The master plan. Everyone is at the ready, and there is a keen sense of anticipation. On June 18 and 19,
Team director Andreas Seidl, 40, is a native of Bavaria and a born strategist. His recipe for success consists of farsighted planning. Because he has zero tolerance for unexpected events, he makes sure they virtually never occur. Fritz Enzinger, who heads the LMP1 project at
Together with the four racing engineers—Stephen Mitas, Pascal Zurlinden, Kyle Wilson-Clarke, and Jeromy Moore—Seidl meticulously plans the best possible approach for each race. But after the “opening move” or start of the race, the team shifts into response mode. Endurance races are stories that have a tendency to interrupt themselves. They contain an unlimited number of if/then scenarios, so what each race really boils down to is a constant series of correct decisions in any given situation.
When planning for a race, the first limiting parameter is the distance or range between pit stops. The FIA World Endurance Championship, or WEC for short, stipulates maximum values for both fuel consumption and electric power, which makes it possible to know the maximum range of a car before it has to refuel. The strategists know this information not only for their own vehicles but also for those of the competition. On the 13.6-kilometer circuit of the 24 Hours of Le Mans, the 919 Hybrid will be able in 2016 to complete a maximum of 14.1 laps on a full tank of 62.5 liters. In order to avoid resorting to purely electric power, the car has to refuel at the right time. Yet it shouldn’t return to the pit too early, because the aim is to have the 919 Hybrid arrive at the pit or the finish line on essentially the last drop of gas. That’s because the less fuel the car has in the tank, the faster it can move.
This means there will always be one fueling stop that does not fill up the tank completely. Careful consideration needs to go into when this partial tank makes the most sense. If a race runs without incident, it will be reserved for the end, which is why the final refueling action is often called the “splash and dash.” This can be part of the plan for Bahrain, for example, where weather conditions are stable and neutralization periods are rare thanks to the huge run-out zones, which means driver error rarely leads to an accident. But if Seidl and his team expect rain the morning of Le Mans, then they might plan a partial refueling in conjunction with the stop during which they put on rain tires. Even with meticulous planning, the precise point for this action can only be determined on the spot. And the racing strategy can change in a heartbeat.
Strategy engineer Pascal Zurlinden constantly feeds new information into a simulation program, including data from
Speaking of tires, they are second only to fuel in their significance and complexity for racing strategy. Regarding the crucial question of how long a set of tires will last, expertise from the engineers at racing partner Michelin also comes into play. The main issue here is not when the tires will wear down to the casing, but rather performance curves. The greater the wear on the tires, the slower the lap times for the car. However, this decline in performance must be weighed against the time lost in changing the tires. And it should also be noted that tire wear does not always proceed on a linear basis. Sometimes the rubber hits a low after just a few laps, but then recovers. While this is happening, the car becomes lighter with every lap—which can also have an appreciable effect on how long the tires last.
Seidl has figures on hand: “Our longest distance for a set of tires in Le Mans in 2015 was 54 laps for each car. That means we refueled three times without changing the tires. In their progression from best to worst performance, the tires lost 1.6 seconds per 13.6-kilometer lap.” This figure does not take the fuel conditions into account, of course. “The weight difference of 44 kilos between a full and an empty tank makes a difference of about 2 seconds per lap,” he adds.
What decides the winner in Le Mans? Covering the most distance over the 24 hours of the race. That means driving as fast as possible with as little downtime as possible. For its victorious finish in 2015, the team refueled each of the three prototypes thirty times. Including entry and exit, the fastest refueling stop took 51.3 seconds and the shortest pit stop with tire and driver changes took 1:13.9 minutes. The drivers have to keep going as long as the tires allow, because a stop just to switch drivers would waste valuable time. But how long can a driver keep going without becoming noticeably slower? “All of our drivers can do a fourfold stint of 54 laps during the night in Le Mans,” says Seidl. “They are pros in top-fit condition. But we also have to keep an eye on their times.”
The regulations stipulate both minimum and maximum amounts of time for each driver. For six-hour races, the minimum is 40 minutes and the maximum is 4.5 hours. In Le Mans, each driver has to spend at least 6 hours at the wheel, but may not drive more than 4 out of 6 hours or exceed 14 hours in total. Normally that is not a problem. But what happens if a driver has indigestion? That is an if/then situation that can decide the race. As Seidl explains, “We try to provide the most favorable rest times while also retaining the greatest degree of flexibility right down to the end.” The team director, racing engineers, and drivers discuss who will be at the wheel when. “Here, too, each of our drivers has to be able to handle every racing situation,” says Seidl. “There’s the starting phase, which can often be like a battle and is when you need to keep your cool. There are the long stretches in the night, and of course the honor of driving to the finish. We try to come up with the best-possible deployment and also to be fair to everyone, because the team’s mood has an influence on its performance.”
Whatever story the race ends up telling, diverting, upending, or resuming, the simulation software helps interpret it. At all times, it shows the team what the results will be if the race continues normally and also provides valuable tips on how to deal with unanticipated circumstances.
One example would be whether it makes sense to take an early pit stop if the safety car goes out onto the circuit. The program also calculates the strategic consequences of potential repair stops.
If a car makes physical contact with a competitor, telemetric systems immediately check the tire pressure and aerodynamic data and the driver provides radio feedback. But neither the driver nor the racing engineers on the pit wall can inspect the actual damage while the car is zooming along at 300 km/h. This check is made on monitors behind the scenes, in the “battle room” where Zurlinden sits. Sometimes it is necessary to review the incident in slow motion to determine whether the car must come to the pit.
The pit crew stands ready at all times for a stop on short notice. If that should happen, it’s quite a sensation. At the 24 Hours of Le Mans in 2015, the total time that the three 919 Hybrids spent in the pit lane—including entry and exit—was 95 minutes and 36 seconds. The second-best total time for a team with three cars was a good 130 minutes. Where does this type of advantage come from?
Amiel Lindesay is in charge of the mechanics. “Practice” is the New Zealander’s laconic response when asked what went into this masterful performance. That is an enormous understatement. The choreography for the stops alone is a science. In contrast to Formula One, there are limits to the number of mechanics who are permitted to work on the car during the stops—and the fewer there are, the harder it is. The 2016 regulations are even stricter—the details fill eleven pages. They stipulate, for example, that only two people can do the refueling, that the car has to stand on four wheels during that procedure, that the tires may only be changed when the fueling is over, that no more than four mechanics and one impact wrench may be in action on the car at any time, and much more—including the catalog of penalties.
Lindesay works out when to take each step and perform each action and also determines who should do each job. Then dry runs are held at the workshop. More than 250 stops are practiced just at the workshop every season. Plus all of the stops during test-drives on the racetracks, and of course during the races themselves. One wheel with a tire weighs 19.9 kilos. The mechanics have to be strong, agile, and fit. They also have to withstand an enormous amount of psychological pressure. The team is prepared, awaiting the action. And team director Seidl is watching over all of it and planning the next move in the chess marathon for the world championship title.
By Heike Hientzsch
Photos by Markus Bolsinger
Different classes of cars enter World Endurance Championship (WEC) races at the same time. Under normal conditions, the only ones with a chance to win the overall victory are the LMP1 cars (Le Mans prototypes, Class 1), which include the
The cars in the LMP classes are prototypes that are not based on production cars. Their design only has to comply with the technical regulations. The LMP2 category also allows for open racing cars (no top). By contrast, cars in the GT classes have to be based on road-going production cars, although the regulations also allow for extensive modifications.
The race in Le Mans runs for 24 hours, while the other WEC contests are 6 hours long. The winner is the car that covers the farthest distance (i. e., the greatest number of laps) by the end of the prescribed time.
The qualifying, which is run jointly for LMP1 and LMP2 cars, lasts 20 minutes. Each car has two drivers, and the qualifying time is the average of the best lap time for each. Each driver can use a fresh set of tires.
In order to limit costs, no more than five new engines can be used per vehicle during the season. This regulation also prohibits any track-specific engine developments.
In the event of an accident or other disturbance on the track during the race, the WEC uses “full course yellow” periods as an alternative to safety cars. When ordered to do so by the race directors, all drivers have to slow down to 80 km/h and maintain their distance from the car in front.
For the 6-hour contests, including the qualifying and the race itself, 24 dry-weather tires are allowed per car. For Bahrain and Shanghai, the number is 32. There is no limit to the number of rain tires or intermediates allowed.
The point system is the same as that used in Formula One and awards the first ten finishers: 25, 18, 15, 12, 10, 8, 6, 4, 2, 1. In Le Mans the point total is doubled, and for all races an additional point is awarded for the pole position.