McLaren Formula 1 driver Stoffel Vandoorne has changed chassis for this weekend's Hungarian Grand Prix in a bid to remedy his long-running pace issues and lack of downforce.

Vandoorne has failed to make it through Q1 at any of the last four races, with his last points finish coming in Baku, leaving him 16th in the drivers' championship.

The Belgian has been struggling with a lack of downforce on his car for some time. Teammate Fernando Alonso revealed it was seen in the data that his own car had more downforce, suggesting the issue was with the specific McLaren MCL33 chassis itself that Vandoorne used.

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Vandoorne confirmed on Thursday that a swap had been made ahead of this weekend's race at the Hungaroring in a bid to offer an upturn in his fortunes.

"We have swapped the chassis, yes. It’s not a brand new one, it’s one we’ve used before, but that’s not a problem at all," Vandoorne said.

"The fact the team has put in a lot of effort to try and get everything ready obviously with a back to back race, was quite tight for the mechanics to make it happen. But I arrive here fresh, start from zero.

"The team put in a lot of effort to try and understand the problems we had."

Vandoorne said McLaren was yet to nail down what had been causing the loss of downforce on his car, but hoped some answers would follow after practice on Friday.

"There’s no specific area we can say ‘okay that’s what’s causing it’. Tomorrow we have a couple of tests in place across the cars to further understand," Vandoorne said.

"Hopefully tomorrow we can spot nothing, as that means the two cars are going to be good."