BMW Sauber say they will not be in a position to challenge McLaren and Ferrari for race victories at the start of the season in Australia on Sunday.
The BMW Sauber car has been unconvincing in pre-season testing
Team boss Mario Theissen insisted the team were determined to win this season but had not yet found the performance.
"Our target is to continue on the steep slope we had in the past two years and to get closer to the two top teams and win a race this year," he said.
"And if you ask me about that, I would say we are not there yet."
BMW Sauber's form in pre-season testing has been unconvincing but Theissen is confident the team are back on the right track.
It is quite clear that we have taken a major step with the new car, one could even say a conceptual step
Mario Theissen (centre)
BMW Sauber team boss
"I don't expect us to be in a position to win a race early on in the season but we still have the target to get there in the course of the season."
Theissen's team finished second in the constructors' championship last season following the disqualification of McLaren, who were found guilty of possessing confidential Ferrari data.
BMW scored almost twice as many points as third-placed Renault but the battle for the minor points positions looks set to be a lot closer this season, with Renault, Williams, Red Bull and Toyota all looking potentially more competitive.
The car had problems when it first appeared but Theissen said the team were getting on top of them.
"The suspension issue was sorted out almost immediately, after the second test we had a solution," stated Theissen.
"The aero situation turned out to be much more complex and it was not one big thing to be resolved but a combination of several steps to be taken.
"All these steps were interdependent, so that's why I said we learned a lot in the past weeks and there is more to come.
"It is quite clear that we have taken a major step with the new car, one could even say a conceptual step.
"You have to take a bigger step and that always means a bigger risk as well. Looking back, I had hoped the car would be quick right away, but we wouldn't do anything different if we had to do it again."