BMW Sauber will run a new split-level diffuser at the Turkish Grand Prix in an effort to bounce back from their worst start to a Formula 1 season.
BMW hope the new design will help them improve on a haul of six points from the first six races of the season.
"We will use a multistage diffuser for the first time in Istanbul," confirmed BMW team principal Mario Theissen.
"Nobody in the team expected the season to pan out as it has so far, our results have been quite sobering."
Theissen added: "After taking a forward step in Spain, we were clearly off the pace in Monaco.
Championship leaders Brawn GP, along with Williams and Toyota, had a double-decker diffuser at the start of the season and BMW were among the teams calling for their design to be banned.
The diffuser is an an aerodynamic part at the rear of the car and the split-level design is thought to give an advantage of 0.5 seconds per lap.
BMW Sauber finished third in the 2008 constructers championship but Theissen admits they have been slow to respond to this season's rule changes, although he is confident they can bounce back.
"After three successful years, this phase is our first setback, but we can deal with it, we are all determined to get ourselves back among the frontrunners again."
"To regain our competitiveness we will have to ramp up our development speed significantly. In Istanbul we will have the next step of our development ready."
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