GM 6L80 and 6L90 gas-powered applications that use a full-size torque converter often have engine modifications for increased output, towing heavy loads, or both, which can quickly push the stock single-disc converter clutch past its capacity. To add strength and durability to stock converters, Sonnax offers forged front cover GM-CC-13 and piston plate GM-DA-17P.

For customers with more demanding applications, Sonnax offers performance converter kit GM-RK-21. Employing a forged cover, forged piston and three woven carbon friction elements, builders now have a dampered 300mm multi-plate option that delivers significantly increased clutch capacity and durability. By re-using the OE damper with the Sonnax clutch plates (bonded with OE woven carbon friction material), GM-RK-21 ensures optimal TCC apply and release characteristics, as well as slip rates that match OE continuous slip calibrations. Drivability is excellent. This easy-to-build and cost-effective kit includes clear, concise instructions.

While testing this kit, Sonnax found that the pressure needed to keep this multi-plate TCC slipping at the calibrated rate was much less than the pressure needed in a comparable single-disc converter. Because the Sonnax multi-plate clutch needs less pressure, there is less demand placed on transmission electronics and hydraulics. With the GM-RK-21, it’s easy for the transmission to keep the TCC slip within required slip parameters.

Enhanced design features include:

• OE friction material bonded to each clutch plate
• Forged components assure rigid apply and reaction surfaces
• Lathe turned feature on mount pads identifies this kit as a multi-plate
• Added clutch capacity reduces required lockup pressure
• Lower operating pressure reduces demand on transmission electronics and hydraulics