Honda RA109E

The Honda RA109E is the Formula One racing engine that Honda, through its F1 programme, developed and built for the 1989 world championship season, the first year the rules banned turbochargers and limited engines to 3.5 litre naturally aspirated units. Honda chose a V10 layout where Ferrari and Lamborghini chose V12s and Ford, Judd and Yamaha chose V8s. Design work began around October 1986 with an 80 degree bank angle that proved troublesome, and the first prototype in July 1987 produced only 430 horsepower, so the bank angle was changed to an evenly firing 72 degrees and the camshaft drive was moved from belts to gears. The finished engine is a water-cooled 72 degree V10 with DOHC and four valves per cylinder, displacing 3,490 cc with a bore and stroke of 91.0 by 53.7 millimetres and giving 685 brake horsepower at 13,000 rpm. It debuted in the McLaren MP4/5 in 1989, the year Alain Prost won the drivers title, and Ayrton Senna won the title in 1990. In 1992 the line passed to Mugen as the MF351H.