Senna questions HRT's third driver call

The Spanish squad hired Klien as third and reserve driver earlier this week and the Austrian will be replacing Karun Chandhok in the first practice session ahead of the Spanish Grand Prix.

But with the team having missed all of winter testing, Senna believes himself and Chandhok need all the track time they can get.

"We have to wait until tomorrow to see if there is any benefit from the experience of the third driver in terms of development of the car, in terms of what direction he can take the team," Senna told reporters in Barcelona on Thursday.

"But in my opinion, because we had no testing at the beginning of the season, the race drivers must do every mile possible. You can see that very few teams are giving mileage to the third driver on Fridays and it's only because they have simulators that the drivers can go there and use.

"I prefer to do as many miles as I can and make sure I can get used to the car before I go to a qualifying session. For me every mile makes a difference. Fortunately I know this track very well, so I know I can pick up pace quite quickly, but we'll see."

The Brazilian said his team will not be introducing any performance updates in this weekend's race, and reckons he will still need to wait some two months before the car gets a significant improvement.

"We haven't got much in terms of performance," he said. "We have some new bits in the car for the suspension and things like this, but they are not really performance-related. They will unlock a little bit of performance but they are more towards the drivability of the car and also control.

"I think it should be better for our consistency and better for the tyres. But in terms of pure performance updates we are a bit short."

He added: "In the end we are still a bit behind in terms of our schedule as well, and what we expect to happen is that maybe in two months' time we get a big update for performance. If you are one or two months late to start then it's pretty normal to be quite late in the development as well."