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Porsche 918 RSR Pushes The Hybrid Envelope

| Senior Writer, RacinToday.com Saturday, January 15 2011

The new Porsche 918 RSR is a supercar wrapped in a dilemma for the folks in Stuttgart. It's all dressed up with nowhere to race. Yet.

By Jonathan Ingram | Senior Writer

When Porsche introduced its 918 Spyder at the Geneva Motor Show in the spring of 2010, the  supercar represented a new wave of performance plus efficiency due to its hybrid power from a lithium-ion battery. At a top speed of 199 mph delivered from a car capable of 78 miles per gallon, the 918 Spyder raised more than a few eyebrows as well as the standards for thinking green.

This week, the Stuttgart company introduced the racing version of its latest supercar at the Detroit International Auto Show. The Porsche 918 RSR has raised a lot of question marks if only because the car has a number emblazoned on the side and a purposeful rear wing adopted from the RS Spyder prototype – but no place to race.


The 918 RSR does not use any battery power. Instead, it is fitted with the front axle system and a flywheel accumulator that produces and retains regenerative energy from braking, a system raced last season by the 911 GT3 R Hybrid. The Porsche 918 RSR similarly fits no known set of racing rules. According to informed sources at Porsche, the new 918 RSR was kept a closely held secret. No effort was made by the company prior to the launch in Detroit to inform decision-makers in the sport about the fact a new race-ready supercar from Stuttgart, including a stripped down interior, was ready to roll.

It’s a surprise somewhat along the lines of the year Porsche introduced its potent 917 to the racing world by lining up 25 of them outside the factory at Zuffenhausen in 1969 before anybody knew the company was planning to homologate a new vanguard for the endurance racing wars. In the case of the 917, the company was committed to complying with existing homologation rules and to catching the opposition off guard. In this case, there are no clear cut rules for racing hybrids and therefore there are no competitors to catch off guard at present.

With a paint scheme highlighted by the orange taken from the power cables under the front

The cockpit of the 918 RSR.

cowling, Porsche seems to be trying to stake out a future for racing hybrids on terms that include a rule book drawn up by equating the amount of energy each entrant can produce. In the case of the 918 RSR, that means 563 horsepower at the rear wheels from the mid-mounted V-8 taken from the RS Spyder, plus 150 kilowatts of electrical thrust from the two motors mounted on the front axles that work as generators under braking. According to Porsche, that means a maximum total of 767 horsepower.

The wording in its media release underscores Porsche’s desire to race the 918 RSR, although nothing about actually putting the car on the track has been said. “With the new 918 RSR racing laboratory,” the release reads, “Porsche is now elevating this motor racing hybrid concept to an experimental level. In the 918 RSR, ‘Porsche Intelligent Performance’ equates to research into methods for further sustainable efficiency improvement under the intensified conditions of the race track, lap times, pit stops and reliability – a metier in which Porsche has been demonstrating its success for over 60 years.”

It may take some time for sanctioning bodies to digest this news, although it was not much more than a month after the GT3 R Hybrid’s introduction in Geneva last year until it was racing at the Nurburgring with ADAC (Germany’s largest automobile club) in the VLN series as a warm-up for the track’s famed 24-hour. Because of a starting field for the 24-hour approaching 200 cars on the 22-kilometer Nordschleife circuit and its vast array of classes, the Nurburgring classic is the most likely spot for the 918 RSR to first turn its wheels in competitive anger.

Although the American Le Mans Series welcomed the GT3 R Hybrid last year as an unclassified vehicle at its Petit Le Mans in October, it’s highly unlikely a new car designed for long distance events would be approved to appear at the Mobile 1 Twelve Hours of Sebring in March. What if the new production-based car gave the prototypes of Audi, Aston Martin and Peugeot a hard time due to superior fuel mileage and the ability of a driver to utilize 150 kilowatts of power to the front wheels on command?

The organizer of the 24 Hours of Le Mans, the Automobile Club de l’Ouest, has one invitational slot available at its discretion for the great endurance event each June, a relatively easy place to introduce an unclassified car. But with its combination of the direct injection V-8

Porsche 911 hybrid from 2010. (Photo courtesy of the American Le Mans Series)

from the giant-killing RS Spyder and the all-wheel drive created by the electric motors on the front axles, the new Porsche could present some political problems. Audi’s chain of command, for one, vividly remembers having its diesel R10 thrashed by the RS Spyder in the ALMS in 2007 when the rules were adjusted to equate the larger LMP1 and smaller LMP2 prototypes.

In addition to the Petit Le Mans, the Porsche GT3 R Hybrid also competed in China at the final round of the inaugural Intercontinental Le Mans Cup. This new and very ambitious endurance racing series controlled by the rule makers at Le Mans would like to make a big splash in the coming year. So perhaps the 918 RSR might well find a place as an unclassified competitor in the ILMC, which includes Sebring and the Petit Le Mans in this year’s seven-race schedule.

The ACO, in fact, is likely to continue supporting the development of hybrids while continuing to dither on how to come up with a set of rules and also address the issue of electrically charged cars crashing during the course of races. Perhaps it will be the GT3 R Hybrid that gets the nod as an unclassified car at Le Mans, because it is a known quantity. On the other hand, the hybrid system for the 918 RSR is precisely the same.

There can be unforeseen risks when it comes to a “racing laboratory” for manufacturers as well as corner workers and medical safety personnel. At last year’s Petit Le Mans, the prospect of seeing how well the GT3 R Hybrid equated to its competitors was lost when an unexpected front tire problem developed. It was not until the race began that Porsche and Michelin realized the heavy loading at the front axles caused a problem with the compound and tire used during testing at the high-speed Road Atlanta circuit. Testing is one thing, racing in traffic is another.

From Porsche’s perspective, that’s what the racing is all about – putting its equipment to the maximum test in an environment that can’t be matched otherwise. The company has proven time and again that road car development is maximized by race car development. The key road car question: the RSR raises the prospect that Porsche may eventually produce a road car with a flywheel for storing energy in place of, or in addition to, using a battery. (For the racing application, the flywheel occupies the space of the nominal front passenger.)

All of this, of course, brings up another thorny problem, not to mention an age-old debate. At a time when the Le Mans organizers are fully committed to prototypes, the 918 RSR is clearly a road going GT car and could rekindle the debate about just what type of vehicles should be winning the world’s most important endurance race?

The new Abruzzi from Panoz Motor Sports, for example, was originally designed to compete with the prototypes for the over-all win at Le Mans. That idea eventually was nixed by the ACO’s hierarchy, resulting in a road-going Abruzzi equivalent to the current GT class, which is considerably slower than the prototypes.

The rules for racing hybrids cannot be far off. Audi’s V-6 turbo diesel in the new R18 prototype has a smaller engine not only due to new regulations curtailing displacement. The company decided against a V-8 in part with an eye cast on saving space and weight for the additional equipment required with a hybrid. (In prototype form, hybrids have thus far utilized the rear brakes as the regenerative source.) Archrival Peugeot has long since displayed a hybrid prototype, although the successor to the company’s 908 is believed to have a V-8 turbo diesel. Honda’s new customer V-8 twin turbo could become a V-6 in short order, according to insiders, to accommodate a hybrid approach.

For now, the rule makers continue to fiddle with how to equate regenerative power with traditional internal combustion fuels and engines. If nothing else, Porsche is pushing that process by demonstrating yet again a commitment to racing hybrid vehicles.

– Jonathan Ingram can be reached at jingram@racintoday.com

| Senior Writer, RacinToday.com Saturday, January 15 2011
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