On the third day of testing at Bahrain, Kimi Raikkonen continued to dominate with a blistering best time of 1:30.455, a tenth of a second quicker than his best time on Tuesday.
Team-mate Massa managed a best time of 1:21.293 as the pair worked on general development of the F2008, testing out several different setups on the car.
The Toyota pair of Trulli and Kobayashi were also working on the setup and development of their TF108 car. Trulli finished with the third best time of the day with a 1:32.125, and Kobayashi set a best time of 1:32.265.
Both teams will have a two day break before the rest of the F1 teams join them for a further three days of testing.