Team Lotus showed plenty of encouraging signs during Friday's free practice sessions ahead of Sunday's Spanish Grand Prix.

The Hingham-based outfit are hoping their new exhaust and rear-end package will give them an improvement of up to a second over their nearest rivals.

And in two practices, lead drivers Heikki Kovalainen and Jarno Trulli racked up 104 laps as the Norfolk team tried to get to grips with the upgrades for the first time.

'Overall we can be very happy about this Friday,' said Kovalainen, who finished the day less than 0.4 seconds off Paul di Resta's Force India – while the T128's pace on longer runs looked even more promising against those of Toro Rosso and Williams.

'I think we've seen an improvement on where we were and throughout the sessions we could see that we were getting more and more out of the new package.

'The gap to the cars ahead seems reasonably small so I think it's all positive. The key point is that there is a lot more to come out of it.'

Trulli endured more problems with his car's power steering, but caught up on the lap counts in the afternoon: 'For much of the day I didn't really feel like I was getting the most out of it but we have found some of the pace we want to with the updates and with more work there is clearly much more to come.'

Chief technical officer Mike Gascoyne added: 'That was a very interesting and useful day, and good to put so many laps on the new package.

'As we expected the behaviour of the car is now quite different to what we have been working with so far this season and it will take a lot of fine tuning to get the best out of all the improvements, but I think that on the soft tyre and the longer runs we could clearly see some of the improvements we were aiming for.'