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- Stall Converters
Which one is right for you?
First ask yourself what do I expect out my stall converter?
What is Stall speed and what is the difference between foot break stall and flash stall?
Foot break stall is the measurement of stall at which your drivewheels break loose while on your your throttle and depressing your break pedal at the same time. A 3000 speed stall converter will typically break the tires loose around 2200-2400 rpm.
Flash stall is another way to measure stall speed and can be tested by launching your car in 2nd and monitoring your tachometer for a brief hesitation. That slight pause of the tach will display your flash stall RPM.
How much power lbs/ft and HP along with weight of your vehicle is a great place to start.
Let's take a look at the ever popular 700R4 through the later generation GM 4L60E and ultimately to its last 4L65E and 4L70E.
Part I: Understanding Torque Converter Stall Speed:
In order for our customer's to make informed decisions, we feel that is important for them to know what they are shopping for. After reading this post, you should have a basic idea of what stall speeds are and how to select the right stall speed for your desired driving style.
Stall speed and stall speed selection are terms that are frequently misused and misunderstood when shopping for a torque converter. Most of the time they are confused with other elements of a torque converter or not measured properly. Even seasoned car enthusiasts are guilty. However, there is no need to fear, the professionals at Phoenix Performance Torque Converters are here to clarify.
What is Stall Speed?
Stall speed is the speed at which the converter holds back or limits the engine speed if the transmission output is prohibited. When your torque converter prevents the power transfer from your engine to your transmission, it increases the engine's RPM stalls.
Why is Torque Converter Stall Speed Important?
High performance torque converters, like to ones sold at Phoenix Performance Torque Converters, can do a lot for your vehicle when the proper stall speed is selected.
For racing, the proper stall speed will increase your launch and get you off the line quicker. On the flip side the proper stall speed will help your diesel engine pass more power to your transmission, causing your tow capacity to increase.
How To Choose the Right Stall Speed
When you are selecting the right stall speed for your vehicle, be sure to match the engine's peak torque, torque curve and vehicle weight.
- Peak Torque - The maximum torque your engine can exert at a certain RPM.
- Torque Curve - The place where the engine has the maximum amount of power at a certain RPM.
- Vehicle Weight - The weight of your vehicle has a big impact on the measurement, and don't forget to factor in aftermarket modifications.
Do you make extra power by using power boosters such as NOS, turbos, or a supercharger?
If you don't know these exact specifications, we recommend giving a conservative estimate. If you over estimate your torque lbs/ft, Horsepower your stall speed will be lower than intended, which will reduce your torque converter's performance. If you are unsure about these modifications, the experts at Phoenix Performance Torque Converters can help.
For race applications the common rule of thumb is to set the stall speed 500-700 RPM below the engine's peak torque and HP curve. This ensures a margin for application for the torque converter to take off. You don't want to have to floor your gas pedal and wait a few seconds for your vehicle to move. Think of it as a balancing act.
For a a street strip application possibly even your daily driver the desired stall speed is significantly lower than your peak engine torque and horsepower. A street strip performance stall converter takes into account driveability along with massive performance gains. Most of our gas street strip customers are happy in the 2800-3400 range.
For help choosing the right stall don't be afraid to call us at 727-541-0269 and we will get your questions answered.