Christian Klien topped the timesheets on the second day of testing at Jerez, as McLaren, Renault, Toyota, Red Bull and Toro Rosso joined the three teams who began testing here on Tuesday.

Once again, some of the teams had an eye on next season, in addition to preparing for the last four races of this year.

Pace-setter Klien worked on the mechanical set-up of the F1.08, also testing various aerodynamic settings in readiness for the remaining races of 2008. The Austrian completed a total of 84 laps on his way to posting a best time of 1:19.357.

"A whole day's testing without any problems gave me the opportunity to provide the engineers with a lot of feedback on new components," said Klien. "The new surface on parts of the track provides better grip, and has smoothed out the bumps that were there before."

Robert Kubica was scheduled to take over tomorrow. However, due to an infected tooth he has had to cancel his trip to Jerez at short notice. Therefore, Nick Heidfeld is scheduled to take over testing duties for the remaining two days.

Second quickest was Monza hero Sebastian Vettel. However, unlike last Sunday, when he drove the Toro Rosso, today he was in the Red Bull, in anticipation of his switch to the Austrian outfit next season.

Set-up work was the main item on the agenda for the German youngster, as the team gets to know him and vice versa. Other work included data acquisition from a few new components. Despite losing some track time in the afternoon with a gearbox problem, Vettel completed 60 laps in total, setting the second best time of the day. Hel continues testing with Red Bull tomorrow, before switching back to Toro Rosso for the final day.

As it happens, third quickest was the Red Bull, with Sebastian Buemi at the wheel, one of several drivers under consideration for a 2009 seat.

After a delayed start, due to an unspecified mechanical problem, Buemi carried out some aero configuration work and general set-up, completing one long run at the end of the day.

According to the team, the Swiss driver made no mistakes and provided good feedback throughout the day. "I'm quite happy, it was a very good first day and I really want to thank Red Bull for the opportunity to test the car," said Buemi.

Tomorrow, driving duties will be carried out by Takuma Sato, another 2009 hopeful.

Gary Paffett was in action for McLaren, as the test team kicked off its final full session of the season. The English driver's programme included front-end aerodynamic development and set-up work for the remaining four fly-away Grands Prix.

In addition, the team started the on-track evaluation of its KERS system. The process will include a range of steps, which is initially focused on vibration and housing checks with the system in a passive mode.

Kamui Kobayashi was at the helm for Toyota, spending the day focusing on preparations for next week's Singapore Grand Prix, running in a high-downforce configuration while carrying out work on brakes and other systems. He had a trouble-free day completing nearly 94 laps. The Japanese youngster will remain at wheel tomorrow.