Lotus driver Romain Grosjean set the fastest time in Formula One testing for the second successive day on Friday, clocking a best lap of 1min 22.614sec.
Grosjean's French compatriot Jean-Eric Vergne, who had topped the time charts with 1min 23.614 in the Toro Rosso in the morning session, finished the day as second overall fatest.
World champion Sebastian Vettel, in the Red Bull, was third, ahead of Ferrari's Fernando Alonso.
Vettel said that some new parts will be added to the Red Bull for the final two days of testing.
"We have some new bits for the next two days and then we'll know a little bit more," he told www.autosport.com.
"Everyone is a bit in the same situation. Usually the last couple of days of testing are quite important because you bring some new bits and the car is closer to what you will race at the first race, so we will see if that comes true.
"Hopefully we can make another small step forward and then we should be okay."
Testing continues until Sunday ahead of the first race of the 2012 Formula One season in Melbourne, Australia, on March 18.
Another former world champion Lewis Hamilton was down in ninth in his McLaren, but was adamant that the team had collected crucial information.
"Today was all about testing set-up. It was a good day: we learned quite a lot and improved a few things. We didn't get a lot of mileage, as we had a lot of downtime in between changes," said Hamilton.
"Our car feels better set-up wise, we still haven't added the new aero package, so I think we'll get a better picture of what the car will be like in Australia over the next two days. But I definitely feel like we have a competitive car.
"This year's winter testing has been way better than last year. I've not had any problems, we've ironed out a lot of issues and I feel very comfortable. I'm fit and ready for Melbourne."
1. Romain Grosjean (FRA/Lotus-Renault) 1:22.614 (124 laps), 2. Jean-Eric Vergne (FRA/Toro Rosso-Ferrari) 1:23.126 (45), 3. Sebastian Vettel (GER/Red Bull-Renault) 1:23.361 (85), 4. Fernando Alonso (ESP/Ferrari) 1:23.447 (125), 5. Heikko Kovalainen (FIN/Caterham-Renault) 1:23.828 (104), 6. Kamui Kobayashi (JPN/Sauber-Ferrari) 1:23.836 (77), 7. Nico Hulkenberg (GER/Force India-Mercedes) 1:23.893 (36), 8. Michael Schumacher (GER/Mercedes-AMG) 1:23.978 (79), 9. Lewis Hamilton (GBR/McLaren-Mercedes) 1:24.111 (65), 10. Bruno Senna (BRA/Williams-Renault) 1:24.925 (48), 11. Pastor Maldonado (VEN/Williams-Renault) 1:25.801 (20)