For the third time in 2015, the teams found themselves testing on the Circuit de Catalunya in Barcelona. This was the fourth test of the year. The test was shorter than the ones in the preseason: only two days in length, compared to four. The same dry and hot conditions from the race on Sunday, carried over to both days of the test. On the positive side, the wind was reportedly lower than it was in the race. The only team that did not make an appearance at the test was Marussia. The formerly bankrupt team said that testing was pointless for them and opted to use the time to prepare for the race in Monaco. Nico Rosberg set the fastest lap time of the test in his Mercedes, with a time of 1:24.374 on day one. Mercedes topped the time charts on day one and setting the fastest time of the test, allowing Nico Rosberg to run 146 laps. Day one was spent setting up the car for the tight streets of Monaco, as well as testing a variety of new parts. Pascal Wehrlein, having to miss the first day of testing for Force India, returned to the track for day two with Mercedes. Much of the morning was spent allowing Wehrlein to get familiar with the car. Near the end of the day, the team was able to run through some practice starts and test some new components to the car. The team completed 137 laps in day two, setting the second fastest time of the day. Pastor Maldonado was behind the wheel of the Lotus for the first day of the test, with the team’s reserve driver, Jolyon Palmer, in the car for day two. Maldonado ran aerodynamics and setup analysis during his 60 laps in the test. His day was hindered by a loss of power, resulting in the replacing of the fuel system. He finished the day in fifth position on the time charts. Palmer was able to set the fastest time of the day after 85 laps. Day two consisted of more aerodynamic and setup analysis for Monaco. There was much work done by the team during the test, but Alan Permane, the Lotus trackside operations director, said: “We’ve plenty to work on back at Enstone before we return to race action next week.” Sauber’s first day of testing went to plan, running Marcus Ericsson in the car. During his 98 laps in the car, he was able to complete the day’s programme that consisted of aerodynamic tests and setup for Monaco. The Sauber car was second fastest in day one. Rafaelle Marciello’s day in the Sauber didn’t go as well as the first. He crashed the car in the first hour and lost much of the morning repairing the damage. Therefore, the team had to abandon the aerodynamic testing that was planned for the morning and had to move onto the setup evaluations for the rest of the day. The team wasn’t able to complete their full programme in day two, after running 75 laps. The Sauber car was the slowest of day two.
Ferrari put Sauber test driver, Raffaele Marciello, in the seat of the SF15-T in day one. The team spent the first day collecting data about their new aerodynamics package. Marciello was shown as third on the day one time charts, having run 125 laps. Team test driver, Esteban Gutiérrez, got behind the wheel of the Italian masterpiece for day two. The team used the final day to continue with aerodynamic research and some setup evaluation. After 118 laps for the day, the team had set a lap time only worthy of seventh in the day. Daniil Kvyat was inside of the Red Bull car for day one. The team had a late start in the morning because the team was working on the gearbox. The day was spent testing aerodynamics and suspension setups. The team also used day one to run some more detailed tests on new components which were fitted to the car for the Spanish Grand Prix. Kvyat completed 101 laps, despite losing a couple of hours early in the session. The car was able to set the fourth fastest time of day one. Pierre Gasly, having tested with Toro Rosso in day one, moving on to the big Red Bull team for day two. He ran 75 laps and set the third fastest time of the day. The team managed to wrap up their programme for the test.
McLaren also had a test driver in the car. Oliver Turvey ran in day one, testing a ton of new components in the day like changes to the rear wing. The team suffered from some issues with the car’s sensors and that caused them to lose a bit of their day. Although the team was the slowest of the day after 66 laps, they were not that far off of the Williams car’s pace. Jenson Button was in the car for 100 laps on the second day. The team spent the session tweaking the front wing and other components of the car. The car’s lap times were just under two seconds faster than they were the day before, claiming fourth on the time charts. Felipe Massa helped the Williams team run some aerodynamic and chassis tests in day one. Some setup work for Monaco was also done. The day was trouble free, allowing the team to run 54 laps. However, the car was second slowest of the day, setting a time slightly faster than the McLaren. The team’s test driver, Alex Lynn, made his Formula One debut on day two. The programme for day two was the same as the previous day. Lynn drove 52 laps and set the fifth fastest time of the day. Force India had Nick Yelloly in the car for day one, replacing an ill Pascal Wehrlein. Yelloly has worked on the team’s simulator program and the main goal of the day was to compare the real car and simulator car, in order to develop a more realistic simulator for drivers. The team also ran a variety of different data collection instruments on the car throughout the day. Despite this being his first time in a Formula One car, Yelloly was able to run 109 laps and gain sixth position on the time charts. Esteban Ocon climbed into the car for the second day. The team set the sixth fastest lap during their 94 lap day of aerodynamic data collection.
GP2 and Red Bull Junior driver, Pierre Gasly, was called up to Toro Rosso for the first day of the test. He ran an impressive 131 laps, during which the team focused on aerodynamic and brake tests. The Toro Rosso was only seventh fastest of the day, but in testing, the lap times are not as important as completing a programme. Carlos Sainz, Jr. took over for the second day of the test, driving 125 laps. The day was spent collecting various data, with some long tyre tests in the afternoon. The lap times for day two were slow, setting the second slowest time of the day, but the team managed to complete the majority of their programme.