So, the World Endurance Championship arrives at the Circuit of the Americas in Texas this weekend for round five of the eight rounds that compose the championship.
There is no shortage of preview material out there on the Internet, so instead I shall plough my own furrow here, using the data from previous races to make some predictions that I hope are not too far wide of the mark.
This is the third time that the WEC has visited this venue - readers may remember that last year’s race had to be stopped due to torrential rain. It was restarted after a delay of more than three-quarters of an hour, and cars ran behind the Safety Car for four laps before the green flag was shown, so all in all more than an hour of racing was lost. Therefore, comparisons with the race distance of 157 laps in six hours are meaningless.
In 2013, 187 laps were completed by the winning Audi e-tron quattro, driven by Tom Kristensen, Allan McNish and Loïc Duval. What none of us knew at the time, was that not only would it be Allan McNish’s last win in the WEC, but Tom Kristensen’s also - the Scot retiring from full-time racing at the end of that year, and the Dane at the end of last year.
It is likely then, that the record of 187 laps from 2013 will be beaten this year – I estimate that the race distance could be somewhere between 190 and 195 laps, if it is dry and the race is free of yellow flags. Furthermore, the winning Audi made seven pit stops in 2013 and used 371 litres of diesel and the second-placed Toyota, which completed the same number of laps, also made seven stops, and used 443 litres of petrol. This year, Porsche and Toyota will be limited to 389 litres (petrol) to cover the same distance, and Audi to 324 litres of diesel.
Also, it seems clear that the race this year will be a seven-stint race (six stops) – I reckon that both Audi and Porsche will be stopping every 29-30 laps, and that means that the minimum stint length (without needing to add an extra stop), will be 22 laps. In other words, if there is rain, a full course yellow, or someone suffers minor damage or a slow puncture, and they have completed more than 22 laps, then it makes sense to stop immediately. Otherwise, drivers will be encouraged to stay out and “drive around the problem” to avoid the need for an extra pit stop.
What about the lap times, though? I wouldn’t be surprised to see Porsche averaging 1m 48.2s per lap over a 30-lap stint, given the kinds of times that the two 919 Hybrids were managing at the Nürburgring. Quite where Audi will be will depend on whether they are able to find the right aero balance. This was clearly lacking at the Nürburgring, and Audi found themselves half-a-second (on average) slower than the Porsches, even though they had a 5km/h advantage through the speed trap.
Consider this also: the Six Hours of the Circuit of the Americas is a 24-tyre race (for the LMP1 cars, for qualifying and the race – plus two ‘joker’ tyres). If the Porsche is producing more aerodynamic grip than the Audi, it may be that it is the Audis that struggle to make the tyres last for two stints, rather than the Porsches, as it was in Spa-Francorchamps.
The rear bodywork of the Porsches caused some eyebrows to be raised at the Nürburgring, as it featured some extensions to the wheel-arches that appeared to go over the rear bodywork. There were suggestions that this was in contravention of paragraph 3.6.2 of the Technical Regulations.
Of more concern to Audi, however, was the fact that Porsche’s pit stops continued to be four to five seconds faster. Some of this is obviously due to the fact that Porsche are putting in less fuel at each pit stop, but there are still two aspects that have to be explained: why do the Porsches stop earlier than they need to (for refuelling)? And how do they manage to get the fuel into the car so quickly? I believe the answers to these two questions are linked, but until I get confirmation from the team, I will speculate no more.
The weather forecast suggests that it will be a warm, dry race, with temperatures soaring into the thirties (Celsius) for the start, and only dropping to around 27 deg. by the 11pm finish. Very similar, in fact, to the temperatures we had for the Nürburgring race.
The folk at Porsche must be rubbing their hands together in glee.