First drive: Porsche to hunt with V8 diesel Cayenne

PORSCHE Cars Australia (PCA) is a little unsure what sales volumes to predict for its first V8 diesel offering – the locomotive-like Cayenne S Diesel large SUV – that is due to rewrite the diesel SUV record books when it arrives Down Under in April next year.

However, it expects most buyers to be conquested from other European brands, drawn by big performance figures and the Porsche badge.

Offering a class-leading 850Nm of torque – 110Nm more than BMW’s V8 diesel X6 M50d – along with 281kW of power from its Audi-sourced 4.2-litre biturbo engine, the barrel-chested Cayenne is being billed as a high-performance diesel SUV, supported by figures that show it can dash from zero to 100km/h in 5.7 seconds and top 250km/h on the autobahns of Europe.

It is 1.9 seconds faster to the 100km/h benchmark than the previous sole diesel offering in the Cayenne line-up, the 3.0-litre V6, yet still manages to deliver a combined fuel economy reading of 8.3 litres per 100km.

However, the stump-ripping engine comes at a cost, with buyers to pay a premium of $3600 for the $155,400 Cayenne V8 diesel over the otherwise identical V8 petrol Cayenne S.

While PCA is unsure if many dyed-in-the-wool Porsche owners will make the switch to the V8 diesel when a cheaper petrol V8 model is already in the showroom – despite the better fuel economy – customers used to diesels in other European brands might be tempted to make the switch.

The Audi Q7-based Cayenne is by far Porsche’s biggest seller in Australia, accounting for more than half of all local sales by the Stuttgart-based performance car-builder which expects to shift about 1350 cars in Australia this year – about the same as last year.

The new flagship Cayenne diesel model is distinguished from its petrol equivalent only by subtle ‘diesel’ badges on the flanks, and like the petrol Cayenne S, comes standard with an eight-speed Tiptronic torque converter automatic transmission.

Unfortunately for Porsche, the admirable 8.3L/100km fuel consumption figure is still too high to qualify for luxury car tax breaks for fuel-efficient vehicles, which apply to some other European-sourced diesel vehicles.

Potential buyers need not fear that the Cayenne S Diesel will sound and perform like a traditional smoke-blowing truck-like diesel, with the big V8 instilled with the most petrol-like qualities of any diesel in our experience.

Driving the big beast at the global launch in Austria this week, the immediate impression was that the vehicle sounded little different from Porsche’s petrol Cayenne S, with its engineers not only ridding the engine of the tack-a-tack diesel rattle but supplanting it with a glorious V8 exhaust note that penetrates the cabin whenever the accelerator pedal is floored.

These engineers boast that they achieved this effect without any “synthetic fiddling”, while also adding another layer of performance over the donor engine from Audi to create what they describe as an “emotional sports car”.

The extra grunt was mainly achieved by ramping up the turbo boost and improving the intercooler and exhaust systems for better breathing to gain 23kW and 50Nm over the standard Audi engine used in the Q7 SUV and A8 limousine.

Special engine valves, pistons and other tidbits were added to cope with the enormous forces generated by the engine, which drives all four wheels through Porsche’s all-wheel-drive system shared with the German’s company’s other debutante in Europe this week, the 911 Carrera 4.

This system can shift the torque between the rear axle – the default setting – and front wheels, according to need on slippery surfaces or under hard acceleration.

While the Cayenne S Diesel does accelerate hard, the effect is more like the aforementioned locomotive, building up a head of steam rather than the rush of, say, a turbocharged petrol sportscar.

This performance is best demonstrated in passing manoeuvres – a tricky undertaking on Austria’s narrow and winding roads – when the big SUV kicks down several gears and just blasts around slow-moving traffic.

The handling performance of the test vehicle was blunted by mandatory snow tyres that lack the grip of the rubber we will see here, but the chassis clearly is not just competent but outstanding.

Even on roads made wet and slippery by autumn snowfall a day earlier, the Cayenne S Diesel handled and steered with more competence than many smaller passenger cars.

Australian buyers will get the adjustable air suspension as standard equipment (optional in Europe), to further enhance the driving experience.

This suspension has been retuned for the heavier diesel engine in the nose of the car.

All Cayennes get two driving modes – normal and sport – that can be chosen by the press of a button. These change the shift characteristics of the automatic transmission, which also boasts fuel-saving idle-stop – a first for a diesel V8 SUV – and hill-descent control.

Customers can add a torque vectoring system to further enhance the handling by automatically braking individual wheels.

In the faint chance that a Cayenne S Diesel owner will take their vehicle off-road, three off-road modes are offered, operated by one of no fewer than 60 switches, knobs and buttons adorning the driver’s cockpit.

New options include adaptive cruise control, an active headlight system and the Sport Chrono system that even includes a stop-watch in the dash for ultra-keen SUV drivers.

Despite its thumping performance, the V8 diesel is not Porsche’s highest-performing Cayenne, with the V8 petrol GTS (0-100km/h in 5.4 seconds) and Cayenne Turbo (4.7 seconds), leading the pack.

The arrival of the S Diesel next year will bring the Cayenne range to seven models, ranging in price from the $109,400 Cayenne V6 to the flagship twin-turbo V8 Cayenne Turbo at $247,500.

2013 Porsche Cayenne S Diesel pricing*

S Diesel	$155,500

*Plus on-road costs