Holden working on V12

General Motors product czar Bob Lutz has let slip that Cadillac -- GM's American flagship brand -- is honing a new top-end model that will rival the Mercedes-Benz S-Class in the premium end of the luxury car segment.

Lutz made the statement at the opening of a Hummer dealership in the UK last week. He has been quoted as saying the new Cadillac will be unlike anything the marque has offered before. He has also confirmed Holden engineers are working on the engine that will power the fleet-topping Caddy.

Indeed, reports suggest the car will use Holden Commodore V6 engines as its source of propulsion. Well, in a manner of speaking… The uber-Caddy will actually be powered by a brand-new V12, yielded by 'mating' two 3.6-litre Alloytec V6s on a single crankshaft -- a layout that will enable production to be carried out on existing lines.

Adding to the car's high-tech credentials, the engine will be equipped with fuel-saving displacement-on-demand cylinder shutdown (a system that GM already offers in its V8-powered US SUVs and that Holden is due to debut Down Under), advanced exhaust catalysts and exhaust gas recirculation to cut emissions, as well as direct fuel-injection.

Well-placed sources suggest the V12 will punch out about 450kW and 700Nm, putting it in the right ballpark to lock horns with range-topping versions of the S-Class.

It's believed the car will derive its styling inspiration from Cadillac's stunning Sixteen concept (pictured), which was so named because its mile-long bonnet concealed a V16 engine. However, Cadillac's boffins have obviously decided that 12 pots are enough for the production variant.

Adding to interest levels is Bob Lutz's comment that the Cadillac -- dubbed XLS by pundits -- will be offered as a global flagship model, rather than just a US-only proposition. Lutz reportedly sees the XLS as being the ideal weapon with which to build Cadillac's brand identity internationally.

The car is tipped to make its public debut in 2009 (possibly in that year's instalment of the Detroit show), before going on sale later that year or in early 2010.

Although unconfirmed, US reports are strongly pointing at the XLS being built on a stretched version of the Zeta rear-wheel-drive underpinnings used by the Holden Commodore and upcoming Chevrolet Camaro.

Much of the development work for the XLS will be carried out locally by Holden's engineers and prototypes of the engine are rumoured to be already running in long-wheelbase Holden 'mules'. Coincidentally, Holden sources have confirmed that the two-door Camaro is now also running in mule form on Australian roads.

Holden boss Denny Mooney has gone on the record on numerous occasions with his desire to introduce the Cadillac brand in Oz, so it's distinctly possible we'll see the XLS here in due course.

-- with staff