While much of the attention was focussed elsewhere, Kimi Raikkonen posted the fastest time on the final day of testing at Spa Francorchamps.
Once again, heavy overnight rain meant that the session got underway on a damp track. However, conditions improved throughout the day, with no further serious rainfall.
Raikkonen continued the work programme begun on Tuesday, which centred mainly on finding the best set-up for the car and the development of new components.
The Finn completed 69 laps on his way to posting a best time of 1:47.042, though this was almost half-a-second off the best time of the week, posted by Lewis Hamilton on Tuesday.
Having had a difficult day on Wednesday, things were slightly smoother for Robert Kubica today, the only driver who has been on duty for all three days of the Spa test.
The Pole did lose some tracktime in the afternoon as a result of a "technical problem", however, he was able to complete 78 laps over the course of the day as he carried out tyre testing and set-up work for the forthcoming races.
The Spaniard completed over 525kms today as he remained focused on set-up development. The dry track running also enabled the team to run some suspension checks, both specific to the Belgian race and the four Grands Prix building up to the event at Spa. The Mercedes engine that had been used for days one and two of the test, was subject to a planned engine change at lunchtime.
Mark Webber finished fourth quickest in the Red Bull, the Australian taking over from David coulthard, who tested here on Tuesday and Wednesday. Unfortunately, the Australian's return to Spa was not a straightforward one as a close encounter with a white line on dry weather tyres on a damp track saw the Australian spin, resulting in damage to front and rear wings. Once repaired, he was back out again on a dry track until an oil cooler problem robbed the team of the last 50 minutes of track time.
"The weather and a couple of mechanical bothers meant that overall, we did not cover the sort of mileage we had been hoping for over the three days," admitted Chief Test Engineer Ian Morgan. "However, on the positive side, we have learnt a lot about a track we had not visited for a while, we completed our tyre comparison programme, as well as trying Bridgestone's rain tyres and we also signed off some new aero and mechanical components for use at next week's European GP."
Giancarlo Fisichella was in the driving seat for Renault. On the basis of the work done by Nelson Piquet and Heikki Kovalainen earlier in the week the Italian progressed further in the team's development programme. Above all, he was out to find his marks on the new Spa-Francorchamps layout and to refine the car's set-up. As conditions improved, Fisichella was also able to test aerodynamic solutions. Despite the variable track conditions the Italian's day went off without a hitch, and by session's end he had completed 76 laps.
"This was an interesting practice session," said the Italian. "It was important to come here and discover the new layout and pursue the team's development programme. I think we've progressed today and the data recorded is encouraging.
"Personally, I love Spa," he added, "and driving here is always a great pleasure. The car handled really well and I was able to get the best out of it in the variable conditions."
"We finished the test with a good day's work," added Christian Silk. "The track was wet this morning and we waited a little before beginning our programme; after that we had a dry circuit which was a great help. Our three drivers have tested the car over the three days and they all say they're happy with its handling. They found it well balanced, predictable and I think that's very positive.
"This test's been pretty encouraging," he continued. "We were not able to complete our programme because of the weather but we were prepared for this and we got through the main items. We now have a lot of date to analyse to be ready for the European Grand Prix."
Alex Wurz took over from Nico Rosberg, the Austrian completing 75 laps and finishing sixth fastest.
"We continued with our set-up preparation work today, while we also ran through some development items," said Dickie Stanford. "Unfortunately, a small technical problem, combined with more poor weather, prevented us from doing the amount of running we would have liked in the afternoon. Overall, it's been a productive test and the boys have all done a really good job for the team."
The changing track surface made comparisons difficult but Jarno Trulli did some running to test tyres in different conditions for Toyota. When the track dried out after lunch he successfully completed a programme that included set-up for the Belgian Grand Prix along with suspension, aerodynamics work and starts.
"It's nice to come back here to Spa because it's the best track in the world," said the Italian. "The organisers have done major work in the paddock and the results look good. The circuit has also been resurfaced and there have been changes to the Bus Stop which have improved the corner. The pit entry and the pit exit are a bit narrow but overall I like what has been done.
"Of course you never know what weather you'll get here and it's always difficult to test in conditions like we saw today," he admitted. "We went out for a few runs on the damp track in the morning but the racing line soon became inconsistent. It was dry in the corners but wet on the straights so that meant it was difficult to carry out much useful comparative work. The track was dry in the afternoon so we were able to run through our programme. We haven't concentrated on lap times but the car felt good. So it's been a positive day and I look forward to coming back for the race."
"Spa is a unique track so the testing we have done this week has been focused firmly on the race here in September," said Pascal Vasselon. "The unsettled weather has been representative of the range of conditions that we could face during the race weekend itself. So we have been very careful to collect data in every single type of weather that we have seen in the last three days. We have also had a wide range of developments to test on the car from suspension to new aero parts. Overall everything has gone well and Jarno and Ralf felt comfortable and quick in the car so they should be well prepared for the Belgian Grand Prix."
Sebastien Bourdais concluded his latest outing with the Toro Rosso team by completing 91 laps, and posting a best time 1.5s off the pace, but better than Honda and Super Aguri.
The STR2 ran trouble free today, which helped the Italian team's pursuit of reliability which has been somewhat lacking in recent races. Other than that the drier weather meant it was time to make up for lost time on the first two days.
"The mixed weather means at least we tried the Bridgestone wets as well as comparing the two types of dry tyre," said Chief Engineer, Laurent Mekies. "Not having been to Spa for two years and this circuit having some unique characteristics, it was very useful to work on defining the aero configuration for this track, in addition to evaluating some new components and brake parts. With neither driver making any mistakes, we were able to do a high mileage over the three days which is good from a reliability point of view."
Takuma Sato was the busiest man today. The Japanese driver completed 99 laps (430 miles) as he worked on achieving a good chassis balance and understanding how the Bridgestone Potenza tyres react to the modified circuit.
"It was a very interesting day," said Sato at the conclusion of the day's programme. "The weather was not consistent; this morning was only damp with light showers later, so we were able to complete a lot of dry running. We concentrated mainly on tyre work and aero analysis, but we also evaluated a new electronics system. There was a lot to do today and we collected a good amount of data.
"The modifications to the circuit are very well done," he added. "There is a new track surface giving it a bit more grip and there is a greater opportunity to overtake and race before the old Bus Stop chicane as you now have to slow down and brake heavily for the revised section. All of the changes seem to be quite safe, although the pitlane entrance is quite narrow. If they look at this before the Grand Prix I think that we will be in for a good race."
Rubens Barrichello took over from Jenson Button, the Brazilian working through an aero evaluation alongside running the two tyre specifications provided by for this event. He finished the day with race start simulations completing 78 laps in total.
"We were able to complete a good number of laps today as the weather stayed fairly dry," said the Brazilian, "and this has provided some useful data on the new aero parts that we ran this week. I had some difficulties with the set-up of the car and the balance is not yet where I would like it to be, however it was a useful test to see how we need to prepare for the race at this circuit."
Honda test driver Christian Klien had his first run with Spyker. The 24-year-old Austrian completed a full day's programme to round-off a productive three-day test for the team.
Klien was the first driver to take to the track this morning. As the circuit dried throughout the day and he gained more experience of the car, he consistently bettered his lap times. He completed 63 laps in total bringing the team's overall test mileage to more than 1,150km as he ran through a programme of evaluation between the hard and medium Bridgestone Potenza tyres, set-up and control and brake system work.
Despite this being his first-ever run in the Ferrari-powered F8-VII, the Austrian recorded a best time of 1:49.119, just 2.4s off the fastest time of the day.
"Obviously it was a new team, new car and a new seat and it took some time to get used to it," said the Austrian, "but there is a good bunch of people here and I felt at home straight away. We did a lot of mileage, but obviously today's focus was to get used to the car and how the engine and gearbox works. I think it all went well, there is potential in the car and I enjoyed the day testing with Spyker. Thanks again to Honda Racing F1 Team for allowing me this opportunity."
"Christian's programme today condensed a lot of work into a short time," added chief race and test engineer Dominic Harlow. "The testing included tyre evaluation, brake system, and control system changes as well as familiarising the driver with the car and systems. The team welcomed the chance to test with Christian; he is a professional and contributed to the day from the start. It was a very interesting day, and apart from a minor technical problem stopping the car on the track for the first time in three days, it was a very productive way to round off the test."