Nico Hulkenberg maintained Force India's impressive form to outpace Sauber's Sergio Perez on day two in Spain.
'Hulk' and Perez use super-soft tyres to outpace Vettel
Nico Hulkenberg maintained Force India's impressive start to the Barcelona test by topping the timesheet on day two at the Circuit de Catalunya.
German driver Hulkenberg laid down the gauntlet shortly before the lunch break when he became the first man this winter to venture out on the fastest tyres in Pirelli's range - the red-banded super-softs - and his single flying lap produced a time of 1:22.608.
Sauber's Sergio Perez, who just minutes earlier had gone fastest himself on the soft tyres, swiftly followed Hulkenberg's lead in switching to the super-softs but his next lap came up a mere 0.040s short.
Up until that point and it had been day one pacesetter Sebastian Vettel leading the way - the World Champion's long-time benchmark of 1:23.056s coming on a short run on hard tyres - and while he too improved his time just before lunch, he was on the yellow-striped soft compound and lapped just under three tenths of a second slower than countryman Hulkenberg.
The order at the sharp end largely remained static thereafter as teams again switched to race simulation runs in the warmer afternoon conditions, although Fernando Alonso did make a late dart for the upper echelons of the order with his own short super-soft tyre run, although this was only good enough for fourth.
Ferrari, however, continued to stress that the day had once more been about data acquisition work, with the team also confirming that they were experimenting with different exhaust solutions on the F2012.
Alonso's late move pushed Daniel Ricciardo down to fifth, although this was still something of an impressive position on the timesheet given the Australian's Toro Rosso twice stopped out on the circuit during the day.
The morning session was not even 30 minutes old when his STR7 ground to a halt at turn six, Ricciardo then bringing out Wednesday's only other red flag when the car stopped on the exit of the pitlane with a driveshaft problem just after lunch, which was enough to all-but finish his interest in the day.
Lewis Hamilton took sixth, meanwhile, after going beyond 100 laps for the second consecutive day in the McLaren MP4-27 on what was his final appearance of the week.
The McLaren driver circulated in close company to Vettel for the early stages of their longer afternoon runs, although unlike the German, he more regularly intercepted his stints with visits back to the pit lane.
Nico Rosberg had a relatively low-key first official day in the Mercedes W03, the German appearing to focus on longer runs earlier than most before a transmission oil leak ended his interest after 82 laps.
Williams gave a run-out to their 2012 reserve and Friday driver Valtteri Bottas and the Finn was able to take full advantage of the FW34's apparently rock-solid reliability as he racked up 117 laps.
Another driver making their first track appearance of the year was Vitaly Petrov, the Russian appearing behind the wheel of a Caterham for the first time. Although the team took some time to resolve issues with his seating position and the CT01's brakes early in the day, Petrov was able to complete a total of 69 laps in a best time of 1.26.605.
The testing cast will feature some wholesale changes for the remainder of the week with Vettel, Hamilton and Alonso all making way for respective team-mates Mark Webber, Jenson Button and Felipe Massa.
Day two times:1) Hulkenberg 1:22.608s 112 laps
2) Perez 1:22.648 85
3) Vettel 1:22.891 104
4) Alonso 1:23.180 87
5) Ricciardo 1:23.639 50
6) Hamilton 1:23.806 120
7) Rosberg 1:24.555 82
8) Bottas 1:25.738 117
9) Petrov 1:26.605 69
10) Pic 1:27.343 108
