McLaren suspects that the form of its 2014 Formula 1 car is being dictated by the weather.
On the back of a disappointing Chinese Grand Prix, where Jenson Button and Kevin Magnussen failed to finish in the points, McLaren's lack of downforce has been exposed.
That means the team can only shine when the temperature is in the right range to allow its tyres to get in to the right operating window.
When asked by AUTOSPORT about why the car has been able to show flashes of speed this year, McLaren racing director Eric Boullier said: "To be honest, what is difficult to explain is that if you look at Bahrain, except for Mercedes, we were chasing the Force Indias and we could have, with a better strategy, even finished on the podium.
"So it seems the performance range our car works in is weather dependent. If it is too hot we are out, if it is too cold we are out.
"We are missing downforce, so we cannot exploit the tyres as easily as Mercedes and Red Bull."
With McLaren having failed to bring home any points for the second race, Boullier confessed to China having been harder to accept than the double retirement in Bahrain.
The Bahrain retirements were caused by a clutch failure that came about because the team tried an unproved gear-change setting in a bid to find more lap time, whereas the team was just off the pace last weekend.
"It is obviously bad - but it is even worse, to be honest," said Boullier of the Chinese GP showing.
"If you try something [like the Bahrain gear-change gamble] because you are under pressure that is one thing. I accept an honest mistake.
"I don't accept it because something went wrong, but you can make this kind of mistake. But to have a DNS (did not score) - that hurts."
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