Bruno Senna plays down Williams's slow times on day two of Mugello Formula 1 test

Senna ended the second day at the bottom of the timesheets, his best of 1m24.842s more than three seconds adrift of Romain Grosjean's benchmark time for Lotus. However, the Brazilian put the time down to "boring" development work, rather than an actual lack of pace.

"It was a long day," he said. "We tried a million parts in the car, and all of these parts needed validation, so we tried exactly the same thing, with procedures.

"The morning was very boring, but it was important to get it out of the way, and fortunately the day was good in terms of weather so we got some good information.

"You always want to be in the top part of the times, but you don't know what everyone else is doing in the field, and this is a track that if you take some fuel out of the car, the lap-time comes big time. It was more important for us to know where we are than do a lap-time."

On the back of the test, Senna is expecting a raft of small changes to be made to the FW34 before next week's Spanish Grand Prix.

"It's a never ending upgrade game in Formula 1," he added.

"What we're trying here will probably show up in Barcelona. It's always improving and getting better, and I think other guys are finding some good things in their cars so we need to keep it up and keep pushing.

"It's always going to be an evolution. Learning from what we've brought, some things have had the right reaction, and some things haven't quite got the results that were expected. There is a lot of data to go through and [the team] are having some late nights, they are pushing very hard to understand what the performance is and bring the good bits to Barcelona and onwards."