All-torque, no action, for seven-speed DSG

Volkswagen wants DSG available as an option for the entire product range eventually (with the apparent exception of Bluemotion models!), but the company is in a quandary of its own making where the seven-speed DSG is concerned. The seven-speed box suitable for transverse applications is being rolled out locally in models from Volkswagen, Audi and Skoda, but it's blighted by an effective torque ceiling of 250Nm -- with no likelihood in the immediate near future of any upgrade to handle higher torque figures.

Volkswagen's Product Communications spokesperson, Christian Haacke explains: "The seven-speed DSG was aimed from the beginning at smaller-torque engines, and therefore we knew we could reduce weight by keeping out the oil-cooling for the car [which] would... benefit from the improved mileage.

"The seven-speed DSG was aimed from the start at 250Nm limitation. Because we could spare the oil cooling and have the advantage of reduced friction and therefore better mileage, because the clutches don't have to overcome the oil..."

But wouldn't the efficiency losses through friction be offset by the extra gear, allowing Volkswagen to specify a higher final drive ratio and thus reduce fuel consumption on the open road?

"It's always a question of a well-balanced package," answers Haacke.

"From a technological point of view, for example with the [Bugatti] Veyron, with a seven-speed DSG... You need a larger oil volume for cooling purposes and therefore you would have a weight increase -- and there goes the well-balanced package.

"Even today, with the Polo with seven-speed DSG, we're looking at a weight disadvantage of around about 20 kilos; and that's a lot, with a small car like this -- if you remember that Professor Heitzmann [Volkswagen board member] pointed out proudly that we were able to reduce weight by 25 kilos."

So the running cost and leaner efficiency benefits of the seven-speed box available in the new Polo are offset by its relative lack of durability -- a factor arising out of its lightweight build, which improves efficiency and lowers running costs! Talk about a vicious coupling...

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