What is it?
This is the Porsche Cayenne Diesel, a car that Porsche’s chairman, Wendelin Wiedeking, once proclaimed the company would never build. The Porsche Cayenne Diesel slots neatly between the base Porsche Cayenne and the Porsche Cayenne S. The Cayenne Diesel also marks a radical departure for Porsche, being its first-ever production diesel car.
Not that you’re likely to notice. Porsche clearly remains uncomfortable about introducing a diesel, so the Porsche Cayenne Diesel is visually identical to the base Cayenne. There’s not even a badge to give the game away.
It is not until you climb behind the Porsche Cayenne Diesel’s three-spoke steering wheel that you are confronted with the first clues to the turbocharged 3.0-litre V6 common-rail diesel engine under the bonnet.
First up, there is the rev counter that reaches to just 4600rpm. There’s also the characteristic diesel chatter on start-up. It is not the sort of sound you normally associate with a Porsche, but given that the Cayenne is closely related to the Volkswagen Touareg and Audi Q7 – alongside which it is partly assembled – it is not surprising. Not when three quarters of all big off-roaders sold across Europe last year were diesel.
You won’t find any mention of Audi’s Gyor factory in Hungary in the press kit. But that’s where the Cayenne diesel’s engine is produced. With piezo-controlled injector valves that enable the fuel to be delivered to each cylinder at 1800bar of pressure and a variable-geometry turbocharger, the unit kicks out 240bhp at 4000rpm and 405lb ft of torque at 2000rpm.
What’s it like?
While lacking the inherent refinement and enthusiasm of BMW’s standard-setting twin-turbocharged 3.0-litre straight six, the Audi-sourced motor in the Porsche Cayenne Diesel is reasonably smooth and offers decent in-gear poke. It’s a pity the V6 diesel is so vocal, though.
The six-speed auto, an Aisin unit modified to handle the torque of the engine, is decisive, fast and smooth. It provides a broad spread of performance. Strong low-end acceleration combines with excellent cruising qualities to make the Cayenne Diesel a very rounded proposition. Flick the Sport button and the changes are set significantly quicker, while the throttle response is also sharpened.
At 2240kg, the Porsche Cayenne Diesel is no featherweight. Still, Porsche is proud that it has been able to peg the increase over the petrol Cayenne at just 70kg – included in which is an additional 26kg in engine weight, 29kg of sound deadening and 13kg in a beefed-up torque converter. Odd, then, that its claimed 0-62mph time of 8.3sec is exactly the same as the similarly powered Volkswagen Touareg, which is lumbered with a further 90kg.
The Porsche cayenne Diesel’s 133mph top speed is 3mph quicker than its sibling’s, thanks to more favourable aerodynamics and a smaller frontal area. And with combined fuel consumption of more than 30mpg and a CO2 rating of 244g/km (providing it with EU4 compatibility), this is easily the most economical and cleanest model in the Cayenne line-up.
For such a big car the Cayenne Diesel’s handling is composed, the added weight of the engine and associated changes barely noticeable on open back roads. And with all that torque and four-wheel drive to exploit it, you can confidently stomp out of bends with all the enthusiasm of larger petrol engine Cayenne models.