ProTorque | Torque Converter Frequently Asked Questions - FAQ's
Unsure about the performance or racing torque converter you need? ProTorque provides you with an extensive frequently asked questions directory (FAQ's) to answer all of your torque converter questions. A great source for torque converter basics and help in choosing ProTorque.
Let's start with some basic QUESTIONS & ANSWERS ...
What is the difference between ProTorque and their competitors?
Many of our competitor's torque converters were designed with only the torque converter in mind. ProTorque converters are designed with the whole vehicle combination in mind, allowing for better torque multiplication rates and are more efficiency.
This allows for more power to be transferred and a better overall product.
What is the ProTorque difference?
ProTorque converters will have many differences from the units produced by the factory and other aftermarket rebuilders.
Beyond using top quality parts, and parts designed by our own R & D department, we custom build your converter to work with your entire vehicle combination; this results in better durability, performance and efficiency overall.
What is a performance converter?
A regular torque converter is designed for stock engines. A performance torque converter is designed to allow a vehicle to perform beyond the vehicles stock settings.
a) The torque converter is strengthened to handle additional power. b) The characteristics of the torque converter are altered in order to transfer additional power. c) The stall is adjusted to more closely match the power curve of a higher performance engine.
Why is a torque converter an important performance upgrade when installing a turbo system?
Theoretically, for maximum acceleration, the stall speed of the torque converter should match the peak torque rpm of the engine. If a high performance engine makes power at a higher rpm, then a higher stall speed torque converter can put more power to the ground quicker. When the same vehicle has a turbo installed you want to make sure that you are transferring power to the ground at the best possible rpm and best boost levels. If the stall speed of the torque converter is too low there can be some associated "turbo lag", or delay, until the engine rpm comes up and the turbo starts to build boost. The aftermarket performance converter that is properly matched to the turbo system will allow for maximum acceleration. In many cases a performance torque converter will take .4 - .6th's off of your quarter mile ET with no loss of drivability.
What is stall speed and how do I determine what stall I have now?
Stall speed is a term used to describe the rpm at which the torque converter transfers the power from the engine to the transmission. There are different ways to test stall speed. "Foot brake stall" is when you press the brake pedal and then press the gas pedal. When the engine rpm doesn't go any higher or the tires start to spin that is "brake stall". (DO NOT TRY THIS! THIS MEASUREMENT IS MEANINGLESS AND POTENTIALLY DANGEROUS TO YOU, THE TRANSMISSION AND THE TORQUE CONVERTER!) "Flash stall" is when you, from a dead stop, press the gas pedal to wide open throttle (wot). Watch your tach needle, you will see the needle jump to a certain rpm, that is "flash stall". A drag racing-style trans brake will give you closer to the true stall speed of a torque converter.
How do I determine the best converter for my vehicle?
This can sometimes be a difficult question to give a general answer to. In many cases performance and drivability are somewhat of a trade off. However with a properly matched torque converter and turbo system you can easily achieve the best of both worlds.
Because stall speed is dependent on input torque, in a light throttle situation the turbos don't build a tremendous amount of boost. Therefore the stall speed is really nice and very drivable. In full throttle situations, if the turbo and torque converter are matched properly you will transfer the power at the optimal rpm and boost levels .... and FRY the tires!
Generally, with a higher stall speed you loose some of the drivability that you would have with a lower stall speed. The goal is to get a torque converter that will increase performance without sacrificing drivability. The most important thing to keep in mind, when selecting a torque converter, is that you want to match stall speed to the engine's power band. Many turbo companies will do testing to find out what is the optimum converter for their packages.
As a general rule of thumb ... when the turbo just starts to build boost is really what should determine what stall speed that you will need. The converter needs to have a high enough stall to enable the turbo to spool. As the turbo spools, it will build boost and more power. This added power will increase the stall speed and continue the spooling process. It is not uncommon for a turbo to pull the stall speed of the converter up an additional 500 rpm. If the converter is sized properly with a turbo application, you will get the best of both worlds; a low stall speed for good drivability in off-boost conditions as well as a higher stall under boosted conditions that will give you great performance. With a properly sized converter combined with a turbocharger, it is possible to have your cake and eat it too.
How do I make a final decision on where to buy a torque converter?
The Dealer/Manufacturer should:
Be familiar with your type of power package and done testing with similar vehicle combinations. Offer you as much technical information and product support as possible Offer you a warranty and free stall adjustments. Help you determine what you need from your converter, and then custom build one to your application.
Why a lower stall for diesel applications?
Theoretically, for maximum acceleration, the stall speed of the torque converter should match the peak torque rpm of the engine. Significant gains in throttle response, acceleration, towing and fuel efficiency are possible with a performance diesel torque converter that lowers factory stall speed to where maximum torque is produced. The right torque converter eliminates that "spongy" feel when you step on the accelerator pedal. This reduced converter slippage also results in less heat generation for longer transmission life.
How is the torque converter going to effect the performance of your engine package?
More than likely you have spent an enormous effort making the most amount of power. The torque converter is charged with the job of transferring that power. If you are using inferior OE torque converters with your performance package you are, in essence, wasting that power. A torque converter designed to work in tandem with the engine will put the power back where it belongs - to the wheel.
Why bother with a product that is usually considered an integral part of the drive train not the engine package?
No other component effects the way a motor / vehicle combination makes power like the torque converter. Like every other part of an engine combination the torque converter needs to match the engine curve
What are the important factors that affect Stall Speed?
Vehicle Weight Vane / Fin Angle Horsepower Impeller to Turbine Clearance Powerband / CamShaft Stator Design Input Torque Converter Diameter Gear Ratio