 Complete the following phrase:   would prove better for both Rosberg and Williams. The Finn had a new teammate in Nigel Mansell and the all carbon fibre Williams FW10 chassis was a big improvement over the FW09B. For the first few races the team used the 1984 engines until Honda introduced an upgraded version which improved power delivery, fuel economy and most importantly, reliability. Rosberg used the new engine to good effect, winning the Detroit Grand Prix and claiming pole in the next two races in 