Re: Ultramatic blade upgrade?

Posted by Tim Cole On 2014/6/21 7:41:09

The 2.7:1 torque multiplication is pretty much a practical limit. Units like the 727 TorqueFlite used 2.2:1 because they would have trouble reaching coupling phase with a higher ratio. Packard avoided that problem through the lock up clutch - thus the name "Ultra".

The other big factor is stall speed which is determined mostly by converter diameter. Stall speed is chosen to match optimum torque output for a given motor. Thus, racing motors have higher stall speeds.

The principal deficiency in the Packard converter is the second turbine. Early on the practice was to have multiple turbines - Dynaflow and Powerglide started with five. Later they discovered all those turbines did was generate excessive slip.