from the engine through the crankshaft, and from inertia, or the resistance of the vehicle to acceleration, which places a load on the torque converter through the drive train.


Let us help you learn the process of building torque converters from start to finish. This will cover:

  • Cutting the Weld
  • Cleaning the Components
  • Custom Fit Machining
  • Inspection & Replacement Of Worn or Damaged Parts
  • Custom Building
  • Pressure Testing
  • Precision Balancing
Parked Red Classic Car