Still reflecting on Le Mans – some speculation.

It is partly due to the long break since Le Mans, but it is also in my nature to reflect on such matters; but I am still wondering how Porsche won the world’s most important endurance race. I have said elsewhere that it was as much a case of Audi, Toyota and Nissan losing the race as it was Porsche winning, and in the last quarter of the race a degree of inevitably developed about the destination of the winner’s spoils. The two leading Porsches had run routinely, and if there had been doubt about their reliability at the start of the race, the absence of any pressure from rivals made it hard to foresee mechanical woes interrupting their progress to the chequered flag in the final 100 laps.

But who were the heroes at Porsche? What were the deciding factors? Can Porsche win again in the remaining races of 2015? Will they make Le Mans 2016 look as easy as they did this year? Nico Hülkenberg, Nick Tandy and Earl Bamber, driving the winning car, of course received – and deserved – the greatest plaudits, but they won’t be driving in the remaining championship rounds this year.

Furthermore, a close look at the evidence suggests that their car somehow had an edge over the other two Porsches. The table below shows the average of the best 20% of laps completed for the three of them:

Car No.	Drivers	Race Ave. Lap Time
17	Bernhard/Webber/Hartley	3m 20.609s
18	Jani/Lieb/Dumas	3m 20.731s
19	Hülkenberg/Tandy/Bamber	3m 20.040s

The driver breakdown, per car, looks like this:

Car No.	Driver	Average Lap Time	Laps Completed
17	Timo Bernhard	3m 20.352s	144
	Mark Webber	3m 21.069s	107
	Brendon Hartley	3m 20.604s	143
18	Neel Jani	3m 21.053s	162
	Marc Lieb	3m 20.858s	100
	Romain Dumas	3m 20.449s	129
19	Nico Hülkenberg	3m 20.053s	144
	Nick Tandy	3m 19.852s	120
	Earl Bamber	3m 20.219s	131

However good the drivers of the no. 19 car were at Le Mans, I will take some convincing that they are more than half-a-second a lap faster than the other Porsche drivers, so one has to conclude that the car had some kind of advantage.

Now it is not unheard of, even in this day and age, that one car on a team of three just finds the sweet spot: whether it is the ride height, tyre pressures, camber angles, aero trim or just the right combination of all of these. In my analysis for dailysportscar.com though, I suggested that the answer might lie in the fuel flow meters, and I have not changed from that opinion, although I accept that it is speculative.

While at Le Mans, I fell into conversation with Dan Partel, who is now the chairman at Sentronics Ltd, a company that manufactures fuel flow meters in competition to GILL, which is (or rather, was) the only FIA-homologated manufacturer of fuel flow meters for the WEC. He was expecting Sentronics to be added to the list “before the end of the season”, and lo and behold, on July 2nd, an update to the FIA Technical List No. 45 was issued, allowing LMP1 teams to use Sentronics’ AE-040-01 meter forthwith in WEC races.

If the advertising is to be believed, this meter offers better accuracy than the Gill product, although it is slightly heavier. It remains to be seen what impact, if any, the availability of the new meters will have at the next WEC round at the Nürburgring, but surely choice, competition and a free market will not do any harm.

Moving on, and regardless of the vagaries of fuel flow meters and their manufacturers, it was something of a surprise – and it remains a mystery to me now – why the Porsches at Le Mans chose to do 13-lap stints.

As a consequence of running in the 8MJ per lap category, Porsche was restricted to burning fuel at a maximum rate of 138MJ per lap. The regulations permit 68.5 litres of fuel to be carried, which should easily allow 14 laps of the 13.6km circuit. So clearly this was a strategic choice by Porsche. Theoretically, breaking the race into 14 lap segments would have allowed Porsche to complete the race on twenty-eight, rather than thirty pit stops. This would have saved at least 90 seconds on their total race time.

Certainly, by stopping every 13 laps, they were putting in less fuel, and thereby saved time on each pit stop. However – and here is the mystery – the fact that less fuel was needed at each stop only accounts for just over two seconds per stop. Porsche was on average nearly five seconds per stop quicker in the pits than Audi (for fuel-only stops).

I have no explanation for this, so I need to speculate again. One possibility is that by pouring fuel into a tank that already had fuel in it, there was less turbulence during the refuelling process, allowing the fuel to flow in more quickly.

I’m hoping that some of these questions might be answered during the Nürburgring Six Hours. One thing which is going to play into Porsche’s hands is that the Endurance Committee has met and decided that teams should be allowed to use eight sets of tyres for the Nürburgring race (just as they are for the races at Bahrain and Shanghai), rather than the six sets that were allowed at Silverstone and Spa. There is no getting away from the fact that Porsche’s tyre loading problems caused significant delay for them at Spa, so this will be good news indeed for the Le Mans winners, as they try to stop Audi steamrollering to the WEC title as some compensation for losing Le Mans.

It seems like it has been a long time since Le Mans, and the next round of the World Endurance Championship at the Nürburgring is still more than six weeks away. In the meantime, I have a visit to the Spa 24 hours, round 4 of the Blancpain Endurance Series, to distract me. A 58-car entry list (25 of which are in the Pro Cup) and a tremendous race between Audi, BMW, McLaren, Bentley, Lamborghini, Mercedes, Nissan and Aston Martin in prospect.

After that, I’m off on holiday for a welcome rest and some relaxation. Life is certainly not dull these days!