FREQUENTLY ASKED QUESTIONS
WHAT IS A TORQUE CONVERTER?
A device for changing the torque-speed ratio or mechanical advantage between an input shaft and an output shaft. A pair of gears is a mechanical torque converter. A hydraulic torque converter is an automatically and continuously variable torque converter, in contrast to a gear shift, whose torque ratio is changed in steps by an external control.
A mechanical torque converter transmits power with only incidental losses; thus, the power, which is the product of torque T and rotational speed N, at input I is substantially equal to the power at output O of a mechanical torque converter, or T1N1 = kT0N0, where k is the efficiency of the gear train. This equal-power characteristic is in contrast to that of a fluid coupling in which input and output torques are equal during steady-state operations..
In a hydraulic torque converter, efficiency depends intimately on the angles at which the fluid enters and leaves the blades of the several parts. Because these angles change appreciably over the operating range, k varies, being by definition zero when the output is stalled, although output torque at stall may be three times engine torque for a single-stage converter and five times engine torque for a three-stage converter. Depending on its input absorption characteristics, the hydraulic torque converter tends to pull down the engine speed toward the speed at which the engine develops maximum torque when the load pulls down the converter output speed toward stall. From, McGraw-Hill Encyclopedia of Science and Technology, 5th edition, published by The McGraw-Hill Companies, Inc.
- It transfers engine torque to the transmission allowing the vehicle to come to a complete stop without stalling.
- It multiplies the engine torque to the transmission resulting in greater vehicle performance.
- It provides a direct-drive, or mechanical link from the engine to the transmission, which is accomplished by using a torque-converter clutch.
WHAT IS A LOCKUP TORQUE CONVERTER?
Pumping losses within the torque converter reduce efficiency and generate waste heat. In modern automotive applications, this problem is commonly avoided by use of a lock-up clutch that physically links the pump and turbine, effectively changing the converter into a purely mechanical coupling. The result is no slippage, and virtually no power loss.
The first automotive application of the lock-up principle was Packard's Ultramatic transmission, introduced in 1949, which locked up the converter at cruising speeds, unlocking when the throttle was floored for quick acceleration or as the vehicle slowed down. This feature was also present in some Borg-Warner transmissions produced during the 1950s. It fell out of favor in subsequent years due to its extra complexity and cost. In the late 1970s lock-up clutches started to reappear in response to demands for improved fuel economy, and are now nearly universal in automotive applications. From Wikipedia, the free encyclopedia
WHAT IS A PERFORMANCE CONVERTER?
A performance torque converter is designed to match the performance characteristics of your vehicle or to accomplish a specific level of desired performance. They are manufactured differently than regular stock torque converters:
- Components are strengthened to accommodate the additional power.
- Internal characteristics of the torque converter are altered in order to transfer the additional power.
- Stall speed is adjusted to more closely match the power curve of your specific performance requirements.
HOW DO I DETERMINE THE BEST CONVERTER FOR MY VEHICLE?
There is no general answer to this question unless the application is for stock use. The answer is simple then; a stock converter for a stock application. Because each performance converter is built for your specific needs it is best to supply the online data relative to your needs or call us toll free and speak to one of our experts to determine your perfect torque converter.
HOW DOES THE TORQUE CONVERTER AFFECT THE PERFORMANCE OF YOUR ENGINE PACKAGE?
Whatever level of power you have created with your engine, it is the job of the torque converter transfer that power. You will waste that power if you are use an inferior OE torque converters with your performance package. A performance torque converter is designed to work in concert with the engine will maximize its power to the wheels.
HOW DOES THE RIGHT TORQUE CONVERTER PROLONG THE LIFE OF THE TRANSMISSION?
The right torque converter reduces slippage thus producing less heat for longer transmission life. The proper cooling system is also essential to prolonging the life of the transmission.
HOW DOES THE TORQUE CONVERTER WORK?
The torque converter is a fluid pump that shares fluid with the transmission. That fluid is pumped outward toward the outside of the torque converter. An impeller, which is similar to a small fan, is inside is the torque converter. It uses centrifugal force to pump the transmission fluid. The impeller faces the turbine of the engine. The faster the turbine spins, the faster the impeller spins and, subsequently, more torque is transferred from the engine to the transmission.
WHAT IS THE STATOR?
The stator assembly is in the very center of the torque converter and redirects the flow of fluid returning from the center of the turbine in the same direction that the engine is turning the converter pump.
WHY DO DIESEL POWERED VEHICLE REQUIRE LOWER STALL SPEEDS THAT GASOLINE POWERED VEHICLES?
Performance gasoline engines produce power at a higher rpm and need a higher stall speed torque converters to put more power to the wheels quicker. Performance diesel engines produce power at a lower rpm and need a lower stall speed torque converter to put more power to the wheels quicker. Typically, when achieving maximum acceleration, stall speeds will match the peak torque rpm of the engine. By lowering the factory stall speed from 2,000-2,500rpm level to the 1,600-1,900rpm range, where most diesel engines produce maximum torque, significant gains can be made in acceleration, throttle response, fuel efficiency and towing.
WHAT DO YOU WANT FROM YOUR TORQUE CONVERTER?
We will customize your torque converter, whenever possible, relative to your desires. Please take the time to supply us with your vehicle specific information and our experts will provide you with the right converter.
WHY SHOULD YOU ORDER YOUR TORQUE CONVERTER FROM TORQUE CONVERTER TECHNOLOGY?
The answer is simple. With over 90 years of experience in the torque converter and transmission industry and our famous Limited Lifetime Warranty we can provide you with the customized service your individual desires require.
WHAT IS THE MYSTERY OF STALL?
The most confusing issue between the High Performance torque converter builder and the customer is the word STALL. Torque converter stall speed is the RPM a given torque converter combination allows the engine to attain with a given engine torque input.
Brake Stall is attained when the transmission is put in gear and the brakes are held with the brake pedal and the accelerator is slowly pushed to the floor. The RPM the engine reaches the moment the rear wheels of the vehicle start to spin is known as Brake Stall. Because the rear brakes cannot handle the torque multiplication of the torque converter this stall speed figure will be very low, approximately 800 - 1000 RPM under True Stall.
Flash Stall is attained when the vehicle is driven at a very slow speed then accelerated hard by depressing, the throttle to the floor while looking at the tachometer and noting what RPM the engine has reached. If the wheels spin the reading will not be accurate, thus making this method not as accurate as others. Installing a manual valve body in the transmission makes this method very accurate by allowing you to shift the transmission in to high gear and then accelerate from a standing start with very little chance of tire spin.
True Stall is the most accurate of the stall readings and the method you will want to use. True Stall is the holding RPM of the torque converter with the engine at wide open throttle and the transmission locked so the driveshaft cannot rotate. Remember that Stall speed varies depending how much torque is applied to a given combination in the torque converter. For example if you had a torque converter behind an engine that developed 400 HP and True Stall tested it and the engine RPM reached 4500 RPM you would identify this as a 4500 RPM stall converter. Likewise, if we took the same converter and put it behind an engine that developed 800 HP and we then True Stall tested it and the engine RPM reached 6000 RPM we would call this a 6000 RPM stall converter.
Many variables will determine the correct Stall Speed for your desires. Please provide us with your specific vehicle information and one of our experts will determine the perfect torque converter for you.