According to Chevy's web page (and my recall) the Volt has 273 ft-lbs of torque.
According to Tesla's web page the Roadster has 273 ft-lbs and the Roadster Sport has 295 ft-lbs.
Likewise a Volt's 111 kW motor compared to the Tesla's 215 kW motor.
Are you perhaps referring to a previous model of the Roadster? Do you really think a Volt's drive train out powers a Roadster's