2005-2014 Mustang Torque Converter Overview
In the S-197 Mustangs there have been two automatic transmissions used: 2005 through 2010 had the 5R55S five speed and 2011 and later Mustangs come with the 6R80 six speed unit. Both are electronically controlled transmission units with lockup torque converters. Like all S-197 Mustangs, the performance of the car with either transmission can be improved with a quality, high stall torque converter. Use the transmission tag identifier if your curious as to whether your Mustang has the stock transmission or not.
What Does a Mustang's Torque Converter Do, and What About Stall Speed?
Torque converters are the link between the Mustang's engine and the transmission. A torque converter's “stall speed” is the rpm at which the converter achieves a hydraulic lock, the point at which the car has to move or cause the engine to stall, although generally a car will never reach that ultimate stall speed. The higher the stall speed the further into the power band the engine can reach without having to move. This allows the car to launch off the line with more power and rpm, greatly reducing the elapsed times at the drag strip.
Is a Torque Converter O.K. for my Daily Driven Mustang?
In short, the answer is yes. In the past, high stall torque converters were not the greatest thing to have in your daily driven street car. They would cause your Mustang to be in a constant state of slippage since the stall speed would be higher than the actual rpm needed to maintain the car's speed on the road. Because of the advent and wide spread usage of “lockup” type torque converters, this slippage is a thing of the past at cruising speed. A lockup torque converter has a large clutch plate inside that is applied by hydraulic pressure in the higher gears as directed by the powertrain control module, effectively locking up the torque converter and making for a solid connection between the motor and transmission. This means you can have your cake and eat it too. You get the high stall torque converter for those great launches at the drag strip as well as the lockup feature for the improved efficiency and mpg at cruise speed. We can all thank the fuel economy gods for this torque converter improvement.
Choosing a Torque Converter For Your Mustang
Choosing the correct high stall torque converter for your Mustang can net you great gains in performance. In many instances there can be a half second or more drop in your quarter mile time. It would take a great deal of engine modifications to match the performance improvement that the high stall torque converter is capable of providing. Getting the correct stall speed to match the power curve of the motor is critical to maximizing the performance. You want a converter that has a stall speed at just the point where the engine is getting to the meat of its power band. Somewhere in the area of 500 to 750 rpm below the torque peak for a max performance application is ideal. A street application can go for something more sedate if you would rarely see the drag strip.
One thing that must also be considered when adding a high stall torque converter to your car is that they do make more heat so it is a good idea to add a transmission oil cooler. This is a simple thing to do and there are many available kits that will more than compensate for the added heat.
All in all, a good high stall torque converter can be one of the best performance modifications for your automatic transmission equipped Mustang!