Tesla Pins Down New Transmission, Promises "Hundreds" of Roadsters Soon
By John O'Dell September 9, 2008
By John O'Dell, Senior Editor
Electric vehicle pioneer Tesla Motors, which has delivered the first 27 of its $100,000-plus electric roadsters with an admittedly jury-rigged transmission, said it finally has nailed down specifications for a new gearbox.
The new single-speed transmission, to be manufactured by BorgWarner, is a central part of an enhanced system Tesla has dubbed "powertrain 1.5."
It includes an improved electric motor design, the new Tesla transmission and a more powerful inverter and, the EV maker says, delivers 30 percent more motor torque and a 10 percent improvement in range on the EPA's combined city and highway cycle.
"Last December, when the two-speed transmission designed by a previous supplier proved not to be durable, we announced we would modify our approach," said JB Straubel, Tesla's chief technology officer.
The company also decided at that time to begin shipping cars with an interim transmission in order to avoid a lengthy delay that would disrupt cash flow and potentially anger some buyers who'd been waiting months for their cars after two earlier production postponements.
The new gearbox is designed for the higher peak torque levels of the new Roadster powertrain. Torque has been boosted to 280 pound-feet (380 Newton-meters) from 211 pound-feet (286 Newton-meters).
Cars equipped with the new powertrain will achieve an EPA combined range of 244 miles on a single charge of the their lithium-ion battery packs, up from 221 miles with the original powertrain.
Production of Tesla's zero-emission roadsters (right)
began in March and the initial cars were shipped with the low range removed from the original two-speed transmission and the promise that Tesla would replace it with a new, durable transmission it was designing.
The company said Tuesday it will make good on that promise, replacing the interim transmissions and the original inverters and motors with "powertrain 1.5" at no charge to customers.
The old transmissions will be installed on 11 more cars to will be built before BorgWarner can start turning out the new model, so Tesla will replace 38 in all, said Darryl Siry, senior vice president of sales, marketing and service.
Tesla also said Tuesday that production, which began with one car per week, has been ramping up with 10 new roadsters now starting the four-to-six-week production process each week.
The company said it expects production starts to hit 40 per week by early next year and Chief Executive Ze'ev Drori said in a statement Tuesday that, with the new powertrain, "in a matter of months there will be hundreds of Tesla roadsters across the country."
Completion of work on the new transmission will free a lot of Tesla's engineering talent to work on the company's next project, a family-size electric sedan, to be produced in California and marketed globally.
The company is aiming for a starting price of $60,000 on the base version of what it is now calling the "Model S" sedan.
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