One of the stars of the Geneva, where I’m going tomorrow, will be an hybrid car. Nothing new here, but wait, this is not about a new contender for the Prius, it’s a racecar.

We’ve had performance hybrids before. I still remember fondly my test drive of the Lexus GS450h. But that new Porsche has no intent to be a fast road car, it’s a pure racecar, courtesy of Porsche Intelligent Performance. The base is the Porsche 911 GT3 R, a car you can’t get registered for road use. Its engine revs happily at more than 8000 rpm, but as a race engine, it’s a very poor performer at low engine speeds.

Now think about an hybrid such as the Prius which is very long-geared, counting on its electric motor to give quick response while the gas engine keeps running at low revs, where it is the most efficient, but you just couldn’t do that in a Porsche 911 GT3 R.

You also have to wonder about the effectiveness of an hybrid system like the Hybrid Synergy Drive from Toyota, in race conditions. Would it be quick enough? I know Toyota’s system is impressive, when you look at the dashboard display on a Prius, with the motor switching from regen to assist and back in seconds. But are the energy flows fast enough for racing?

Racecars accelerate hard, and brake even harder. This is one of the reasons that made Porsche choose a flywheel instead of a battery to store energy. Flywheels are mechanical. They’re disks spinning at very high speed. You give them energy by making them spin faster, you take their energy by reducing their speed.

This flywheel can spin at speeds of up to 40,000 rpm, ands its great advantage is that it can transmit its power shockingly fast. It can supply up to 120 kw! A battery which could supply the same current would be at least 3 times heavier.

Hey! That’s Porsche. With decades of engineering excellence behind them, they knwo a thing or two about making cars fast…