How Audi inherited the 2016 6 Hours of Spa-Francorchamps after Toyota's smoke

Audi's No. 8 car inherited the lead at the 2016 6 Hours of Spa-Francorchamps after Toyota's Sebastien Buemi had to go back to the garage with smoke from his engine. Oliver Jarvis, Lucas di Grassi and Loic Duval went on to win, the first overall victory of the season for Audi and the first World Endurance Championship win for Jarvis and di Grassi.

Why was Spa important in the 2016 season?

The 2016 WEC 6 Hours of Spa-Francorchamps was the second of nine endurance rounds that season and the fifth running of the event within the championship. The race ran from 5 to 7 May 2016 at Stavelot in Belgium, on a 20-turn layout measuring 7.004 km (4.352 mi), and many teams treat it as a final test before Le Mans.

Endurance racing has a long history at Spa. The first Spa 24 Hours was run in 1924, and the track later hosted 500 km and then 1,000 km World Sportscar Championship races. Those events were cancelled after the 1975 running because of modern safety concerns, and they returned in 1982 on a reconfigured layout.

Spa began holding endurance sports car races again from 1999, and the 6 Hour event became part of the World Endurance Championship in 2012. The track's high average speed and abundance of elevation change push teams towards maximum downforce and minimum drag.

Toyota chose a high-downforce specification that gave it an advantage in the second sector. The teams tested their aerodynamic changes in a two-day session at MotorLand Aragon in April, and Aston Martin was allowed to cut 20 kilograms (44 lb) from the minimum weight of its cars.

Audi inherited the lead when Toyota's engine smoke sent its driver to the garage, and the win came after a long day of stoppages.

What did the championship look like before Spa?

Porsche's Porsche's trio of Lieb, Jani and Dumas topped the Drivers' Championship on 25 points apiece. Kamui Kobayashi, Mike Conway and Stephane Sarrazin were seven points back, and Dominik Kraihamer, Alexandre Imperatori and Matheo Tuscher were a further three behind them.

Toyota led the Manufacturers' Championship on 33 points, eight ahead of Porsche, while Audi had one point. Porsche had won the Silverstone round after the No. 7 Audi was disqualified for a worn skid block, so the Spa result mattered to every contender.

Dumas said Porsche had to stay focused, remain calm and avoid mistakes, because the team had not been able to win the previous Spa race. Hartley, who was looking forward to the circuit because it is one of his favourites, hoped his World Drivers' Championship defence would be revived there.

What did practice show at Spa?

Practice ran over three sessions: two 90-minute periods on the Thursday and a one-hour session on the Friday afternoon. Hartley set the fastest time of the first session at 1:58.012, almost six-tenths of a second clear of his teammate Jani in second.

The second session was cooler, and Sarrazin in the No. 6 Toyota was fastest at 1:58.566, set early in the 90-minute period. Nakajima was second-quickest and Webber third in the No. 1 Porsche, while the second Audi did not run because its mechanics could not repair a failed front axle drivetrain.

Roberto Merhi was the only LMP2 driver under 2:08, with 2:07.865 in the No. 45 Manor Oreca, and van der Garde's G-Drive car trailed him by eight-tenths. That session ended early when Yutaka Yamagishi dropped fuel on the track and hit the barriers at Stavelot corner.

The final practice session was sunny. Bernhard's 1:56.456 was the quickest lap yet, 1.6 seconds better than the best of his teammate Jani. Loic Duval made contact with Christian Ried's Proton Porsche into the Bus Stop chicane and had to repair the front-left bodywork in the garage.

Rast was the quickest LMP2 driver in that session with 2:07.341, while Nelson Panciatici's Signatech Alpine was four-tenths slower. Gianmaria Bruni set the quickest LMGTE Pro time, with Davide Rigon behind him, and Paolo Ruberti was fastest in LMGTE Am in the Larbre Competition Chevrolet.

How did qualifying settle the front row?

Timo Bernhard took pole in the No. 1 Porsche with an average lap of 1:55.793, the team's first pole of the season. Jani and Lieb lined up alongside him on the front row, just behind Bernhard's pace. Audi's qualifying effort, by contrast, left the team fourth and sixth.

Audi and Toyota fought for positions three to six. Audi struggled to find a set-up and qualified fourth and sixth, with the two Toyotas in third and fifth. Marcel Fassler abandoned his first attempt in the No. 7 Audi after losing rear downforce behind two cars at Blanchimont, which left the car sixth.

In LMP2 Rene Rast and Roman Rusinov took pole for G-Drive Racing with 2:07.363, a new class record at the track. In LMGTE Pro Sam Bird and Davide Rigon of AF Corse set the pace at 2:17.644, and the No. 98 Aston Martin of Paul Dalla Lana and Pedro Lamy took LMGTE Am pole by 1.8 seconds.

After qualifying the stewards reprimanded six drivers for a slow reaction to the red flag. The fastest laps of three cars were disallowed for track limits, which moved Gulf Racing's No. 86 Porsche from sixth to fourth in LMGTE Am. Michael Christensen missed the 107 per cent mark and was prohibited from starting, so Richard Lietz took over his starting duties.

How did the race start at Spa?

The weather was dry and sunny at the start, with the air between 20 and 24.5 C (68.0 to 76.1 F) and the track between 24 and 52 C (75 and 126 F). Hartley kept his pole advantage into the first corner, and 56,000 people attended the event.

Elsewhere, the No. 8 Audi moved from fourth to third early on, while the second Audi went from sixth to fourth by Les Combes. In LMGTE Pro Bruni passed teammate Bird to take the lead on the first lap, after Vitaly Petrov suffered a right-rear puncture in contact with another car and had to stop for new bodywork.

Benoit Treluyer, in the No. 7 Audi, was pressured by the two Toyotas, with Conway driving close behind him into the Bus Stop chicane. Derani and Panciatici made contact at Les Combes, but both continued without major damage.

Lieb slowed with a hybrid system problem around 20 minutes in, which meant he could not use the full electric power of his car for the rest of the race. He dropped to sixth, and his team told him to keep the car on track and manage the problem, because Porsche needed the points.

Why did the lead change hands so often?

Buemi did not change tyres at the first pit phase and so took the overall lead. Smoke then billowed from his engine and sent him back to the garage for repairs, and the No. 8 Audi inherited the lead. The car that took the lead was not the one that started on pole.

Separately, Buemi had also gone wide at Raidillon while pushing to extend his advantage, and at La Source he lost the lead to Bernhard. Bernhard reported a front-left puncture after running over debris, and he gave up driving to Webber, who took over the Porsche.

Webber slowed with a punctured front-left tyre and returned for ten minutes of bodywork repairs. His front-axle energy retrieval system was then changed, and he stayed in the garage for more than an hour, which cost the No. 1 Porsche a great deal of time.

What happened in the closing stages at Spa?

The first full course caution came after Dolan's No. 38 G-Drive car struck Nicki Thiim's No. 95 Aston Martin, which went backwards into the Stavelot tyre barrier at high speed. The car flipped over, but Thiim was unhurt, and marshals had to repair the barrier.

A second full course caution came after debris was found on three sections of the track. Stefan Mucke then crashed heavily at Raidillon, losing both doors from his No. 66 Ford, and he was taken to the medical centre for checks on leg bruising and a cut to his leg.

Late in the race the No. 7 Audi was spun by Albuquerque's RGR Sport car at La Source and was heavily damaged at the front, leaving debris on the circuit. Calado's engine failed in LMGTE Pro, and Derani and Lapierre fought for the LMP2 lead as the race wound down.

Who won each class at Spa in 2016?

The No. 8 Audi of Jarvis, di Grassi and Duval won outright, and the Porsche of Dumas, Jani and Lieb finished two laps behind in second. Rebellion Racing took third in the overall order. The margin between the overall winner and the second car was two laps.

Lapierre, Gustavo Menezes and Stephane Richelmi won LMP2 for Signatech Alpine. Derani was second for Extreme Speed Motorsports, and Menezes and Richelmi earned their first WEC class wins.

In LMGTE Pro, Bird and Rigon took their second consecutive win for AF Corse in the No. 71 Ferrari. The Ford of Priaulx, Franchitti and Tincknell finished second, its first podium in the WEC, and the No. 97 Aston Martin took third. In LMGTE Am the No. 98 Aston Martin won by one lap from the AF Corse Ferrari, a car that had been on pole for its class.

How did the result change the standings?

Lieb, Jani and Dumas kept the Drivers' Championship lead with 43 points, 15 ahead of third-place Kraihamer, Imperatori and Tuscher. Porsche extended its Manufacturers' Championship lead to 56 points, 13 in front of Toyota. The Porsche's second place kept the team in contention for the manufacturers' title.

Jarvis was unhindered in the final hour and crossed the line to clinch Audi's first overall win of the season, which he admitted the team had not expected from the car's lap times.

Di Grassi called the day crazy and said the team had not expected to win, while Duval said the team deserved the result. Jarvis admitted the car's lap times over the weekend had not suggested a win was likely.

Imperatori said third was a dream result for Rebellion and set the aim of repeating it at the next race. Lieb said the loss of hybrid power early in the race had been frustrating.

What did the Toyota drivers expect from Spa?

Toyota's Anthony Davidson said the race would show the team which segments needed attention before Le Mans. Kazuki Nakajima, who had missed the previous year's race through injury, said he was pleased to return to the circuit. Toyota's high-downforce package was the main experiment for the weekend.

Both drivers were realistic about the Toyota package. The team had to balance its high-downforce set-up against the speed of the cars around it, and Davidson said the race would indicate where the team stood before the French endurance classic.

Spa 2016 class winners