Jaguar XF 3.0 Diesel S (2010) CAR review

Is Jaguar at a stroke about to answer our biggest criticisms of the XF executive saloon? Now the dust has settled after the epoch-bending new four-door replaced the stuffy S-type in 2008, we've grown used to seeing the wedgy new Jag on our roads and had time to assimilate the XF's place in execville.

CAR Magazine didn't swallow the PR spin and placed the XF behind its BMW 5-series nemesis when we group-tested the XF against its rivals, including the Mercedes CLS and Lexus GS. Our biggest criticism? The XF's weedy 2.7-litre V6 diesel engine, which was nonchalantly dispatched by the BMW 5-series' cleaner, brawnier, more efficient diesel engines. It's a failing confirmed by life with our long-term test XF 2.7 D.

Cue the new family of expanded 3.0-litre twin-turbo diesels arriving in the XF in March 2009 (alongside the new naturally aspirated 5.0 V8 and supercharged XFR). These are important new engines – bound for action in the new 2010 Jaguar XJ, XK sports car, XF, Land Rover Discovery and numerous Range Rovers. It's an unusually swift engine overhaul for the XF, a car that's only been on sale for 12 months...

The new Jaguar XF Diesel S: should the BMW 535d be worried?

Well spotted. The higher-powered XF Diesel S is firmly targeted at the BMW 535d. The old 204bhp 2.7 TD has swollen to 3.0 litres in capacity and now comes in two power outputs: 237bhp and 271bhp.

Jag's not let any journos loose in the lower-powered XF diesel yet, so we're only able to report on the range-topping Diesel S. It's a sign of the times that Jaguar launched its first derv model back in 2003 and here we are – just six years later – with a full, Boxster-baiting performance oil-burner.

Hang on a minute. You mentioned the Boxster?

Artistic licence? Hardly. The Jaguar XF Diesel S is claimed to hit 60mph in 5.9 seconds, within a tenth of Stuttgart's new roadster. And the new V6 has a whopping 600Nm, that's 443lb ft, of torque from just 2000rpm. Jag says 369lb ft of that twist is on tap within 500 milliseconds of idle. Impressive stuff, on paper at least...

The new V6 employs parallel sequential twin turbocharging: most of the time, a variable geometry turbocharger does all the work, leaving the secondary turbo dormant. But when the revs hit 2800rpm, this smaller, fixed-geometry blower kicks in to provide additional puff.

It's different from other twin-turbo systems that use a smaller turbo for low revs and a larger secondary blower for the big work – and Jag claims its system, which isolates the smaller turbo from exhaust gases until needed, reduces pumping losses, consumption and CO2. Also helping the headline figures is a new, third-gen common-rail system using piezo injectors operating at 2000 bar for more precise fuel measurement.

>> Click 'Next' for our verdict on the new Jaguar XF Diesel S