In the mid 1960s Porsche’s development work on an auto box for VW prompted renewed interest in a clutchless transmission for the 911. Ferry was against a full automatic, not part of the pure sports car image, and in any case transaxles for automatics were undeveloped. Porsche’s route was a clutchless manual which used a hydraulic torque converter replacing the conventional flywheel and mated to a four speed 901 gearbox. NSU’S Ro80 had a similar transmission. On the 911 the torque converter used oil from the engine supply and the converter allowed the motor to idle without stalling while a clutch operated by a vacuum servo intervened only to break the drive. As it did not have to absorb the power and heat generated by taking up drive, a task undertaken by the torque converter, a special, lighter 7.5 inch clutchplate was fitted. Inside there was no third pedal and the gearlever activated a switch which disengaged the clutch enabling shifting without engagement of the driver’s left foot. The multiplication effect of the torque converter effectively lengthened the ‘range’ of each gear, so four forward speeds more than sufficed.
The Sportomatic was greeted sceptically by the US auto press, but the Europeans were impressed, generally finding that speed of gearshifting almost made up for torque converter losses in acceleration. Porsche would sell more Sportos in Europe than it predicted and the Sportomatic remained an option to the end of the 3.0 Carrera in 1977, by which time it had been reworked as a three-speed for the greater torque of the bigger engine. According to some accounts, Sportomatic transmission could still be ordered until 1980. WHERE Phil Raby Porsche IS IT? is at Southbourne, off the A27 between philraby.co.uk Portsmouth 01243 and 780389 Chichester. FOR Very rare model, comprehensive rebuild, eminently usable AGAINST An expensive curiosity; may not suit all tastes VERDICT For the serious collector, a superior Sportomatic might take years to find. Enjoy this one now!