How Porsche's 'extras' won Le Mans

Porsche added to its tally of victories in the Le Mans 24 Hours at only the second time of asking since its return to the pinnacle of sportscar racing last season.

Nico Hulkenberg, Nick Tandy and Earl Bamber led home a one-two for the Porsche 919 Hybrid on a day when the returning king of Le Mans had an edge on arch-rival Audi out on the racetrack, in the pits and in the reliability stakes.

The honour of notching up Porsche victory number 17 and a first since 1998 fell to Hulkenberg, Tandy and Bamber because they were the fastest of the three Porsche combinations — most pertinently the quickest when the Stuttgart manufacturer was able to push home its advantage during the night — and ran into not a single problem.

Theirs was an almost perfect race, interrupted only by a quick stop into the pits for a precautionary change of the rear body section under the safety car at at 8am on Sunday morning.

The #19 Porsche came into its own as temperatures dropped over the Circuit de la Sarthe on Saturday evening, and then some when it got even cooler as darkness fell.

The #19 crew featured two drivers with no Le Mans experiene and a third making only his second LMP1 start © LAT

Le Mans rookie Hulkenberg, who became the first active Formula 1 driver to win Le Mans since Johnny Herbert and Bertrand Gachot did the business for Mazda in 1991, proved that the #19 entry was going to be a contender when he climbed aboard the car for a second time late in the sixth hour.

The car had lost time during the first two of the four safety cars to interrupt the 83rd running of the Le Mans 24 Hours, but Hulkenberg was up into the lead group by the time the safety car came out for a third time at the end of hour eight.

The Force India driver — making his Le Mans debut, remember — passed team-mate Mark Webber in the #17 Porsche for second before handing over to Tandy, after completing the car's first quadruple stint on a set of Michelin tyres.

Tandy, the only driver in this additional entry for Le Mans to have previously raced in the 24 Hours, continued the good work either side of midnight, before Bamber established the car in the lead in the small hours.

Neither the Webber car, which the Australian drove to second place along with Timo Bernhard and Brendon Hartley, nor Audi had the pace of the winning Porsche at this crucial stage of the double-points World Endurance Championship round.

"We weren't quick enough," said Webber. "The #19 car was faster than us, especially in the night. It left us and the Audis behind."

Tandy didn't disagree.

"The track came to us when the temperatures came down at dusk," he explained.

The winning car stretched its advantage at night © XPB

"It was all about doing four stints on the tyres and we were able to keep a good pace throughout.

"I think that was the key to our victory. Those cooler conditions suited the way we and our car were working."

Porsche couldn't explain the performance differential at night between the #19 and #17 cars, LMP1 team principal Andreas Seidl insisting that the respective set-ups of the two cars were pretty similar.

"Maybe, it was just that the three winning guys felt comfortable in their 919 and adapted better to the conditions," he suggested.

Audi offered more of an explanation for why it couldn't keep pace with the #19 car in particular and Porsche in general during the night.

"We had times at night when we were not quick enough, which was down to the temperatures," explained Audi Sport Team Joest boss Ralf Juttner.

"As soon as you say that, people think you are talking about the tyres, but it wasn't the tyres. These are very complicated cars that are sensitive to changes in temperature."

The Audis were mostly losing out in sector two at Le Mans — basically the Mulsanne Straight and its two chicanes — at night. The conclusion must be that the R18s lost power at night.

Bernhard reckoned that his 919 was at least a match for the winning car in the daytime, but after the car was given a one-minute penalty in the ninth hour for a yellow-flag infringement by Hartley early in the race there was no way back.

The #17 car didn't catch up until the formation finish © XPB

The car was more than two minutes down after Webber took the penalty and more or less kept the gap stable until slipping off the lead lap in the 22nd hour.

Bernhard and co were by that stage well clear of any challenge from Audi.

The low-drag version of R18 e-tron quattro that had been given a winning debut in the Spa WEC round last month was capable of keeping pace with the Porsches — at least on the track — in the daytime even if it wasn't a match for #19 in the night.

There was no chance of a fightback when the temperatures rose on Sunday morning because all three of the cars had been delayed.

Andre Lotterer, Marcel Fassler and Benoit Treluyer ended up two laps down in third position. They still had a sniff of a second consecutive victory and a fourth in five years on Sunday morning, until just before 7am when part of the rear bodywork peeled back on Fassler out of the Porsche Curves.

A delay of two laps, then a drive-through penalty after Fassler was alleged to have disrespected a slow zone and further unscheduled stops for a top-up of oil and more attention to the bodywork, meant the deficit was not reduced at the finish. More than once did the car take a lap back on the Porsche ahead, but each time the rival was ahead again after the next pitstop.

That underlined Audi's problem at Le Mans this year.

Audi thought it could overcome its disadvantages © XPB

It knew it was going to have to play catch-up to the Porsche from the first round of pitstops. It was immediately apparent that the petrol-powered 919 was going to require less fuel at each stop than the R18 turbodiesel, with the saving of about four seconds each time.

Rivals Audi and Toyota had predicted that the the new-for-2015 919 would go an extra lap on each tank of fuel courtesy of Porsche's move into the eight megajoule hybrid class, but a 14th lap of the 8.47-mile circuit just proved out of range under green-flag conditions.

"If you can only do 14.0 laps, you don't do it, because you don't have a safety margin," explained Porsche man Seidl. "So if you put in fuel for 13 laps, you are saving on car weight and refuelling time."

Audi calculated that the time it was losing in the pits would add up to two and a half minutes over the course of the race. The feeling in the Audi camp was initially that that disadvantage was not insurmountable, especially at a time when Porsche was still only triple stinting its tyres before switching to quadruples like Audi.

"Four or five hours into the race, we were quite optimistic" said Juttner, "but then it got cooler..."

The #9 Audi shared by Marco Bonanomi, Filipe Albuquerque and Rene Rast challenged the Porsche along with the #7 car and remained Audi's last hope — albeit an increasingly distant one as hybrid issues intervened — for a 14th Le Mans victory past three-quarter distance.

The hybrid problem meant the team needed change the front-left brake disc, which forced it to change the entire corner (the fastest way of dealing with the problem). A total of eighteen minutes were lost, which meant the car could finish no better than seventh.

Loic Duval, Lucas di Grassi and Oliver Jarvis ended up fourth, a further lap behind Lotterer and co. They lost a lap in the third hour when the first-named hit the barriers at Indianapolis in what turned out to be a phantom slow zone.

Damage hampered the #8 Audi © XPB

The accident happened after Duval had been told that the slow zone (in which the cars must slow to 60km/h) had cleared.

The problem was that one of the flashing boards at the side of the track just before the right-hander at Indianapolis was still yellow.

The teams had been told to inform their drivers that there might be an erroneous signal, but not all were as well informed as Duval.

The car was, reckoned di Grassi, "only 95 per cent" after its accident. Two stops on Sunday morning to address an identical rear bodywork fixation problem that hit the #7 Audi pegged them back when it looked like they might beat the sister car to the final spot on the podium.

The #18 Porsche driven by pole winner Neel Jani, Romain Dumas and Marc Lieb ended up four laps down in fifth.

A braking issue resulted in Dumas going off at Mulsanne Corner and hitting the barriers square-on early in the seventh hour and then Jani having a carbon-copy accident in the 11th hour.

Time was lost extracting the car from the gravel each time and replacing the nose in the pits, but the problem forced the drivers to shift the brake bias to the rear. This blunted the performance of the car and left them with little or no chance of fighting back.

Le Mans this year was a two-horse race between Porsche and Audi. Toyota wasn't even remotely on the pace.

Toyota was never in the hunt © XPB

Its lack of form meant that the best of the Toyotas was only able to finish ahead of the significantly-delayed #9 Audi. The #7 and #8 cars, even with their trials and tribulations, were too far up the road.

The fastest of the Toyotas ended up eighth after Anthony Davidson ran into the back of a GTE car, damaged the nose of his TS040 and then understeered off in the Esses.

The car spent 13 minutes in the garage and left the Briton and team-mates Sebastien Buemi and Kazuki Nakajima nine laps in arrears at the finish.

That put them only a lap behind the sixth-place sister car of Alex Wurz, Stephane Sarrazin and Mike Conway, which had a clean run.

There was no sense of shock in the Toyota camp after the race. It always knew it was going to be off the pace, but it was more surprised at the reliability of its rivals.

"Some things were as we expected and a few things weren't," said Toyota Motorsport GmbH technical director Pascal Vasselon. "We expected that we would not be fast enough, but we didn't expect the others would be so reliable.

"We have a big deficit across the board to Porsche and Audi. We estimated that we would be missing 20 minutes, and we were not far off in our prediction."

Toyota's hope was that the frontrunning cars would spend that amount of time or more in the pits, just as they did last year. An absence of major problems meant there was no chance of a decent result for either of the TS040s.

Nissan had a multitude of problems © LAT

Nissan endured a torrid return to the top class at Le Mans with its radical front-wheel-drive GT-R LM NISMO, but took solace from the fact that it got one of its three cars to the finish.

It claimed it was a case of mission accomplished, even though the best time by a GT-R LM was 18 seconds slower than the fastest lap of the race and only eight tenths quicker than the fastest LMP2 prototype powered by its own engine.

It fell a long way short of the promise Nissan global motorsport boss Darren Cox was still making immediately ahead of the race that its cars would lap "significantly faster" than the best of the P2s.

Nissan, which billed this race as an extended test session for a debuting design short of running coming into the event, was in trouble from the start.

The #23 car shared by Olivier Pla, Jann Mardenborough and Max Chilton started the race late courtesy of clutch problems, which set the tone for the rest of the race.

The Nissans encountered a variety of problems, not least of which was a collision with a giant piece of debris for Harry Tincknell in the night.

Braking issues were one of the bugbears for the US-based team, which looked as though it might get two cars to the chequered flag until Mardenborough stopped on circuit with suspension problems with 90 minutes to go, to join the #21 car of Tsugio Matsuda, Lucas Ordonez and Mark Shulzhitskiy on the list of retirements.

No fairytale for Rebellion this time © LAT

Tincknell, Michael Krumm and Alex Buncombe did finish, though they completed only 260 laps compared with the race winners' 395. That put it outside of the minimum 70 per cent distance required for the car to be classified.

Rebellion Racing was the top LMP1 privateer home, just as it had been in three of the past four years. But there was to be no fairytale result akin to its fourth-place finish last year.

Both of the revised R-Ones, now with AER turbo power rather than Toyota normally-aspirated motivation, made it to the finish, but they were classified down in 18th and 23rd places respectively after a multitude of problems.

The AER-engined version of the R-One didn't prove reliable but it was quicker than its predecessor over a lap. That wasn't a bad effort considering that the 2015-spec car had run for the first time less than a month before the race.

Reliability wasn't Audi's strong suit at Le Mans this year, even if all three of its cars were running at the finish. Porsche, by way contrast, had the bulletproof car.

Porsche knew it would have the pace, but it wasn't expecting to be so reliable.

"We couldn't expect to have no issues at the speeds at which we were running," Seidl revealed.

And that left Audi no chance of winning, as Juttner was happy to admit.

"If you have as many issues as we had and are fighting against someone who has a perfect race," he said, "then you have no chance."

For the full story of the 2015 Le Mans 24 Hours and in-depth reports on the LMP2, GTE Pro and GTE Am races plus the race's other major talking points, see this week's AUTOSPORT magazine - available on Thursday June 18