AUDI A4 Cabriolet TDI: You are about to read a somewhat historic road test. Who could have believed that cabriolets, the stuff of automotive fashion, would come in diesel form? Audi here is the pioneer with its A4 cabriolet and when we did our topless driving in the balmy summer-like days that preceded Easter, the news was greeted with incredulity.
Actually, most of the car's many admirers didn't seem to know or notice: they had to be told. Even the start-up isn't tell-tale any more.
Driving the 2.5TDI turbodiesel is virtually indistinguishable from a petrol unit. There's no vibration, no black smoke and very little noise. It's so easy to forget that word diesel.
The historic thing pertains only to right-hand-drive A4 cabriolets: the previous model was available as a drop-top oil burner, accounting for a sizeable one-fifth of all sales. The success of that model was a key in persuading Audi bosses to do right-hand-drive availability, particularly as the British market is Europe's biggest for convertibles. Here in Ireland they have become popular too, symbolic more of our affluence than any changing weather pattern.
At the heart of the A4 cabriolet TDI is a V6 2.5-litre unit developing 163 bhp at 4,000 rpm. With a top speed of 135 mph, it's certainly no slouch. More importantly, it gets from zero to 60 mph in just over 10 seconds.
Using kickdown in the smooth Multitronic CVT gearbox should mean useful and nimble acceleration. Examples are 3.9 seconds from 30 to 50 mph in third, 5.1 seconds from 40 to 60 mph in fourth and 6.4 seconds from 50 to 70 mph in fifth. The in-gear flexibility of the CVT's manual shift function is every bit as effective as a conventional manual box.
In fact, this TDI engine isn't new. It dates back five years and has been modified twice, first going from 150 to 155 bhp and now to 163 bhp. This engine isn't totally with it either, for it doesn't employ common-rail technology, buzz words for thoroughly modern diesels these days. As we have said though, it's no embarrassment, far from it.
One observant fellow did notice the TDI badge on the rear. Was it really true, he asked. Yes, it was and he couldn't believe that such an elegant machine could be powered by tractor fuel.
Coachwork specialist Karmann has produced a beautifully balanced shape that combines influences of another Audi sibling, the TT, with the A4's chunky body. The detailing is superb and the build quality unbeatable.
Not surprisingly, the roof is no afterthought. The triple layer canopy is virtually ridge-free and has a glass rear screen with integral heating elements to aid visibility. With the hood up, the cabriolet has a remarkably low drag factor at 0.30Cd.
Dropping the top is done using just one finger on a button. Topless, the shape loses none of its drama - if anything it looks even better.
When you fancy wind in the hair, the hood folds itself into a compartment in the boot. With the roof up, this holder can be stowed away to free up an additional 69 litres of load space.
Inside, the TT's influence is obvious in the oval air vents and chrome-ringed dials. The cabin is an attractive and opulent environment and the widespread use of quality materials makes a visual impact.
We were particularly impressed by the optional dark blue pearl nappa leather that was fitted on the test car. That's a €2,855 option, boosting the €58,160 ex-works starting price.
The bonus of driving a diesel is, of course, economy and, with an overall return of 38.2mpg for a diet of mostly long drives, we were reasonably rewarded. The official mpg figures for the record are 30 urban, 47 extra urban and 39.2 combined.
With the tank taking 70 litres, the 2.5 TDI cabriolet is a very long-legged proposition. You should be able to go from the far north of Ireland to the far south, with fuel to spare.
Potential A4 cabriolet buyers have a choice to make - to go for the ground-breaking diesel or stay with the petrol engine. Naturally, it's a decision that can be influenced by price.
Compared with the 2.4 petrol version which develops 170 bhp and also comes fitted with the Multitronic gearbox, the diesel premium is modest enough, at €2,800. You can also go for the 2.5TDI with the normal manual gearbox: choosing Multitronic is a €2,820 premium.
Some other points worth mentioning: despite the diesel's economy credentials, it's 100 kg heavier. It's not only the engine which accounts for the weight gain: additional soundproofing makes a contribution.
Audi claims that the A4 cabriolet is a four-seater. Somehow though, we couldn't imagine two adults enduring the back seat for long. It's really only for short runs.
Price apart, why buy the cabriolet TDI? It should be less expensive to insure and there are longer service intervals. It has low CO2 emissions, useful if we get a green tax, and over three years it should depreciate less than its petrol version.
According to John Hayes, Audi's sales manager here, about a dozen people have opted for the diesel out of total A4 cabriolet registrations of 40. "But we expect the ratio to grow with diesel having such an assured future," he says.
So, it looks as if Audi's bold step will pay off. Glamorous drop-top wind-in-the-hair motoring will never be the same, now that the diesel is such a seriously tempting alternative. As of now the A4 cabrio TDI has the field to itself but that surely must change.
Is there a BMW 330d cabriolet coming - and perhaps a diesel drop-top version of the new Saab 9-3? Watch these spaces.