Testing, testing...

I've just spent a day on the road with the Porsche engineers testing the final prototypes of the new Porsche Cayenne, which is due to be launched at the end of February. And, as you would expect, the new version is due to raise the benchmark for "performance" SUVs even further...

Though still disguised with strategically positioned tape, the three test vehicles, a black Cayenne S V8, a white Cayenne Turbo and a black Cayenne hybrid, were immediately recognisable to most of the onlookers we met on our trip from OR Tambo Airport through Pretoria to the Magaliesberge...

But, though the vehicles were immediately recognisable as Cayennes, it was only the lucky few who got up really close who were able to make out styling details such as the large, Panamera-style rear lights, the new headlights (which have reverted to the traditional Porsche style) and the revised bonnet-line, which is now similar in shape to those of the Boxster, 911 and Panamera.

So, in looks, the Cayenne is even more Porsche than before... And, though it looks more compact than its predecessor, it is actually longer, with a longer wheelbase. That translates to more interior space, and has allowed the use of a sliding rear seat, which allows occupants to choose between extra legroom and more luggage space.

Another immediately noticeable change is in the design language of the facia and centre console, which also now have a Porsche family look, echoing those of the Panamera.

True to Porsche tradition, the new V8 and Turbo are more powerful and faster than their predecessors... But they're also lighter and more economical. In fact the new Turbo is claimed to be 25 per cent less thirsty than the current version.

Of course, the economy tour de force comes from the hybrid, which uses a supercharged 245 kW 3,0-litre V6 (the unit from the Audi S4) coupled with an electric motor that produces 38 kW, making it a full hybrid, not a mild hybrid as is the case with new petrol-electric Mercedes S-Class and BMW 7 Series models. Total power output is not far off the Cayenne S.

Porsche's hybrid system is interesting in that it uses an electronically controlled clutch to decouple the eight-speed Aisin gearbox from the petrol engine at speeds up to 158 km/h, allowing momentum to be maintained by the electric motor alone. Porsche uses the word "sailing" to describe this coasting process. When the power of the petrol engine is needed, the electronics control the engagement of the clutch (which has to take place in a fraction of a second), ensuring a seamless transition.

For the full story of my day on the road, you'll have to wait for the March issue of CAR, on sale from February 22...