Toro Rosso were expecting more from 2007

The Ferrari-powered team are, along with rivals Spyker, the only outfit who have not scored any points after the first nine races.

Toro Rosso's season have been marred by reliability issues and accidents, their drivers Scott Speed and Tonio Liuzzi having retired in 13 out of 18 combined race starts so far.

Tost admits they were expecting more from their campaign.

"We still struggle with reliability and I hope we can get this under control from Budapest onwards," Tost said. "We know what our problems are and we have to make some design changes, which is why they cannot happen overnight.

"We also have to improve the performance of the car. Currently we are clearly behind our expectations. The main problem is downforce, particularly at the front end of the car. We will have a new front wing, but it is unlikely to be signed off before Turkey.

"On the mechanical side, we have some good ideas which we hope to incorporate into the car to improve its set-up and therefore its performance."

He added: "We have some very good, very experienced mechanics and for them it was not a problem. However, we also have some less experienced members of the team for whom understanding the car was quite difficult at first.

"But the learning process is over now and everyone understands how it works, how it goes together and how it comes apart. We have no problems in this area.

"Even in the first two races of the season we got three car finishes out of a possible four, which means that our team was up to the job in hand. In subsequent races, we retired because of technical failures, driver errors or collisions with other drivers.

"The team had to move up a step last winter and the job of ensuring the team is operating at its maximum is still not complete.

"We still have a way to go to perform at a level that will allow us to be successful in F1. But we have some very good ideas and I think that by the end of this season we will have made a step forward and by next year we will be much nearer to our goals in terms of how the team operates."

Tost believes, however, that there is still a lot of room for improvement, both from the team and from their drivers.

"They need to improve," said Tost of Speed and Liuzzi. "So far it has been difficult for both of them to get the most out of the car, especially in qualifying. There is room for improvement in every aspect of our team.

"But I believe that our group has potential and we can be successful."