The RA series of 3.5-litre and 3.0-litre, naturally-aspirated, V10 racing engines were made by Honda to compete in Formula One racing; between 1989 and 1990, and then again between 2000 and 2005. Between 1992 and 2000, the engines were also made by Mugen Honda. The customer engines were used by McLaren, Arrows, Lotus, Ligier, Tyrrell, Prost, and Jordan.