F1 Chinese GP: Titanium spark plate caused Williams cockpit smoke

Massa complained of smoke in the car during practice on both Friday and Saturday at Shanghai, responding with "I'm never happy with smoke in the cockpit!" when the team radioed him suggesting he continue anyway during a practice three run.

The Brazilian explained that a low ride-height was causing excessive bottoming and the effect of the titanium led to the smoke.

"They changed the floor, they put titanium on for the show, to have some sparks and here is the longest straight we have in the season," said Massa.

"The car was too low and touching [the track] too much.

"That is why we had the smoke and we put the ride height up and it was not there anymore."

After struggling in the Malaysian GP, Williams has been closer to the pace in China, with Massa and Valtteri Bottas qualifying between the Ferraris in fourth and fifth.

The team's head of vehicle performance Rob Smedley said the form at Shanghai so far proved Sepang had been an anomaly.

"We pretty much understood that we had a problem with the tyres and that it was important that we a) analysed that thoroughly which we now have done and it's pretty much as we thought after the race - that we had the tyres a little bit too hot - and then b) thought about counter measures for it - and that's an ongoing process," he said.

"It wasn't an aerodynamic problem, it wasn't a mechanical problem, there wasn't anything wrong with the inherent performance of the car.

"What was wrong was with the way we were operating the tyres, so we went away and thought about that a bit more.

"I fully expected that in China we would be back to a more reasonable position.

"Not where we want to be by any means, but a more reasonable position."

Bottas was two tenths of a second slower than Massa, which he put down to overheating his tyres.

"Overall we had more grip from the tyres than in practice, so we managed to create a bit more temperature in the tyres, which was good," he said.

"But then in Q2 from run two onwards I really struggled with my rear tyres.

"Now we see after qualifying that there was quite a difference between the cars in the rear temps, so I was cooking my tyres too much in the out-laps.

"We only noticed it after qualifying, we thought we were ideal but we were actually too high with me."