The Dummy Torque Converter
The impeller pump has been...
The impeller pump has been modified to remove all of the internalcomponents. It is then welded to the cover for the final assembly. It iseasy to understand the value of losing all of that rotating weight.
Basically, a dummy torque converter consistsonly of a direct front pump drive inside a "gutted out" converter. Astock-working converter consists of the impeller, the stator, theturbine, and the front. The fins are removed from the impeller, and thestator and turbine are removed. The direct front pump drive is welded tothe front, and then the top is welded to the front.
The hub part of thedirect drive extends through the top, and they are welded together, thusgiving it the appearance of a normal converter. These units can be builtout of any converter core size, but the 10- and 11-inch converters aremore common. A stock-working converter can have on the average 8-10percent slippage, whereas a dummy converter has zero. The application ofpower is instantaneous.
Even an aftermarket "low stall speed" converterdesigned for a circle track application has some slippage, so all inall, you can't get any better lockup than the dummy converter. The dummyunit will hold fluid, and it will get hot just like normal fluid, but ithas no fluid actually circulating through it.
TCI installs a drain plugin the converter to allow the racer to fill the converter with fluid.The weight difference of a working converter and a dummy unit is a majorconsideration. A normal working 10-inch converter weighs 28-29 pounds,whereas a dummy converter weighs only 16 pounds. The 11-inch model hasabout the same difference in weight variance.
Less rotating weight andzero slippage mean quicker acceleration out of the corners and down thestraightaway. The fact that the unit is basically locked up helps toprovide better engine braking. When you get off the throttle, it helpsto set the car going into the corners so you can drive deeper into theturns.
Another advantage is that there are no moving parts inside adummy converter to wear out or break. To use the dummy converter, youneed a direct-drive style transmission. The Powerglide is the mostcommon automatic used in circle track racing because it has lessrotating weight than any other automatic transmission, and even lessthan that of a manual transmission.
With the TCI "clutch-less" stylePowerglide, all you need to do is put it in gear and go. You can upshifton the fly and restart in low gear. With a dummy torque converter, youwill have instant throttle response. That could be a huge plus when thegreen flag drops.
This article originally printed in March 2005