Fuji 6 hours - Analysed

Truswell Gives the Japan WEC Race the Treatment

The 32,000 spectators who witnessed the six hour World Endurance Championship race at Fuji were indeed treated to a spectacular race. Inevitably, in a race of this nature, it was enlivened by some great battles for class honours, particularly in LMP2, but it was the fight for the overall lead of the race that caught the attention as the two Audi R18 e-tron quattros raced tooth and nail against the singleton Toyota TS030 Hybrid.

The Toyota’s win was well-deserved and hugely popular, but everyone at Audi must know that this was a race that they could have, and should have, won.

There was some evidence before the race that the Audis would struggle to run their tyres for two stints on the super-smooth Fuji raceway and so it proved to be. What was not clear was whether the Toyota would be able to achieve the required lap times if they double-stinted their tyres. But such a strategy would mean significantly less time in the pits for Toyota, making it a very attractive proposition. As the race unfolded, it seemed that the tyres were deteriorating on the Toyota during the second stint and that the lap times were suffering as a result. But Kazuki Nakajima’s two and three quarter hour drive in the second half of the race was the stuff of which legends are made and played a significant part in Toyota’s ultimate victory.

The data in the table below shows the average lap times for each stint.

Comparison of Audi #1 and Toyota #7 Average Lap Times

Stint Driver #1 Ave. Lap Time No. of Laps Driver #7 Ave. Lap Time No. of Laps 1 Lotterer 1m 30.621s 34 Wurz 1m 30.419s 31 2 Lotterer 1m 29.863s 35 Wurz 1m 30.533s 32 3 Tréluyer 1m 30.157s 35 Lapierre 1m 30.268s 31 4 Tréluyer 1m 30.055s 21 Lapierre 1m 30.319s 32 5 Fässler 1m 37.440s 20 Nakajima 1m 35.022s 32 6 Fässler 1m 30.038s 17 Nakajima 1m 30.044s 31 7 Lotterer 1m 29.448s 36 Nakajima 1m 29.880s 31 8 Lotterer 1m 30.345s 35 Nakajima 1m 29.560s 13

As usual, I calculate the average lap time using the time from the pit out at the beginning of the stint (or across the start line for the first stint) until the pit in at the end of the stint (or the finish line for the last stint) and dividing by the number of laps completed. Thus the average lap time includes the ‘in’ and ‘out’ laps, but excludes the length of the pit lane (480m) for one lap of the stint.

Note that stint 4 for the Audi was interrupted by its collision with the Aston Martin. Stint 5 for both cars was affected by the appearance of the safety cars, hence the slower time. For the Audi, the stint was also shortened by the need to serve the resultant stop/go penalty. Stint 6 was then also short for the Audi as it was not allowed to refuel during the penalty – in fact stints 5 and 6 (either side of the stop/go penalty) were on a single tank of fuel and a single set of tyres. In effect therefore, Fässler only did a single stint, before handing the car back to Lotterer.

Note also that the average lap times for stint 5 are somewhat misleading: as the stint for which the average is taken is much shorter for Fässler than for Nakajima, the impact of the full course caution on the average is much greater. In fact, as we shall see later, the Audi gained from the appearance of the safety cars.

What I would really like you to observe from the table though, are the following points:

- In general, although the two cars were extremely closely matched, the Audi was nearly always just a little bit quicker, on average.

- Although double stinting the tyres on the Toyota did cost something in terms of the average lap time, it wasn’t as much as it would have cost had they changed the tyres on every stop.

- Nakajima’s times towards the end of the race are truly remarkable: each of his stints was faster than any of those of his co-drivers.

- The final stint for the Audi is slower. This was the only stint that the Audi did on used tyres, which tends to confirm that Audi’s strategy of changing tyres on every stop was the right one. It is an interesting question whether a tyre change on the final stop might have given Lotterer a better chance to catch Nakajima. Do the maths yourself and see what you think.

What’s noticeable here is how Audi’s strategy to change tyres at every stop (except the last one), does not cost it as much time as it would have cost Toyota. Audi’s slowest tyre stop was still quicker than Toyota’s quickest.

It’s hard to tell whether this was due to the refuelling or changing the wheels, but my research suggests that the Audi refuelling rate is 2.8 litres (of diesel, remember) per second, compared with Toyota’s (petrol) rate of 3.5 litres per second. If these figures are correct, then the time spent refuelling is around 20 seconds for both teams, but the wheel change time is under 24 seconds on average for Audi, but over 27 seconds for Toyota.

Finally, it is interesting to examine the impact that the appearance of the safety cars had, after the collision of Benoît Tréluyer in the number 1 Audi with Stefan Mücke in the Aston Martin left too much debris on the track to allow racing to continue. The full course caution lasted less than seven minutes, but both Audis managed to profit from it. I have explained on my blog how the number 2 car managed to save itself around 47 seconds by virtue of a quick decision (by Howden ‘H’ Haynes, on the pit wall) to pit when the safety car appeared.

The number 1 car also benefited, to the tune of up to 28 seconds depending how you do the calculation, just by the fact that the safety cars bunch the cars up into a queue before releasing them again. I’ll explain what happened, for the timing was crucial, as was the fact that it was fully five minutes between the contact on the circuit and the beginning of the safety car period.

Despite the collision between Mücke and Tréluyer, both cars continued. Although Tréluyer, in the Audi, clearly wanted to pit, engineer Leena Gade sent him on another lap while the team got the requisite parts ready. When the Audi pitted at the end of the next lap, Marcel Fässler took over, and would have re-joined a lap down, but for the fact that the leading Toyota, in the hands of Nicolas Lapierre, had made its fourth scheduled pit stop, handing over to Kazuki Nakajima.

Allan McNish thus took over the lead in the number 2 Audi, but within a few seconds, Race Director Eduardo Freitas decided to deploy the safety cars to neutralise the race and clear the debris off the track.

As McNish headed for the pit lane, Nakajima was left in the lead, one car between him and the safety car. Fässler, on his first flying lap, managed to get past the Safety Car ‘B’ line at the back of the track, before the second safety car was deployed, putting him behind the same safety car as Nakajima, albeit with twelve cars separating the two cars in the queue.

After three laps, the safety cars were withdrawn, and Fässler was only 12 seconds behind the leader. With a clear track ahead of him, Nakajima was able to increase the gap as Fässler fought his way through the traffic. Then, of course, the stewards decided that Tréluyer was at fault for causing the collision with the Aston, and the penalised the Audi accordingly.

Before the incident, Lapierre in the Toyota was 9 seconds ahead of Tréluyer in the Audi. About 9 seconds were lost as the Audi recovered and made its way back to the pits. The stop to replace the bodywork cost an extra 22 seconds, making a total loss for the Audi of 31 seconds. Without the intervention of the safety cars, then, the Audi would have been 40 seconds behind the Toyota. So in a sense, the stop and go penalty that was given to the Audi really only put it back where it would have been, had it not benefited from the safety car period.

Just as well, from Toyota’s point of view, as the race was so close, that it would have made the difference between winning and losing.

Paul Truswell