When it was revealed at the 2010 Paris auto show, the Jaguar C-X75 concept was heralded by the company as a revolutionary jet-powered supercar because of its two micro gas-turbine engines that were supposed to generate the electricity for its four electric motors.

The Paris car was no more than a mock-up, though, a concept to celebrate Jaguar’s 75th birthday, and there were no plans for a production version. But when Ratan Tata, chairman of Jaguar Land Rover’s parent company, and Carl-Peter Forster, then chief executive of Tata Motors, saw the reaction to the C-X75’s stunning design, they instructed JLR chief engineer Bob Joyce to find a way to make it. A limited run of road cars was then announced in May 2011, to serve as rolling halos for the Jaguar range.

Out with the Turbines

Tata found the micro turbines interesting enough to take a controlling interest in the company that made them—Bladon Jets—but Joyce concluded that they were not ready for automotive use in general, never mind a $1-million-plus hypercar. But it was agreed that the production C-X75 should be a plug-in hybrid that, like the upcoming Porsche 918, would combine ultra-high performance (targets include a 200-mph top speed, 0 to 60 mph in 3.0 seconds, 0 to 100 in 6.0 seconds) with the possibilities of extreme fuel economy and zero-emissions, full-electric motoring.

Jaguar entered into a partnership with the Williams Formula 1 team to develop the car, retaining the dimensions, shape, and style of the concept. A team of some 75 engineers drawn from both companies has been working on the project for 18 months. This week, as the C-X75 powertrain was being bench-tested, we were given a tantalizing glimpse of the car’s technology and construction.

More Changes

The specific layout of the concept car has changed: The real thing has two axial flux (so pancake-shaped, not cylindrical) electric motors; one drives the front wheels and the other sits alongside an internal-combustion engine at the rear. Lithium-ion battery packs are located just behind the seats on each side of the car, and they flank the gas tank.

All of the electrical components are state-of-the art, the lightest and most compact to deliver the required performance; the prismatic lithium-ion battery cells are the same as those used in the Williams F1 car’s KERS setup. But it is the gasoline engine that is really intriguing.

Four for Fighting

There is no V8 or V12 here: The C-X75 has a lightweight four-cylinder engine displacing just 1.6 liters. This was rumored to be a version of the new Formula 1 engine envisaged by Williams until the FIA changed its mind about future specifications, but turns out to be a fresh design by Jaguar. Like a race engine, it is designed to spin to 10,000 rpm, yet it must also have the capability to be smooth and emissions-compliant at low speeds.

Jaguar has poured a lot into this engine, which is longitudinally mounted immediately behind the cockpit. It has an aluminum block and head, and features dry-sump lubrication. There are two sets of fuel injectors—four in the ports and four direct to the combustion chambers—gear-driven​ camshafts, and variable valve timing. An Eaton supercharger force-feeds air from idle speed and a big Garrett AiResearch turbocharger takes over beyond 5500 rpm; the plumbing to and from two separate intercoolers has electronically controlled throttles. We have heard and seen the engine run up to 9800 rpm on the dyno, wailing like a race car and with the turbo glowing cherry red. (You can hear it for yourself by right-clicking this link and saving the file.)

Jaguar is not ready to release power figures for the car, but says the gasoline engine will produce at least 500 hp. It drives the rear wheels through an automated seven-speed manual transmission, which is more compact and said to be 220 pounds lighter than would be a dual-clutch box. The front motor has a single speed (equivalent to sixth in the main gearbox) and in the Normal driving mode, the power distribution will be 30:70 front to rear.

The driver will be offered four modes—Normal, which will mix and match engine and electric power as in a Prius; EV, which uses only the electric motors for up to 40 miles with a full battery charge; Sport, where the engine will always be running and be supplemented by the motors; and Track, which will operate the same as Sport but mix in chassis and aerodynamic adjustments.

Carbon-Based Life-Form

Using the lessons learned from building its race cars, Williams has designed a chassis and body made almost entirely from carbon fiber. The passenger cell is a monocoque, made from a series of compression-molded panels bonded together, and the rear subframe is also a carbon-fiber structure. Again, Jaguar won’t yet declare any weight figure, saying only that the structure is considerably lighter than the aluminum architecture of any of its existing models.

Compared with the Porsche 918 and the hybridized Ferrari F70/Enzo replacement, the C-X75—which will have a different name by the time goes on sale—takes a smaller-engined, subtly different approach to being, as Bob Joyce puts it, a “supercar with an environmental edge.” As the brand’s most prestigious product, Jaguar can’t afford to get it wrong, which is why it has not yet committed to an on-sale date, a price, or the number to be produced. The best estimates are: early 2014, $1.4 million, and a maximum of 200 cars. We look forward to experiencing at least one of them.

Read more at Car and Driver:

2012 Jaguar XJL Supersport -- Instrumented Test

Seat-Massager Showdown: Rubbers from Audi, Jaguar, and Mercedes Compared - Comparison Tests

2012 Jaguar XKR-S Convertible -- First Drive Review