Speed unsure about Toro Rosso's pace

The Italian squad have introduced new elements in their car following last week's test at Spa, but the American driver said he wasn't sure what effect they have had on the car.

"We have a couple of new parts on the car, but at the moment it is difficult to tell if it has actually done anything or not," said Speed, 19th quickest.

"I did not get so much done and did not complete that many laps after a mechanical problem in the morning. But the car does not feel too bad here.

"It's hard to tell how far off the pace we are as we don't know what fuel loads the others were running. The main problem I had today was a lack of overall grip especially in the first sector and the slow parts."

Speed finished one place ahead of teammate Tonio Liuzzi, who said there is still a lot of work to do in order to be competitive this weekend.

"I had quite a decent day with the car working reasonably well from the morning," said the Italian. "We still have to get a clear picture of how the tyres compare, because we have an idea, but not a completely clear one as yet. The car did not react too badly, but we have plenty of work to do overnight to improve our situation.

"I had a good start to the afternoon session, but towards the end, when I was on new tyres, I lost the rear of the car in corner 5 and went over the gravel on what could have been a strong lap.

"The rain at lunchtime did not have much effect on the track, but the wind changed direction for the second session, which affected corner speed and the behaviour of the car in some corners."