The spectacular Singapore street circuit is regarded as less favourable for the Sauber C31-Ferrari, but the development of this year's car isn't over yet. The team and both drivers, Kamui Kobayashi and Sergio Perez, were pretty busy in free practice trying different components. Kamui also had the springs changed on his C31 in the first session, during which it became dark in Singapore. In the second 90 minutes of free practice at night both drivers worked intensively on the set up of their cars and were using both tyre compounds provided by Pirelli - the soft and the supersoft. Neither driver was happy with the balance of their respective car on Friday. Now the data work begins.

Sergio Perez: "For me it was a difficult day because I was never really happy with the balance of the car. It felt inconsistent and a bit unpredictable. We now have to analyse the data carefully and find a way to improve the car."

Kamui Kobayashi: "The first session when we were evaluating parts was quite positive but in general our performance was rather weak today. I had way too much oversteer. It is great to go racing in Singapore again but it is important that we improve the balance and set-up because you really need confidence in the car here."

Giampaolo Dall'Ara, Head of Track Engineering: "Despite the rain affecting the first session and the red flag affecting the second session massively, we were able to complete our programme. However, the problem is that we are significantly too slow. There seems to be a major problem, but we don't quite understand what it is. We will certainly have a long night analysing all the data. First we have to understand what's wrong, and then we will have to find the right measures to cure it."

Check out our Practice gallery, here.