Rubens Barrichello is hoping that an engine upgrade from Cosworth scheduled for the Turkish Grand Prix will help Williams make much needed progress on track this season.
The Brazilian has admitted that he expected more from the Williams-Cosworth package this year following some encouraging performances in winter testing.
However, the team failed to carry that momentum into the season and its best result so far has been Barrichello's eighth place in the Australian Grand Prix.
Barrichello thinks he knows where Williams' problems lie, and has singled out a step forward from Cosworth in terms of driveability and its power characteristics that should help make improvements.
"I was expecting better," said Barrichello ahead of the Spanish Grand Prix. "Testing was a bit vague, and maybe the level of fuel that we had on the car compared to other people might have been a bit different, but the car has not been competitive for some reason.
"It is lacking a bit of grip in low speed, but we have a tendency of losing time in high speed as well. We can do corners flat, but it seems Red Bull Racing has a lot less drag than us so they can keep up speed on the straight.
"Plus we do have some problems with where the power of the engine is. Sometimes with a certain gear ratio it can be quite good but with another one not.
"We didn't graft everything together to show the full potential of the car yet - we have had some good qualifying but we cannot transform that to the race yet."
Cosworth has been working on introducing improvements to its engine, although Barrichello thinks it too early yet to expect a big step forward.
"I think we have to expect Cosworth to perform better during the European season, but it is a bit early now," he said.
"They have obviously done something to improve but it is very minor. What is happening in the background might be good enough for Istanbul so I am hopeful for that race."