The situation improved immensely when Ayrton Senna signed to partner Alain Prost (at Prost's suggestion) on a 3-year contract. The McLaren chassis, the Senna and Prost pairing, and finally the new Honda engines with , looked like a formidable combination. However, there were concerns after the FIA introduced a fuel regulation for the turbo-powered cars of 150 litres for a race distance. Honda's engine management team worked feverishly on the fuel consumption of the RA168E which was specially built for the reduction in turbo boost from 4.0 bar to 2.5 bar rather than upgrading the 1987 spec engine, trying to improve it in order to avoid embarrassing late-race retirements. The car appeared 'as-is' through the season, save for a few aerodynamic revisions. The car arrived at the first race in Brazil with very little pre-season testing at Imola only a week before the race, but Senna was able to put the car on pole position by half a second from surprise 2nd placed qualifier, Nigel Mansell driving the , naturally aspirated Williams-Judd V8, with Prost qualifying 3rd.