Tesla Motors has completed development for what its has called “Powertrain 1.5” (earlier post)—the enhanced powertrain with higher current and torque, using a single-speed transmission to achieve the original performance spec.
Tesla began working on Powertrain 1.5 after announcing a delay last year due to problems with the previous two-speed transmission. The design work being done, Tesla has selected BorgWarner to manufacture the single-speed gearbox. Tesla has been working with them since early this year.
The new powertrain delivers about 30% higher motor torque on the single gear ratio, and it achieves a 10% higher EPA combined rating of 244 miles per charge. Torque increases 33% from 211 lb-ft (286 Nm) to 280 lb-ft (380 Nm).
Last December, when the two-speed transmission designed by a previous supplier proved not to be durable, we announced we would modify our approach. By using a more powerful inverter and an enhanced motor design, we were able to implement a single-speed gearbox and still achieve our original performance goals. In fact, the new setup is superior in almost every way.—JB Straubel, Chief Technology Officer of Tesla Motors
The enhanced powertrain setup is now being inserted into the production process, which is being ramped up. So far, 27 customers have taken delivery of Roadsters. More than 50 cars have been started on the production line in total to date. With the enhanced powertrain ready, production will ramp up from 4 starts per week to 10 starts per week. This will increase to 20 per week by December and to maximum capacity of about 40 cars per week by March 2009.