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DRIVING WITH A DOPPELKUPPLUNGSGETRIEBE

Automatics are now so good, gearboxes may soon be history. Paul Markillie is a convert ...

From INTELLIGENT LIFE Magazine, Autumn 2009

A certain type of driver believes real cars have manual gearboxes while automatics are for wimps and Americans. He—it’s usually a he—gets the same satisfaction from rapidly double declutching through the gearbox of a 1953 Jaguar C-type and flicking around the gearstick on a nippy little 2009 Hyundai i10. But now, even drivers who have never owned or desired an automatic are having their prejudices rattled.

The case against driving an automatic used to be strong. They were sluggish, thirsty and expensive, both to fill up and to maintain. An auto might seem soph­isticated in big, lazy cars because it made them easy to drive. Yet the same car with a mechanical gearbox could overtake faster, go through corners with more precision and, because manuals had one or two more gears than an auto, run more economically too. But now some new cars are showing that most of these things are no longer true.

The best example is a Porsche 911. Ever since it was launched at the Frankfurt Motor Show in 1963, the 911 has been something of a drivers’ car. In 1990 it was offered with the option of a new sort of gearbox called a Tiptronic. This was an automatic that could also be driven like a manual, and quite aggressively on a racetrack, by nudging the shift lever forwards to change up or backwards to change down. Now things have moved on again and the latest 911 comes with the option of another remarkable piece of cog-changing equipment: the Doppelkupplungsgetriebe.

It’s more conveniently known as a PDK gearbox, and a good way to try one out is by doodling around town with auto mode selected. As the car in which the PDK comes is a 911 Carrera 4S (the 180mph four-wheel-drive version), a trip to the supermarket is hardly exerting. But it is telling. The Porsche runs so smoothly that it is hard to detect when it is changing gear. And, until the traffic built up, it was showing a fuel consumption of more than 30mpg. Though not impressive in eco terms, this is good for a supercar with a six-cylinder 3.8 litre engine.

As I head back out of town it is time for a different pace. With the auto mode still on, more energetic use of the accelerator produces a character change. This is not the kickdown effect, in which accelerating hard causes a conventional auto to change down. It is much more subtle than that. The Porsche’s computer constantly monitors your driving style: get more forceful with the accelerator and brakes and the point at which it changes gear moves accordingly. Uphill, downhill, into corners, it seems to know exactly what gear to be in. Push harder and as the engine starts to growl the gearbox’s change points enhance the performance.

Want more? Pressing the “Sport” button causes the engine to rev still harder, but now with a bit of a thump in the back when it changes up. And what’s that noise when braking hard into a corner? It’s even blipping the throttle on downshifts. Floor the accelerator and the gears change like lightning as children and shopping disappear into the creases of the back seats. Still want more? There is another button marked “Sport Plus”, but in Britain it’s hard to find a public road to begin to try that out. As this is a German car, perhaps it should be called the “Nürburgring” button.

So what happens when you drive the car properly by manually changing gear? It can be done by nudging the selector lever or racing-driver style with paddles on the steering wheel. But however you do it, you won’t beat the computer. In automatic mode the PDK can change gear faster than any driver can—and without fluffing a gear change. The changes are completed in microseconds, which means there is hardly any interruption in the power being delivered to the wheels.

What makes the PDK different from older auto­matics is that it is, in effect, a manual gearbox being operated by a computer—or rather two manual gearboxes and two clutches combined in one device. This still works out lighter and faster than using a big torque converter, which traditional automatics have. In the PDK, one clutch operates the even gears (second, fourth and sixth) and the other the odd gears (first, third, fifth and seventh). What happens when accelerating in second is that the computer knows third gear is likely to be required next and pre-engages it. The change is then almost instant.

Computer-controlled gearboxes like the PDK are being fitted to a number of new cars. Because they are lighter and more compact, they are also more suitable for small cars, and the ability to programme them for different styles of driving means more consistent and lower fuel-consumption figures when the cars are in normal or economy mode.

Even heavy automatics fitted with torque converters are getting a new lease of life with similar electronic controls. So, to put the macho image of the manual gearbox to rest, I took a Jackal 2 for a spin on an army training ground. This is the latest version of an extreme off-road vehicle built by Supacat, a Devon-based company. Through ponds, up steep sandy hills and flying over ruts, the Jackal 2 is capable of 80mph and preserving your spine with a suspension system made from a cushion of air. Yet it is amazingly easy to drive, because its automatic gearbox does all the clever stuff to make sure you don’t get stuck. In combat that could be fatal. I have to admit it, autos are now the smart choice.

CLEVER SHIFTERS

Porsche 911 Carrera 4S   Latest incarnation of a classic, with PDK gearbox from £75,400 (pictured top)

Fiat 500 1.2   Stylish town car with Dualogic semi-automatic gearbox from £9,130

Mitsubishi Evolution X GSR   Hooligan tendencies with dual-clutch automated manual from £32,999

Audi 3 1.4 SE   Good-looking small car from a big brand, with dual clutch automatic from £18,195

Supacat Jackal 2    Runs rings around a Hummer. Only available with a computerised gearbox, from £200,000 plus armaments
 

(Paul Markillie is innovations editor of The Economist. In past columns he has written about buying a car at auction and when drivers are passengers.)