21 Feb 06
Sand is unlike any other off-road medium. Care and caution don't get you where you want to go in sand: they get you stuck. Mud offers up precious little for the tyres to grip against - which is why a little, light car like a Jimny will always beat a Cayenne-type car in that environment: narrow tyres cut through the slime better than fat ones, you don't need the extra power and you have half the weight to persuade to change direction.
In the sand, precisely the reverse is true. One thing and one thing alone keeps you going in the desert: momentum. And as any GCSE physics student will tell you, to acquire momentum you need both power and weight. You begin to see why the Cayenne might be quite good at this. Fat tyres also help enormously because they spread the load over a wide area of sand, reducing the chance of you sinking into it.
And in this most hostile of environments, the idea of a 521bhp SUV suddenly makes perfect sense. To deal with the average Arabian desert dune you start with the car parked just over the lip, nose pointing at the floor of the dune. The sand has so much drag, brakes are near enough redundant out here: even if you're going down a steep hill, if you take your foot off the gas, you stop. Do so on the level and you'll face half an hour's sweaty shovelling before you're mobile again. But parked downhill, you simply apply a little throttle and let gravity do the rest.
Approaching the bottom of the dune though, you'll need the 4.5-litre twin turbo to give everything it's got. Traction control disconnected, you bellow down to the floor of the dune as fast as conceivably possible and rely upon the power of the engine and the four vast, 20" windmilling wheels to propel the whole rig across the dune and, you hope, up and over the other side. This manoeuvre is executed in one perpetual slide and feels more like having your own personal hydroplane than anything related to dry earth. It is exhilarating, almost beyond expression. I'm not an experienced desert off-roader - in fact, I suspect I'm rather bad at it - but I still can't conceive of another entirely standard production car that could do this quite as well as the Cayenne Turbo S.
