results. For the races in China and Japan, Michael Ammermüller replaced Doornbos as third driver. Spyker MF1 announced a duo of new third drivers for two of the final races of the year. GP2 Series drivers Alexandre Prémat and Ernesto Viso took part in practice in China and Brazil respectively; Adrian Sutil, who had previously tested in Germany and France, again tested for the team in Japan. During the test at the Silverstone Circuit in September, GP2 Series drivers Lewis Hamilton, Nelson Piquet Jr., and Adrián Vallés performed test duties for McLaren, Renault and MF1, respectively. Super Aguri's former race driver Franck Montagny also tested for Toyota. Season calendar The Australian Grand Prix was held later than usual, to avoid a clash with the 2006 Commonwealth Games. For the first time, Bahrain hosted the first Grand Prix. Brazil hosted the last race, while Japan and China swapped their original dates. In 2006, the FIA announced the Belgian Grand Prix would not be part of the 2006 Formula One season, since the local authorities had started major repair work in Spa-Francorchamps. The Belgian Grand Prix returned in 2007, when Kimi Räikkönen took pole position and his 3rd Belgian Grand Prix win in a row. Regulation changes Technical regulations In an attempt to curb the increasing engine power levels of recent years, the maximum engine displacement was reduced from 3.0 to 2.4 litres and the number of cylinders from 10 to 8. At similar engine speeds, the change was expected to cut peak power by around 200 bhp, which would equate to around three to five seconds on lap times at most circuits. (Scuderia Toro Rosso continued to use 3.0-litre 10-cylinder engines with both rev and air-intake limiters to avoid the costs of re-engineering their cars in a short period). Initial testing indicated the new engines were six seconds slower than their V10 counterparts, but early in the season, it became obvious that despite the decrease in power, lap times were not far from 2005 figures; on some circuits, the fastest laps set this year were actually faster than the ones recorded last year, with the V10 engines. Some engine suppliers indicated early that their smaller V8s can rev higher than the 19,000 rpms normal for 2005-spec V10s. Northampton-based engine builder Cosworth had an enviable record of success with V8 engines. It made further history by becoming the first manufacturer to have