Drivers are constantly keeping an eye on the lap times while in the car – aiming to hit their mark and stay consistent. But for this year’s FIA World Endurance Championship, teams and drivers will have new numbers to keep an eye on.

When in the car, drivers will have to keep an eye on the maximum amount of energy per lap generated by the hybrid system and also the amount of fuel used per lap.

Only a limited amount of energy per lap may be fed into the car’s powertrain through the hybrid system – 2, 4, 6 or 8 megajoules per lap at Le Mans, depending on the class. If these limits are exceeded, 10, 40 or even 60-second stop-and-go penalties threaten in the case of repeated violations. The same penalties apply if the permissible amount of fuel per lap is repeatedly exceeded. Likewise, the fuel flow rate and the engine’s boost pressure are checked.

“For drivers and engineers, it’s crucial to understand the complexity of the new rules and to apply this knowledge to racing situations in an optimum manner,” explains Leena Gade, who as a race engineer for Audi won the Le Mans 24 Hours in 2011 and 2012.

“This requires a flawless information flow. We’ve got to keep the drivers informed of whether they’re staying within these limits over the radio.”

The Audi Sport squad has successfully been testing this. If a driver is slowed by a vehicle heading into a turn, it may be advantageous to initially follow this car to save fuel and to only overtake it exiting the corner. But approaching a turn more gently also has effects on the car’s handling. “The drivers are no longer putting the tires and suspension under load as systematically as before,” says  Gade based on her observations.

To Audi factory driver Lucas di Grassi, who was involved in the tests of the new car at an early stage, the new task poses an intriguing challenge.

“It doesn’t seem like I’d have to fundamentally change my driving style now,” said di Grassi.

“Even in the past there were situations in which we had to watch our fuel consumption in order to put certain race strategies on track. Now we’re driving as fast as possible without ever losing sight of the set consumption limit. And if we do exceed the limit once, then we’ve got two laps to compensate for the excess by reducing our consumption. So here’s another challenge being added to our task list which means we’ve got to be both efficient and fast.”