The test would see all three regular drivers Ralf, Juan Pablo, and Marc present during the five days. The aim was to complete what were the system checks of the new car prior to further testing where the team will focus on the performance of the FW25. Surprisingly the new car was not run in its final aerodynamic specification.

WilliamsF1 Chief Operations Engineer, Sam Michael, commented on the test by saying: "It is the end of the first test with the FW25. This week has been about system checks on the car for reliability and performance. Now we head off to Valencia with the test team and a second new car. Juan and Ralf drove the FW25. Marc continued tyre testing for Michelin in the FW24."

The opening day of testing, Saturday 1st February, would see Ralf and Marc carry out the driving duties, with Ralf making a return to testing after his back injury. Both drivers would finish at the bottom of the times for the day, but this is not a surprise considering the teams focus on getting the new FW25 past its first day of testing and complete various systems checks.

Ralf would complete forty two laps but Marc only managed a total of fifteen laps, but achieved the top speed of the day with 293.69 kph. There were no times from the first day of testing.

The second day of the BMW WilliamsF1 Team Catalunya test would again see Marc and Ralf present. The drivers were presented with a chilly start to the day with the temperature moving from four to fifteen degrees Celsius.

Marc would complete eighty five laps, the equivalent of more than 400 kilometres. Ralf also clocked up a high number of laps, with a total of fifty two. Marc's time for the day was the faster one of the two BMW WilliamsF1 Team drivers, with the fastest driver of the day was Toyota's Cristiano da Matta with a 1:17.182.

The next day would see Ralf joined by Juan Pablo with both drivers continuing to put the new FW25 through its early trials. The BMW WilliamsF1 Team had a trouble-free day of testing. The day again would see the team work on the new FW25 and its components so lap times were not of importance.

Ralf and Juan Pablo would complete 104 laps. Again the new car showed very good reliability with no serious problems reported, in particular the P83 engine running well. The team was again satisfied with the performance of their Michelin tyres.

WilliamsF1 Test Team manager Tim Newton commented on the days testing by saying: "Today was the third day running the new car and we are pleased with the progress. The testing programme of a new car involves a lot of routine systems checks as we familiarise ourselves with the new package. Both drivers have been running the FW25, Ralf started this morning while Juan was driving the FW24 - 02 and after lunch, they swapped cars. It is not meaningful at this early stage to estimate likely performance, as there are still areas to be worked on."

The fastest team on the day was that of Ferrari with Rubens Barrichello leading team-mate Michael Schumacher. Monday’s pacesetter Cristiano da Matta was third in the TF103.

The fourth day of testing would see Marc return to replace Ralf, with both drivers continuing to put further kilometres on the car and testing individual components. Gene would complete eighty five laps, though still nearly two seconds slower than the pacesetting Ferraris. Juan Pablo was also off the pace but lap times the team has stressed, are far from top priority in this early development phase. Priority is given to the mechanics of the new car in such an early test of the new FW25.

Again the car proved to be highly reliable. The new BMW P83 engine in particular continued to ran trouble-free. Juan Pablo would complete forty four  laps with his fastest lap time been a 1m:18.909. Team-mate Gené set a time of  1m:17.677. At the top of the times again were the Ferrari pair but Michael Schumacher lead team-mate Rubens Barrichello.

For WilliamsF1 Test team Manager Tim Newton the test sees the team learn more about the new FW25. He said: “It was the penultimate day of this Barcelona test and we had warmer temperatures overnight following yesterday’s frosty start. It remained an overcast day, yet clear and warm. Juan Pablo was running the new FW25 and we continued our evaluation of the new car. We are still learning about its characteristics. Marc was driving in an FW24 and completed tyre tests for Michelin. Tomorrow we will have the same driver line-up.”

The final day of testing for BMW WilliamsF1 Team again saw the team have a trouble free day, with Juan Pablo and Marc focusing on the improvement of various components. At the end of the day Juan Pablo completed seventy one laps with a best time of 1m:16.635. Marc completed seventy four laps with a best time of 1m:17.231.

The team would have another day where the new BMW P83 engine performed well. Dr Mario Theissen, BMW Motorsport Director, commented on the engines performance by saying: "We used Saturday and Sunday for engine development work with Marc Gené driving the FW24D with the new P83 engine fitted. The next three days of the test we were supporting the Michelin tyre development programme which was run with the FW24 and last year's P82 engine. Regarding the new chassis, the FW25, the focus has been on testing the new engine in its final surrounding.

For example checking the cooling system, oil circulation, intake system and exhaust system. This first test confirmed all systems were operating successfully. The next three tests prior to the first Grand Prix will now be focussed on race performance set-up of the whole package."

The BMW WilliamsF1 Team now looks forward to another test at Valencia, 10th – 14th February, where again the FW25 will be put through its paces.

Could any conclusions as to the performance of the new FW25 been drawn. Not really as outright lap times were not yet on the schedule for the team. The focus in these early stages is to check the car for reliability and to examine the consistency of the new chassis and engine.

According to WilliamsF1 Chief Operations Engineer Sam Michael, the development work at the FW25 is progressing nicely. He said: “This car is really no more than a hybrid. It is true that we are further ahead today than where we were at the same time last year.”

Sunday 2nd Feb 2003
Pos. Driver Team/Engine Time Laps

C. da Matta Toyota 1:17.182 56/23
J. Villeneuve BAR Honda 1:18.043 39/38
J. Button BAR Honda 1:18.139 54/30
M. Gené WilliamsF1 BMW 1:18.280 85/79
R. Schumacher WilliamsF1 BMW 1:19.8005 52/17

Monday 3rd Feb 2003
Pos Driver Team/Engine Times Laps

R. Barrichello, Ferrari 1.16.900 64
M. Schumacher, Ferrari 1.17.282 88
C. Da Matta, Toyota 1.17.563 77
J. Trulli, Renault 1.17.778 54
J. Button, BAR-Honda 1.17.826 66
N. Heidfeld, Sauber-Petronas 1.17.907 94
A. Pizzonia, Jaguar 1.18.079 41
J. Villeneuve, BAR-Honda 1.18.342 68
J. Montoya, WilliamsF1 BMW 1.18.511 41
R. Schumacher, WilliamsF1 BMW  1.18.725 62
A. McNish, Renault 1.19.203 64

Tuesday 4th Feb 2003
Driver Team/Engine Time Laps

M Schumacher Ferrari 1:15.454 8/84
R Barrichello Ferrari 1:15.755 52/66
O Panis Toyota 1:17.392 19/55
N Heidfeld Sauber Petronas 1:17.484 28/96
J Trulli Renault 1:17.553 38/54
M Gene WilliamsF1 BMW 1:17.677 43/85
A Pizzonia Jaguar 1:18.057 29/42
A McNish Renault 1:18.449 26/51
J Button BAR Honda 1:18.492 40/43
JP Montoya WilliamsF1 BMW 1:18.909 13/44
J Villeneuve BAR Honda 1:18.978 38/40

Wednesday 5th Feb 2003
Driver Team/Engine Time Laps

M Schumacher Ferrari 1:15.108 13/105
R Barrichello Ferrari 1:15.411 53/54
Heinz H. Frenzten Sauber Petronas 1:16.320 25/111
JP Montoya WilliamsF1 BMW 1:16.635 68/71
O Panis Toyota 1:16. 937 28/62
M Gene WilliamsF1 BMW 1:17.231 8/74
D Coulthard McLaren Mercedes 1:17.297 9/30
K Raikkonen McLaren Mercedes 1:17.976 26/41
M Webber Jaguar 1:18.645 8/27