Adrian Sutil has admitted that Sauber is simply too slow ahead of this weekend's Chinese Grand Prix.
Neither Sutil nor team-mate Esteban Gutierrez has scored a point so far in 2014, while their last two events have been blighted by unreliability and accidents.
The German reckons Sauber made progress with the C33 at last week's post-race test in Bahrain but does not believe the team will make huge improvements until the sport reconvenes in Europe next month.
"A little progress has been made at the test with the test drivers in Bahrain, so it was quite conclusive," he said. Of course at the moment we are far too slow. Not really enjoyable but we are looking ahead. It will get better. It’s just a question of time. We need to be a bit patient. So, for here, there are a few things changed already.
"So, I’m quite excited to see how the car will be. But our plan, especially for the next races going to Europe and going to Barcelona and on, the car should definitely be a different one to drive."
Sutil says that there is not one key weakness restricting Sauber from making progress.
"It’s not only one area, quite a few areas of the car," he said. "It’s the power unit, it’s the weight - and I’m fighting also personally a little bit here and there. It will get there and as soon as we do progress every race weekend, I’m happy. Fingers crossed it’s going to happen very soon."