"Something spectacular" was what Porsche promised to reveal upon their return to the Detroit Auto Show after two years of absence. The company did not oversell. Its new car, the Porsche 918 RSR is spectacular, but it's also an interesting proposition. Rather than just tack a coupe top onto their 918 concept car, they've gone and made it into a racing laboratory, complete with the company's remarkable flywheel accumulator hybrid system riding shotgun in the passenger seat.
Stylistically, the 918 RSR is part Cayman, part Carerra GT and part homage to the monstrous 917 race cars of the past. The low-slung super car concept blends all those shapes into something familiar but new at the same time. Its bulging fenders flow together with precisely placed cooling and venting ducts punctuating the carbon-fiber shell. Side exit exhausts, downforce canards, a high-mounted rear spoiler and a deck-mounted cooling fan call back to the Le Mans-dominating 917's.
That svelte skin hides a tour de force of cutting edge technologies. It starts with an all-carbon-fiber chassis into which is a massaged version of the direct-injected V8 from the RS Spyder developing 563 hp at a shrill 10,300 rpm. The engine drives the rear wheels via a six-speed, paddle-shifted transmission with straight cut racing gears. That screaming V8 is augmented by torque-vectoring two electric motors fitted to the front wheels each adding 100 hp at the bottom end of the rev range; Peak output for the system is a stout 767 hp.
For this racing lab, the high-tech luxury of the original 918 Concept has been stripped away. Toggle switches, momentary buttons and kill switches replace nav screens and styled buttons. Situated where the passenger might normally sit, is the flywheel accumulator, a vertical-axis electric motor designed to store energy in the form of inertia. As the car brakes, the front wheel motors reverse polarity and convert the car's momentum into electricity which is used to spool up the flywheel. When it reaches a maximum speed of 36,000 rpm, the driver may push a button which reverses the flow of energy, sending a burst of 200 hp to the front wheels for up to 8 seconds. Stunning stuff.
The use of the accumulator rather than the battery pack that provided power storage on the old 918 Concept indicates Porsche's growing confidence in their unique and race-tested flywheel system. In addition to efficient storage and transfer of energy, it saves a considerable amount of weight over even a lithium-ion battery. At the moment, Porsche has made no official announcement to campaign the car in any kind of sanctioned racing, or for that matter a street car. But the tech is already in use on its 911 hybrid racer. Usually, when we hear this much noise about a technology, the new hardware eventually dies make it onto production cars. We'll have to wait however, at least another two years.
