Green Car Centre
Audi A8 4.2 TDI quattro
Introduction
Burning diesel is not the answer to the planet's problems, but there's no denying that the latest generation of oil burners have significant advantages over their petrol-fuelled alternatives in terms of fuel economy and emissions of greenhouse gases. When the diesel engine in question is a 4.2-litre V8 with well over 300bhp and the car is a super luxury saloon, there seems to be no argument against.
What is it?
The Audi A8 itself is one of the most understated luxury saloons on the road, eschewing the avant-garde lines of its rivals, the BMW 7 Series and Mercedes-Benz S-Class in return for subtly muscular curves and detailing shared with the rest of the Audi range. It's every bit as good though and the 4.2 TDI quattro version is unique in that it offers a V8 turbodiesel engine with full-time four-wheel drive.
It may sound rich to define a 4.2-litre V8 as 'green', but in comparison to petrol powered alternatives it does use less fuel and emit less carbon dioxide. Combined consumption for instance, is claimed to be 30.1mpg, while CO2 emissions are rated at 249g/km. Audi's own petrol 4.2-litre V8 isn't too far away from those figures, thanks to direct injection, but it can't touch the diesel's torque figure of 650Nm, which is available from as low as 1,600rpm.
How does it drive?
That torque figure dominates the experience, as it means there's no reason to rev the engine to make decent progress. Instead, better to waft along with barely a whisper from the engine. Road and wind noise are also well suppressed, which add up to a serene driving experience.
Audi doesn't make any claim to endowing the A8 with dynamics to endear it to the keen driver, and nor is it as interesting to steer down a fun road as its rivals, but in return the A8 is massively comfortable and its four-wheel drive ensures that all of the engine's torque is put down in a fuss free manner, regardless of the conditions.
Planet hugger or planet mugger?
To answer this question, we need to look at other cars that the buyer of the A8 4.2 TDI may consider. BMW's 730d produces less carbon dioxide and uses a little less fuel, but can't touch the performance of the Audi's V8. It's the same story with Mercedes-Benz's S-Class CDI. So if you want to hug the planet that little bit more, those are the cars to go for, but if you're as interested in performance, then the Audi offers an alternative to the petrol models.
Verdict
The 4.2 TDI A8 is likely to be bought as much for its formidable torque output as it is for its fuel economy. It certainly betters similar performing petrol models in terms of 'greenness', but it can't really lay claim to being a green car per se.
Shane O' Donoghue
Tuesday February 12
Photos
Carbon calculator
-
Top questions from Yahoo! Answers
Got a question? Get the answer at Yahoo! Answers
-
Top photos from Flickr
