Large, luxurious cars used to have large, luxurious engines. Their smoothness and quietness suited the image, and if you could afford such a car you wouldn't worry about the petrol costs. But times have changed, fuel costs more, and Europe has fallen in love with the diesel engine. That was the breakthrough: to make diesels smooth, quiet and powerful enough to move an S-class Mercedes-Benz or a 7-series BMW in the style to which it is accustomed. Today's turbodiesels zoom along in style often matching, or even surpassing, same-size petrol engines for power and far exceeding them for relaxed pulling ability. BMW, Mercedes-Benz, Audi, they're all at it.
And Jaguar? Well, Jaguar came late to diesel, first with the compact X-type and then with the excellent, if odd-looking, S-type. These two cars alone have meant that even in Jaguar's British home market, where diesel fuel lacks the price advantage of other European countries, the company now sells more diesel cars than petrol ones. But despite this fact, the large XJ-series, Britain's best-selling luxury car, was without diesel power - until now.
Meet the Jaguar XJ TDVi. It uses the same 2.7-litre twin-turbo V6 engine as the S-type diesel, but the XJ TDVi has a secret weapon: its bodyshell and structure are made of lightweight aluminium. So it actually weighs less than an S-type, making it both faster and more economical. In fact no other luxury diesel has an engine as small or uses as little fuel. Yet its performance is fully competitive. It reaches 100km/h in 8.2 seconds, has a maximum speed of 227km/h while and emits a modest 214g/km of CO2.
It still seems hard, though, to reconcile a diesel engine with a Jaguar, the epitome of silky smoothness. But if you stand outside the XJ TDVi when it's idling you can barely discern the unfamiliar nature of the engine. There's just a metallic edge to an otherwise typical V6 hum. How does Jaguar do it? With highly sound-absorbent foam under the hood and an airtight seal between the hood and engine bay. Inside, the bulkhead between engine and driver is double-skinned, and all the glass is laminated with an acoustically-absorbent interlayer. The key, though, is the "active" control of the engine mountings, a first in Europe.
The XJ TDVi is a driver's delight. It pulls strongly across its speed range and is perfectly suited to the six-speed automatic transmission. Also, being light, it feels very agile. That even applies to the Sport Premium version, despite its firmer springs and wider, lower-profile tyres. Which is good news, because this model frees the whole XJ-series from its sepia-tinted past.
It's all very well creating a car with an obvious brand identity, but in the XJ's case it was as if Jaguar had run out of ideas. Part of the problem was the excess of detail and the sacred wood-and-leather interior. But the Sport Premium gets rid of both problems and suddenly finds its identity as a Jaguar for the modern age.
The whole XJ range has now lost the side strakes and finishers around the windscreen and rear window. The Sport Premium also lacks excess exterior chromework, while inside we find - deep breath, this is a Jaguar we're talking about - embossed aluminium. So a Jaguar XJ6 with a terrific turbodiesel engine and no wood is the best new Jaguar you can buy today. How times change.
JAGUAR XJ6 TDVI
Price from €64,000
Engine twin-turbo diesel, 2,722cc, V6 cylinders, 24 valves, 207bhp
Transmission six-speed automatic gearbox, rear-wheel drive
Performance 141mph/225kmph, 0-62mph/0-100kmph in 8.2 seconds
Fuel consumption 35.0mpg/8.1 litres per 100km
Words John Simister