FIA WEC Prologue at Circuit Paul Ricard, Le Castellet, Provence-Alpes-Cote-d'Azur, France, on March 28 2014. (Photo: FIA WEC)

Prologue at Circuit Paul Ricard, Le Castellet, Provence-Alpes-Cote-d’Azur, France, on March 28 2014. (Photo: )

A new era of sports car racing begins this weekend at Silverstone, as the ACO’s much-anticipated 2014 LMP1 regulations debut in the FIA World Endurance Championship.

The game-changing set of technical rules sees the premier prototype class now not only measured by speed, but also efficiency, with each car limited to a specified fuel allocation. It marks as much as a 30 percent reduction in consumption from last year.

Additionally, the Audi, Toyota and Porsche squads are equipped with cutting-edge hybrid systems, which have become mandatory for all factory LMP1 teams, and at a significant increase in energy capacity and release from previous years.

“All of us are anxious because are entering a new era,” said ACO Sporting Director Vincent Beaumesnil. “As we’ve said before, it’s not an evolution but a revolution of what we’re doing.

“The cars have been on track, the teams are ready and despite the huge amount of work they had to do in the winter, we can already see the performance of the cars is what we expected.”

While the prototypes from Audi and Toyota may have a similar appearance from last year’s models, both the R18 e-tron quattro and TS040 Hybrid are all-new, along with Porsche’s 919 Hybrid.

The regulations call for a weight reduction of 30 kg, a 10 cm narrower car, smaller 14-inch wide tires as well as a larger greenhouse area and revised driving position for improved driver visibility.

In terms of powertrains, each manufacturer has gone for a significantly different approach.

Porsche, making its return to the 24 Hours of Le Mans with a factory prototype for the first time in 16 years, has opted for a gasoline-powered 2.0-liter V4 turbo engine, combined with a Formula One-like KERS unit on the front axle and an exhaust gas recovery system on the rear.

The 919 Hybrid will run with a maximum of 6 megajoules of hybrid capacity per lap of Le Mans.

Toyota has also gone with a dual hybrid system, but with two electric motors that are mounted on both the front and rear axles and supercapacitors storing the energy.

The TS040 Hybrid utilizes a 3.7-liter normally aspirated V8 gasoline-powered engine, marking a 0.3 liter increase in displacement from last year. Like Porsche, Toyota will run in the 6 MJ energy sub-class.

Two-time and defending FIA WEC champions Audi, on the other hand, has opted for the lowest sub-class of 2 MJ with its diesel-powered R18 e-tron quattro, which also features a larger 4.0-liter V6 turbo powerplant but with only a single, flywheel-driven hybrid system powering the front axle.

Audi’s approach of running with the minimum amount of hybrid capacity offers the reward of having the possibility of more fuel flow per lap compared to the Toyota and Porsches, but effectively at the same fuel tank capacity as the competition.

The fuel flow meter is at the heart of the new regulations. Each LMP1 car is equipped with two meters, one as a backup, in order to regulate the allocated fuel flow per lap.

As an added twist, cars that exceed their allocated fuel consumption by more than 2 percent over a three-lap consecutive average will be given stop-and-hold penalties ranging in severity.

The FIA will rely on an automated system to monitor each car’s fuel consumption and hybrid energy usage in real time. Teams, meanwhile, will have the same information available to them so they can correct any overconsumption issues to avoid penalties.

Despite some early concerns over the races turning into economy runs, the FIA and ACO insist that won’t necessarily be the case.

“What we wanted to avoid was the type of racing that was in the past,” said FIA Technical Director Bernard Niclot. “[Previously], we had defined the quantity of fuel for the race.

“Then, depending on the weather conditions and the number of laps behind a safety car, some competitors were able to save fuel that could be used [later].

“We didn’t want to enter into this type of racing. We want, in that each lap, the driver has the same quantity to consume. This is why we’ve introduced this regulation with [a] quantity of fuel per lap.”

Beaumesnill added: “For the drivers, there’s still a ‘full attack’ driving style. They are not in economy runs. This is why we made the lap-by-lap rule.

“In the end, for sure… they have to develop a new type of driving. But in the end, dealing with the energy is a way for them to make a better lap time. It’s always the idea to be faster.”

It’s a step into the unknown for drivers and teams. Thousands of miles of testing, including endurance simulations have been run, but largely without the competition on track simultaneously and running to the same programs.

That’s why Sunday’s Six Hours of Silverstone is shaping up to be one of the most unpredictable races yet, in what’s only the first chapter in the LMP1 revolution.