The Formula Renault graduate lapped the International circuit in 1m14.289s during three hours of running this morning, pipping Carlin's Oliver Oakes by just 0.019s.
The test marked the first time front running T-Sport team, which ran GP2 Asia race-winner Sergio Perez to four wins and fourth place in British F3 last season, has run the new 2009-spec Volkswagen engine in it's two new Dallaras.
Buzaid reported a significant improvement in performance with the engine, which is some 15kg lighter than the previous spec VW motor.
Buzaid's team-mate, reigning British Formula Ford champion Wayne Boyd, lapped seventh fastest but only 0.153s slower than the Brazilian, while the fastest nine drivers were covered by just 0.329s.
Formula BMW Europe graduate Carlos Huertas continued his recent strong form by going third quickest for Raikkonen Robertson Racing. The Colombian was quickest of all in the final sector of the lap, while team-mate Daisuke Nakajima (younger brother of Williams F1 racer Kazuki) was fastest in the first two sectors, but eighth overall.
Former McLaren Autosport BRDC Award finalist Nick Tandy, who has been second fastest at each of the previous two official tests, struggled to match that form in the new Mygale-Mercedes today and could only manage the ninth fastest time - albeit only just over three tenths of a second shy of the pacesetter.
Pos Driver Team Car Time 1. Adriano Buzaid T-Sport D/V 1m14.289s 2. Oliver Oakes Carlin D/V 1m14.308s 3. Carlos Huertas Double R D/M 1m14.329s 4. Max Chilton Carlin D/V 1m14.330s 5. Daniel Ricciardo Carlin D/V 1m14.346s 6. Henry Arundel Carlin D/V 1m14.381s 7. Wayne Boyd T-Sport D/V 1m14.442s 8. Daisuke Nakajima Double R D/M 1m14.542s 9. Nick Tandy JTR M/M 1m14.618s 10. Walter Grubmuller Hitech D/M 1m15.089s 11. Victor Garcia Fortec D/M 1m15.248s 12. Daniel McKenzie Fortec (N) D/M 1m15.386s 13. Hywel Lloyd CF Racing D/H 1m15.457s 14. Stephane Richelmi Barazi Epsilon D/M 1m15.604s 15. Gabriel Dias T-Sport (N) D/M 1m15.641s 16. Victor Correa Litespeed (N) S/H 1m16.041s 17. Max Snegirev West-Tec (N) D/H 1m16.479s 18. Jay Bridger West-Tec M/H 1m16.761s