How Jenson Button did that lap time

Everyone is buzzing with the performance of the new Brawn Mercedes car in Barcelona, particularly that lap Jenson did on Wednesday of 1m 19.127 to end the day fastest.

There is a lot of speculation within F1 circles and the wider public about how he did that time, whether it is genuine or whether they are running an underweight car to attract sponsors, as some teams have done in the past.

Even Fernando Alonso has paid tribute to the Brawn team today, saying that his Renault couldn't do those lap times whatever configuration it was in!

Well I've taken a close look at the data I've gathered and there is no doubt that this car is performing remarkably. We will only know whether it has been running underweight when we get the first two races out of the way and we can see what the relative performance of the Brawn to the BMW and Ferrari is when they all have to be the minimum weight.

Jenson did the lap time on the third lap of a four lap run. What is interesting about it is that his first flying lap was a 1m 19.229, so already very quick on the first lap, then he goes faster again. It was a qualifying simulation, of course, but he found more from the tyres on the second flying lap.

Whichever way you shake it, this was a massively quick time and reminiscent of the pre-season tests in 2004 when he did similar things, everyone thought it was underweight showboating, but the team went on and finished second in the championship.

As for their long run pace, this too is equally impressive. Jenson did a 22 lap run with laps mostly in the 1m21s and high 1m 20s. On Wednesday in Barcelona not too many other cars were doing long runs at that speed. Massa's Ferrari does a 20 lap run with laps in the low 1m21s.

So on the face of it, as Alonso says, the Brawn is as fast as the Ferrari, which is amazing if the car is running at its legal weight. Bear in mind that Ferrari is running KERS and Brawn is not, so there is a weight advantage to Brawn. And the Brawn is able to put its ballast where it wants it, to improve weight distribution. But on the other hand the Ferrari has the performance boost of the KERS button on the straights - Massa is 8km/h faster across the start line than Jenson.

Jenson does another long run, this time 21 laps, eight of which are in the 1m 20s, again super-competitive.

They've been working on their 2009 car for longer than any of their rivals, having effectively written off the 2008 season before it started! They've made the work count and you can see why the team were so frustrated that Honda panicked when it saw the November sales figures and pulled the plug on F1.