Auto Extreme

Details of the new 7-speed dual-clutch S-tronic gearbox has been released by Audi for no interruptions in power delivery during shifting. Operating just like VW’s DSG gearbox, but with an extra cog, the S-tronic is built by Borg Warner. It is due to debut in the upcoming Q5 SUV later on this year. The new transmission has been designed for use with Audi’s longitudinally mounted engines and Quattro all-wheel drive system, and is capable of handling up 406 lb-ft of torque and engine speeds up to 9,000rpm.

The new twin-clutch transmission is designed to work with longitudinally installed engines and the quattro all-wheel drive system, with its 550 Nm torque capacity making it suitable for a wide range of sporty models. As with the outgoing S tronic gearbox, Audi drivers can use the new seven-speed S tronic in various modes. The fully automatic mode, in which the computer selects the gear, keeps the D (Drive) and S (Sport) programs available. The gears can also be manually switched with the shift selector lever or with the optional rocker switch on the steering wheel.

The gearbox uses two multi-disk clutches, with a larger, ring-shaped one operating odd gears including first, third, fifth and seventh via a solid shaft while a smaller clutch inside the ring clutch operates second, fourth, sixth as well as reverse via a hollow shaft that surrounds the solid shaft. While one clutch is locked into a gear, the other clutch is ready to engage, with shift speeds that Audi claims are in the few hundredths of a second, with an imperceptible affect on traction.

The S-tronic will send 40 percent of engine torque to the front axle and 60 to the rear under ideal conditions. An integrated center differential can allocate up to 65 percent to the front, or 85 percent to the rear axle. For durability, gears one through three and reverse use three-cone synchros. The transmission can be left in fully automatic mode in either Drive or Sport, or the gear can be selected via pushbuttons on the steering wheel.

The Q5 will be unveiled in April at the Beijing auto show and will be the first of multiple Audi models released this year using the transmission.

Audi’s first production dual clutch transmission was used in the 2004 Audi TT. Its six speeds put down the power of the car’s 250 horsepower V6 engine.

You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.