The Japanese manufacturer has revealed that problems with the clutch were the reason why the race-winning #8 Toyota GR010 HYBRID Le Mans Hypercar lost a handful of seconds at each pitstop to the second-placed sister car over the closing stages of the eight-hour race.
Toyota Gazoo Racing Europe technical director Pascal Vasselon stated that the problem became “critical” and that “during one stop we were nearly not able to restart the car”.
The clutch problem meant the drivers of the #8 had trouble restarting the car conventionally in the pits, forcing them to leave the box on electric power from the front-axle hybrid system and effectively bump start the GR010’s twin-turbo V6 engine.
“The clutch was not opening so we could not use the starter [motor],” explained Vasselon.
“We had to pull the car with the front, but the problem was that the cold tyres meant the fronts were spinning and the rears were not rotating.
“The tyres were dragging and not cranking the engine. It was taking quite a long time to get started.”
Vasselon explained that the TGR squad managed to mitigate the problem by bumping the car in second rather than first gear.
“In the end we went to start in second, which was better,” he said.
Vasselon could not put an exact total time loss for #8 that resulted from the problem, but he explained that it reared its head quite early in the race even though the “the last three pitstops have been the critical ones”.
He described the Bahrain 8 Hours WEC finale as “quite intense because we had problems on both cars”, even though Toyota notched up a fourth 1-2 finish of the season.
The #7 Toyota shared by Kamui Kobayashi, Mike Conway and Jose Maria Lopez that finished 47s behind the Hypercar title winners was hit by a problem with one of the driveshaft torque sensors that are mandatory in class.
This was a similar issue to the one that hit Kobayashi and his team-mates at the Portimao WEC round in April, restricting them to ninth position.
At Portimao an internal electronic component failed, but that this time the sensor on the driveshaft came apart.
New protocols introduced since the Portuguese race by the WEC rulemakers the FIA and the Automobile Club de l’Ouest to monitor power delivery in the event of such a failure meant the time loss for the car was much reduced in Bahrain.
“We are working more precisely in terms of back-up [now], but it is not exactly like normal, so to make sure we have no gain when these kind of things happen we have to detune the car,” he explained.
The problem on the #7 manifested itself around the halfway mark of the race, Vasselon said.
Had it beaten the #8 to victory on Saturday, Buemi and his team-mates would still have claimed the title.
They needed only to finish third in the event of their team-mates winning, after Hartley’s pole position gave them an extra point.
