Cayenne is first ever diesel Porsche

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What is it?

You're looking at the very first diesel-powered Porsche to go on sale. Such a thing may have been frowned upon not so long ago, but the world has moved on. Diesel technology has arguably advanced faster than petrol power in recent years and in today's world even buyers of luxury SUVs need to consider their running costs and effect on the environment. Porsche isn't being all magnanimous by producing the Cayenne Diesel either, as in Europe this year up to 90% of SUVs sold will be powered by diesel engines, so it would be foolish not to compete for that business.

As the Cayenne was developed at the same time as VW's Touareg, it made more sense for Porsche to pilfer an existing engine than to spend a fortune developing its own. The chosen unit is a 3.0-litre V6 with a variable geometry turbocharger. Porsche hasn't made any major modifications to the engine itself though the Cayenne has received a few alterations.

You'll not spot the difference on the outside between the Cayenne Diesel and its petrol-powered V6 alternative, which is exactly how Porsche wanted it. On the inside the only telltale sign is a rev counter with a lower red line, though Porsche has also replaced the windscreen with a thicker item to suppress clatter from the diesel engine.

Is it any good?

Anyone familiar with Porsche's Cayenne will instantly feel at home in the new Diesel model. It pretty much makes the V6 petrol variant obsolete, as it outperforms it where it matters, uses a lot less fuel and emits much less CO₂. At idle, you'll only tell it's diesel powered from the outside and the engine is only really audible from inside when you push the V6 towards the redline. Peak power is an adequate 236bhp, but it's the maximum torque figure of 406lb.ft that defines how this Cayenne drives, as it endows the big SUV with effortless pace and a massive 3,500kg towing capacity.

Although the Cayenne Diesel isn't fast in an exciting way, it is rapid by most standards and the six-speed automatic gearbox suits its lazier power delivery to a tee. If you fancy driving a little harder, there's even a large Sport button, which changes the throttle and gearchange strategies, as well as firming up the air suspension. As with all Cayennes, this model feels remarkably agile, which is completely at odds with the significant kerb weight.

Potential rivals (Cayenne V6 petrol aside) include BMW's X6, the TDV6 Range Rover Sport and of course the VW Touareg that shares the same engine as the Cayenne. The Porsche compares well to all of these, though BMW boasts the most impressive fuel economy and emissions and runs the Cayenne close in terms of dynamics.

Should I call the bank manager?

At £39,404, this is a remarkably good value Porsche, so it shouldn't take too much convincing. If the bank manager points out that the petrol V6 is still £3,000 cheaper, you can mention that the Diesel model comes as standard with the more expensive Tiptronic S transmission and that it ducks under the forthcoming most expensive rate of vehicle excise duty thanks to its 244g/km of CO₂ figure. If negotiations get tough, you can resort to quoting the vastly improved fuel consumption.

Summary

Porsche purists won't approve of the Cayenne Diesel one little bit, but they should rejoice at its creation, as it is sure to add to the company's continued sales success, hence allowing it to continue to produce the iconic sportscars we all love. The large SUV buyer will also be happy that it's easier to justify buying a Porsche Cayenne now, as the Diesel model retains all the cachet of its petrol brethren, but with lower running costs. It makes us wonder why Porsche is continuing to offer the entry-level V6 petrol model at all.

Shane O' Donoghue