Geneva debut for Porsche 911 GT3 R Hybrid

Porsche CEO Michael Macht only last month said the company would not build hybrid versions of the 911 and Boxster, yet here we are just five weeks down the track and the Zuffenhausen mob has issued the first images and details of a petrol/electric-propelled 911 racer.

The 911 GT3 R Hybrid is derived from the 911 GT3 R revealed late last year, and adds two front-axle-mounted electric motors developing 60kW each to the 353kW 4.0-litre flat-six housed in the Porker's rump.

It seemingly comes as a startling about-face, as Macht last month pooh-poohed the notion of a petrol-electric sportscar, saying: "It's technically possible but it's not part of the plan. It also adds weight."

"We want brake regeneraton and stop-start for our sports cars, but not hybrid. They're not driven in the city, where you get most of the advantages [of a hybrid]."

Macht also voiced his opinion that the performance and safety of lithium-ion batteries was not yet good enough to use them in an electric car or a hybrid.

Presumably, someone at Williams F1 changed his mind and also put to rest any of Macht's concerns about 'batteries'. Porsche sourced the flywheel-based energy storage system for the car from Williams Hybrid Power, the company refining the technology for road-car applications. The system was originally installed on board AT & T Williams cars for F1 racing.

"This is a milestone for both Williams Hybrid Power and Williams F1," said Alex Burns, Chairman of Williams Hybrid Power and Chief Operating Officer of Williams F1.

"Together we have worked to bring this technology forward to the point where it can be tested in a racing car and deployed in a road car. We hope that this will be just the start of the evolution of hybrid systems developed for Formula One moving across to applications where they can contribute to cleaner and more powerful vehicles."

Whatever has gone on behind the scenes to bring this car into the limelight, the 911 GT3 R Hybrid will be unveiled at next month's Geneva motor show, and it makes its competitive debut in the Nürburgring 24-hour race on May 15-16.

However, Porsche points out: "The focus is not on the 911 GT3 R Hybrid winning the race, but rather serving as a spearhead in technology and a 'racing laboratory' providing know-how on the subsequent use of hybrid technology in road-going sports cars."

The racer differs from conventional road-going hybrids in that instead of the usual batteries found in the latter, an electrical flywheel power generator (housed inside the passenger cell, next to the driver) delivers energy to the electric motors.

The flywheel generator itself is an electric motor with its rotor spinning at speeds of up to 40,000 rpm, storing energy mechanically as rotation energy.

The flywheel generator is charged whenever the driver applies the brakes, with the two electric motors reversing their function on the front axle and acting as generators.

Then, whenever necessary, that is when accelerating out of a bend or when overtaking, the driver is able to call up extra energy from the charged flywheel generator, the flywheel being slowed down electromagnetically in the generator mode and thus supplying up to 120kW to the two electric motors at the front from its kinetic energy.

Porsche claims this additional power is available to the driver after each charge process for about 6-8 seconds. Depending on racing conditions, hybrid drive is used in this case not only for extra power, but also to save fuel.

This increases the efficiency and, consequently, the performance of the 911 GT3 R Hybrid, says Porsche, as it reduces the weight of the tank or, alternatively, makes pitstops less frequent.

-- with staff

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