Pedro de la Rosa topped the timesheets on the third day of testing at Jerez.

With less interruptions from red flags, both the Spaniard and teammate, Alexander Wurz, completed their planned programme, with Pedro covering 77 laps in a MP4-20 fitted with a V10 engine as he focused on tyre comparisons with Michelin.

Alex Wurz put in 70 laps of the circuit in the interim MP4-20B V8, working on engine and set-up development programmes.

Both drivers will be present for the final day of the test at Jerez on Saturday.

Although he finished second quickest overall, and quickest on the V8s, it was a difficult day for Nico Rosberg. The German, who was joined by Mark Webber, suffered an engine failure, and numerous other problems, which seriously reduced his track time.

However, according to Sam Michael: "Today, Nico and Mark concluded the team's test in Jerez, with Nico recording the fastest V8 time on Friday. We've made good progress with all the mechanical components and systems checks on the interim FW27C, while Bridgestone have also moved forward since last week's test in Barcelona.

"On Sunday, we will be running a wet tyre test before returning to a normal programme on Wednesday."

"These initial track tests with the interim FW27C chassis are invaluable to Cosworth in terms of identifying any engine, chassis integration and operational problems," added Simon Corbyn, Head of F1 Race Engineering at Cosworth. "As a result of this week's track running, we've added some jobs to our lists and we're now working through them. We have not yet identified any fundamental engine problems and we're making good progress with the new CA2006 V8 in partnership with WilliamsF1."

English drivers, Jenson Button and Anthony Davidson, were both at the wheel of Honda V8s today, the duo completing a series of tyre and engine evaluations.

"We have had another productive test this week in Jerez completing our full programme," said Button. "I completed 122 laps today without any major issues. We have been focusing on set-up, tyres and the engine, which is looking good. It was encouraging to set the fastest time of the V8 runners yesterday. Everything is going smoothly but we still have a lot of hard work ahead of us and I'm looking forward to the final test of 2005 in Jerez next week."

"It was a good test this week," added Davidson. "We focused mainly on tyre evaluations looking at various casings for Michelin and also on aero performance. Generally the car was quick and the V8 engine proved very reliable with my engine running to over 1100kms."

"We've had some good feedback from the drivers on the improved drivability of the engine since Barcelona and overall the test has been very positive," said Shuhei Nakamoto, Honda Racing Development's engineering director. "We knew that we were testing the limit of the engine that failed and have a countermeasure ready for that, as well as further ideas aimed at increasing power."

Toyota had Jarno Trulli and Ricardo Zonta on duty. The two drivers spent the morning working on set-up before switching to tyre tests for Bridgestone in the afternoon and they got through a lot of laps in a busy day. Both drivers will continue running at the Spanish circuit tomorrow before Ricardo takes part in a Bridgestone wet tyre test on Sunday.

"Ricardo's programme involved basic set-up work on the reference tyres this morning before doing some construction tests for Bridgestone," revealed Mike Gascoyne. "Jarno spent the morning doing set-up and balance work before concentrating on a tyre compound test in the afternoon.

"Ricardo missed out on a bit of running after a fuel system problem but overall this was a constructive day including some useful work with our tyre partner Bridgestone. Our development work with them is already paying dividends even at this early stage of our partnership."

For the most part it was a good day for Jacques Villeneuve, BMW's sole representative. However, in the late morning he suffered a hydraulic leak.

"We had a minor technical problem today," said the Canadian, "but this is something normal with an interim car. We don't expect the car to be very fast, but our long-runs were quite good and we are happy with that. The engine ran well today, too.

"We, the Sauber crew and the people from BMW, were also still about getting used to each other," he added. "However, overall we were making some progress today."

MF1 had Christijan Albers and Tiago Monteiro on duty. They shared the driving duties in both an EJ15B and an interim EJ15B powered by the new Toyota V8 engine. The MF1 Racing team continued the test programme as well as doing some Bridgestone tyre work. Both drivers compared different set-ups and added more mileage to the V8 car.