Red Bull owner Dietrich Mateschitz has issued a new quit threat, saying his team is losing "desire and motivation" in F1 amid Renault's struggles.
Renault's power unit has been uncompetitive since the introduction of the new regulations at the start of the 2014 season. After winning three races last season, Red Bull has been further off the pace this year and has yet to even score a podium. Speaking to Speedweek, Mateschitz says there is too much holding the team back at present which is threatening his interest in F1.
"[Renault] take from us time and money, desire and motivation," Mateschitz said. "Because no driver and no chassis in the world can compensate for this power unit handicap.
"In addition, our chances were hurt because the aerodynamic regulations here are so restricted that designer Adrian Newey cannot show his full talents. We have already used up the fourth engine. So we are towards the back of the starting line-up. What needs to happen so that you lose interest?"
While Red Bull has a contract tying it to the sport until 2020, Mateschitz says there is every chance it could quit before then.
"How many teams have dropped out of Formula One, despite already having contracts? You cannot hold someone back if he wants to get out."
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