Audi shifts away from dual clutch transmissions

[Express]

Audi shifts away from dual clutch transmissions


Next-gen RS4 and RS5 likely to run eight-speed automatic


David McCowen
16 June, 2016




Cockpit Audi A5 Coupe. Photo: Supplied


The brand that introduced dual-clutch transmissions to Australia is gradually moving away from the technology for some models.

Audi's first-generation TT V6 was the first car on sale in Australia with a dual-clutch transmission, a feature that has since been adopted by brands ranging from luxury rivals BMW and Mercedes-Benz to economy cars from the likes of Ford and Hyundai.



Audi A5 Coupe. Photo: Supplied


Originally developed for performance cars such as the TT, Volkswagen Golf R32 and Bugatti Veyron, the technology is gradually being withdrawn from high-torque machines in favour of smoother and more reliable torque converter transmissions.

Audi dumped the seven-speed "S-Tronic" dual clutch transmission in the new S4 and S5 performance sedan, wagon and coupe that blends 260kW of power with 500Nm of turbocharged torque. That car features an eight-speed ZF transmission likely to feature in the next-generation RS4 and RS5 performance cars that trade a 4.2-litre naturally aspirated V8 and seven-speed dual-clutch auto for a development of the S4 and S5's high-torque V6.

Florian Beck, powertrain engineer for the new Audi S4 and S5, says the shift is primarily "a torque issue".

"You have to look at the maximum torque. Up to 400Nm is the perfect combination for the dual clutch transmission, but this one has more than 500Nm," he says.

"The new eight-speed transmission is very consistent and very efficient. With eight gears you have very low engine revs while driving. It's the perfect combination of power and efficiency.

"With higher torque combining with tiptronic is the ideal combination... That's the current strategy."

Volkswagen and Audi have had a slightly bumpy road with dual-clutch transmissions, recalling thousands of cars equipped with a dry-clutch seven-speed auto primarily used in low-power applications.

Among its rivals, Ford also shifted away from dual-clutch transmissions and back to a conventional automatic when the latest Focus arrived in 2015 after a spate of issues left thousands of customers with faulty cars.

Dual-clutch transmissions can also be jerker than conventional units, delivering power in an abrupt manner from time to time.

Beck acknowledges that there are low-speed driveability benefits to the shift away from dual-clutch transmissions.

"With a torque converter it helps for the takeoff. And of course it's very important to calibrate the whole power train, it has to work together," he says.

"You have to find the perfect blend between dynamics, efficiency and comfort.

"The eight-speed transmission is the perfect combination."

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