Myth Busters, Part 2

Last month we reviewed the results of chassis dyno testing done by Sean Boyle’s students in the automatic transmission class at Southern Illinois University. Four modified torque converters were evaluated. The testing was done on a MD-250 Mustang Chassis Dyno, and the test vehicle was a stock 2000 Dodge Durango RT equipped with a 5.9L gas engine and a 46RE transmission.

The converter replacement was the only change made to the vehicle, and only one modification was done to the converter for each test. In Part I of this series, converter A had a modified stator – .250” had been machined from the impeller side of the stator, and this modification lowered the stall of the converter. The test vehicle responded favorably to this modification, which would have helped the vehicle’s towing capabilities and probably enhanced fuel economy.

This month we look at how converter B tested. Converter B also had a modified stator. The difference is that in this converter, .175″ was machined f rom the turbine side of the stator. (Figure 1 shows the modified stator below an OEM stator.) This particular modification is popular on performance converters to increase stall. Since no brake stall test or timed acceleration test was performed for these evaluations, there was no measurable increase in stall. When you compare the graphs of the OEM converter vs. modified converter B in the overlay in Figure 2, you can see that the horsepower and torque readings for both converters start at about 2300 rpms. You can also see that the horsepower and torque readings of the modified converter B remained below the readings of the OEM converter throughout the run. When you do line-by-line comparisons of the OEM vs. the modified B converter at specific rpms, you see dramatic differences (see Figure 3).

To read the rest of this Technical Article on the Sonnax Website click here.

Article No.: TCTIP-06-06
Author: Ed Lee
Total Pages: 2

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