McLaren to keep blown diffuser on

Plans to get some extensive running of the revised floor, which included exhaust tweaks and improved heat shielding, were scuppered by poor weather conditions and a hefty crash by Lewis Hamilton in the first practice session.

And although that meant neither Hamilton nor Jenson Button were able to make much of an impression on the timesheets in the quicker afternoon session, McLaren still believes the blown diffuser produced enough of a benefit for it to remain on the cars for qualifying and the race.

When asked by AUTOSPORT for his prognosis on the diffuser plans, McLaren team principal Martin Whitmarsh said: "Based on the data we will be running it. The problem with today in a sense is that, with the limited running we had, it was difficult for the driver to go out and say this is the way to go. So you have to rely on data.

"The data that I saw from P1, albeit wet, was that the main peak airflow, the gas flow from the exhaust, temperatures, the performance, and the pressure tapping velocities were what we expected them to be.

"So unless something else has come to fruition, which I don't think it has, we should have the confidence that this floor will do everything we expected it to or most of what we expected it to."

Although Hamilton's crash in P1 meant his running was limited to the final few minutes of the afternoon session, Whitmarsh reckons that the team had actually not lost out too much because of the changeable weather that affected everyone's plans.

He also confirmed that McLaren was able to rebuild Hamilton's car into the exact same specification it had been prior to the crash - despite it having suffered damage to all four corners.

"We lost a little bit, but on the other hand it was a bit of a scrappy day for everyone wasn't it?" said Whitmarsh. "When those things happen, which they do periodically and if they don't then people aren't trying hard enough, then if it is a wonderful dry consistent and progressively slowly improving track you miss out on doing all the homework.

"Jenson did quite a lot of high fuel running in P2, Lewis did not, he would have done, and Lewis did not run an option tyre either.

"And actually I have to congratulate Lewis. He was getting out there late. I was niggling the engineer to say, have a run and then come back and do an option at the end, and it was actually Lewis discipline that said in that limited time I just want to do one run on the prime tyre. He said I know when I put the options on it will be quicker, so I don't need to prove it.

"I spoke to Lewis just now and congratulated it on his discipline because I would probably have tickled him into doing a late run on the option tyre."