[4][5][6] 1989 was the first year where naturally aspirated engines were compulsory for all teams after the banning of the turbocharged units at the end of the previous season.

The following year, these engines were renamed Mugen MF351H and were transferred to the Footwork team, with drivers Aguri Suzuki and Michele Alboreto.

Although Honda withdrew from the sport at the end of 1992 season, Mugen remained affiliated with Footwork in 1993 and created a B version of the MF351H, used by Aguri Suzuki and Derek Warwick.

The team - with drivers Johnny Herbert and Pedro Lamy (later replaced by Alessandro Zanardi) - was underfunded and the 109 chassis was late arriving.

The Mugen engine, codenamed MF351HC (also known as ZA5C), was not able to show its full potential and failed to score a single World Championship point during 1994 despite coming close on 3 occasions.

Gary Anderson would years later reveal that, by that season, Honda's headquarters had increased their involvement in developing the engines that otherwise still carry Mugen branding.

[7] The 1999 season resulted in further success with Heinz-Harald Frentzen winning twice in France and Italy and even challenging for the title, although he failed in doing so due to better performance from McLaren and Ferrari.