Jaguar unveils fast, frugal XF Diesel S

Jaguar already has a diesel-powered XF in its Australian ranks, but it will be usurped over the coming months by a new-generation oiler that's quicker, cleaner and more frugal than the existing model.

The new XF Diesel S is powered by the leaping cat's new AJ-V6D Gen III S 3.0-litre turbodiesel engine, which cranks out 202kW and a rippling 600Nm of torque -- compared with outputs of 152kW and 435Nm for the current 2.7-litre unit.

Jaguar quotes a 0-60mph (0-96km/h) split of 5.9 seconds and an electronically governed top whack of 250km/h, which is pretty impressive for a heavy-ish luxo sedan. The real kicker is a claimed overall consumption figure of 5.6L/100km, compared with 7.5L/100km for the existing diesel XF.

Like most latest-gen diesels, the AJ-V6D engine is a clean-burning unit, puffing out just 179g/km of CO2 (versus 199g/km for the outgoing model). Jaguar says the engine also conforms to EU5 emission regulations using "conventional exhaust after-treatment".

The V6 features parallel sequential turbochargers to help generate its power and torque seamlessly, claims Jag, while drive is channelled to the rear wheels via the smooth-shifting six-speed ZF 6HP28 automatic transmission that also features in most of the brand's other models.

For most day-to-day driving, including highway schlepping, a variable-geometry primary turbocharger does all the work, while the smaller, fixed-geometry, secondary turbo is dormant, saving energy and improving efficiency, according to Jaguar.

When the engine revs climb above 2800rpm, the secondary turbo is brought on line within 300 milliseconds, seamlessly boosting the engine output with supposedly no discernible turbo-lag or power-step.

Jaguar engineers allegedly focused on the issue of turbocharger lag at low engine speeds, and the result is that 500Nm of torque is said to be on tap only 500 milliseconds from idle. 

Visual cues that distinguish the XF Diesel S from its siblings include 19-inch alloys, a boot-lid spoiler and discreet 'S' badging.

Jag is also boasting of "significant trim and specification changes -- including many new features", but the press bumf doesn't elaborate on what exactly these are.

The launch of the new diesel will also coincide with the introduction of a luxurious Portfolio derivative as part of the core XF range.