First Oz drive: Audi's diesel debut

IT may be the big thing in Europe, but in Australia diesel engines are not a mainstream powerplant for car buyers.

But the situation is changing. Cleaner diesel fuel with a much lower sulphur content becomes mandatory here from January 1, 2003, and that is prompting increased interest in this form of motivation.

In this case it is Audi dabbing its toe in the diesel waters for the first time in Australia with the Allroad quattro TDI, although it has been marketing diesel engines with great success in Europe for the past 12 years.

Being an Audi, the quad cam, 2.5-litre V6 is something of a techno tour de force of course high pressure direct injection for smoother performance (TDI actually stands for turbo direct injection) a turbo nestling between the 90-degree alloy cylinder banks which eschews a wastegate in favour of adjustable vanes for superior low-rev running and twin converters for improved emissions performance, enabling the engine to exceed the tough Euro Step III regulations.

Performance figures are impressive as a result. Maximum power is 132kW at 4000rpm and maximum torque a whopping 370Nm between 1500rpm and 2500rpm. Audi claims a 0-100km/h acceleration figure of 10.2 seconds, a top speed of 205km/h and an average fuel consumption figure of 9.6L/100km.

Pretty impressive stuff. But the figure that may set you back is the pricetag, even though at $88,500 it is about $10,000 cheaper than the 2.7-litre bi-turbo Allroad that has been the sole offering until now.

Audi Australia actually says this is a pretty good price because diesels usually command a price premium. Some hard work went in at the factory to turn the equation around in this case.

But line it up against the 3.0 turbo-diesel BMW X5 expected in January for about $80,000 and the Mercedes-Benz ML270CDI which is a relative bargain at $67,900, and the Allroad has set itself a real challenge on a comparative value for dollar basis.

Realistically then, Audi Australia is shooting low when it comes to sales performance - just 100 TDIs between June and December this year and 200 in the full year 2003. That compares to 120 in both years for the bi-turbo.

Some of the cost saving has been eked out by deleting Xenon headlights, the sunroof and acoustic parking sensors from the standard equipment list. The airbag count also drops from eight to six.

Wood trim is traded in for aluminium, the former remaining as an option along with a more sophisticated CD-audio system, sat-nav and a third row children's bench seat. But leather interior trim remains standard along with dual zone climate control, a trip computer and remote central locking.

Mechanically, the basics remain the same. The engine is mated to a five-speed Tiptronic transmission with the choice of full auto operation or semi-manual self-shifting, power and torque are transferred via an all-wheel drive system which employs a Torsen centre differential and electronic differential lock upfront, with the electronic stability program providing further support.

Recognising the off-road intentions of the car, it is equipped with four-stage air suspension, which provides as much as 208mm of ground clearance and as little as 142mm. That is mated to Audi's four-link system up-front and double wishbones at the rear.

But there is still a lot of road car in the Allroad, its styling lines clearly linked to its donor sibling, the A6 Avant, even if its looks have been toughened up with ribbed undertrays, big bumpers and flared wheel arches.

DRIVE IMPRESSIONS:

Rattle-rattle-rattle. That's the first thing you hear when you fire up the Allroad TDI, but only if you have the power windows down.

From the outside, this car issues the traditional diesel sounds, but inside such is the excellence of the noise deadening you would not have a clue most of the time.

But hit the throttle and you get the hint big-time. The launch behaviour of the TDI is truly excellent in low gears, giving this car a strong, flexible feel at low speeds despite its 1825kg kerb weight.

The good news is it keeps going strongly and confidently as speeds rise, still pulling hard to speeds that are illegal everywhere in Australia except the Northern Territory.

Being set-up for some off-road use, the Allroad is not as focussed as the A6 on bitumen, feeling a little floatier through high-speed turns with a tendency for more bodyroll, however it is well ahead of any serious off-roader. The trade-off here is a lack of that 4WD ace - superior ride height.

Going seriously off-road is not recommended in the Allroad TDI. There's no low range gearing option (only available with the manual version of the biturbo), the approach, departure and ramp-over angles are poor in comparison to true off-roaders and therefore it is not too hard for the underside to make contact with the ground.

The 225/55 17-inch tyres also proved somewhat suspect, two Goodyear-shod Allroads suffering sidewall blowouts on the same heavily corrugated dirty road within minutes and kilometres of each other during the drive route.

Audi could provide no explanation for the failures, particularly as the Goodyears are specifically developed for the Allroad, along with an identically sized Pirelli. It also exposed a fault for serious off-roading, the spare tyre being a space saver.

Heavy sand also caught the Allroad out, three cars bogging in the same short stretch of track. But lower tyre pressures probably would have avoided this problem.

But it is difficult to envisage too many Allroad owners venturing into territory this challenging. Be it the TDI or the bi-turbo, this is a vehicle destined for chalets and beach houses, not crossing the Tanami desert.

Its car-like behaviour means it is confident on everything from gravel roads to four-lane freeways. It is a testament to how far the diesel engine has come over the past few years. Just wish they could do something about the price.