The McLaren MCL32 (originally known as the McLaren MP4-32) is a Formula One racing car designed and constructed by McLaren to compete in the 2017 FIA Formula One World Championship. The car was driven by two-time World Drivers' Champion Fernando Alonso, who stayed with the team for a third season; and Stoffel Vandoorne, who joined the team after Jenson Button retired from full-time competition at the end of the season. Button later returned to replace Alonso for one race and as such, the MCL32 was the last Formula One car raced by the 2009 World Champion. The MCL32 made its competitive début at the 2017 Australian Grand Prix and is the first car built by McLaren since the McLaren M30—which contested part of the season—that does not contain the "MP4" prefix as part of its chassis name. The change was introduced following CEO Ron Dennis's departure from the team's parent company, the McLaren Technology Group, in November 2016. This was the last McLaren car to be fitted with a Honda engine as it was replaced by Renault engines from the 2018 season onwards. After an improvement in the previous year, 2017 was a rough season for McLaren. The cars were slow and the team's Honda engines proved to be very unreliable for much of the beginning of the season. Alonso retired from the opening two races and the team suffered double retirements in China, Monaco, and Italy. The team failed to score a point until Baku, when Alonso finished 9th, with Vandoorne picking up his first point of the season with 10th in Hungary. McLaren finished 9th in the Constructors' Championship, with 30 points, three more than their first season back with Honda power in 2015. The MCL32 was the first McLaren car not to field the British drivers regularly in the McLaren driver's line-up since the McLaren MP4-21 car in 2006 when McLaren paired the Finnish Kimi Räikkönen and Colombian Juan Pablo Montoya as their 2006 season drivers. Montoya was replaced mid-season by Spaniard Pedro de la Rosa. Design and development Power Unit The Fédération Internationale de l'Automobile (FIA) amended the technical regulations for the 2017 season to abandon the token system—which limited engine development over the course of a season—first introduced in , engine supplier Honda was free to extensively redesign the team's power unit, which was named the RA617H. The company started with the ultra-compact RA615H that