Barrichello: 2010 tougher for drivers

The veteran Brazilian is optimistic that the end of mid-race refuelling will encourage overtaking on-track as disparities between cars' performance will be greater as some handle better on low fuel and others when fully laden.

"I think there will be more overtaking most probably," he predicted. "I think it is going to be a mixed thing because there will be cars that are eventually better on low fuel than high fuel, or the other way around, so I think the grid is going to be a bit more mixed and that will allow more overtaking. Which hopefully we are going to get.

"It depends on traffic, but at least in the first couple of laps, when a guy makes a pitstop he's going to be able to overtake, but the difference on pace might be greater than a second and when we are talking that much it's an overtaking opportunity."

Barrichello and returnee Michael Schumacher are the only drivers in this year's entry who raced in the previous no-refuelling era. But Barrichello said now the racing will be flat-out from start to finish, whereas 17 years ago teams were often urging drivers to nurse the cars to ensure they finished.

"I think it's different from the 1993 times because we say we are looking after the car, but all we need to work is to go flat out from the beginning to the end with tyres and the amount of fuel you have on the car," he said.

"I remember '93 days when you had a board that said, 'keep it straight' or 'look after tyres' or 'look after the engine'. I don't think you will be able to do that anymore these days, you're just going to go flat out with what you have on hand."

He reckons this year's form is much harder to predict that at any other stage in his long Formula 1 career, even compared to 1993, which saw similar fuel load variations in testing.

"Right now it has never felt so open like this," said Barrichello. "In 1993, you had a Williams that was so far in front or a McLaren that was trying to get [Ayrton] Senna so was trying to go for quick times. In those days you had a lot of fuel on board too, but with the variations last year you knew it was 50 kilos, 60 kilos max. Some people would run 40.

"Now you are talking about 10 to 170! And that can add five seconds on things, so it's really open. It's really nice to have that type of challenge."