Single-seaters

Working with Honda, Mugen has gradually expanded its sporting involvement to all levels of the sport. In 1986, Formula 3000 was introduced into Japan and Mugen joined forces with Honda to build an F3000 engine. It was introduced in the 1987 season and leased to 14 teams. The following year, Mugen won four of the top five places in the Japanese F3000 championship. In 1989, Mugen entered European F3000 with the MF308 engine and won the championship with Jean Alesi, driving an Eddie Jordan Racing Reynard. The same year the company produced its own prototype 3.5L  V8 Formula One engine, codenamed MF350.

In 1988, Mugen started tuning Honda engines for use in Formula Three, winning the Japanese series with Akihiko Nakaya, and in 1990 expanded their business to Europe. The same year, Mugen won its first Formula Three championships in Europe, taking the French title with Éric Hélary, and the British crown with Mika Häkkinen at the wheel of a West Surrey Racing Ralt, which repeated the title in 1991 with Rubens Barrichello.

As F3000 became a spec-series in Europe starting in 1996 with the Lola-Judd combo, the Japanese series responded by making Mugen the sole supplier to the Japanese championship, now redubbed Formula Nippon. M-TEC lost the supply contract for the 2006 season, with the rules changing to allow Toyota associate TOM'S to join Mugen as engine supplier.

Mugen continues to enjoy success in the Formula Three circuit with its tuned 2.0 L Honda engines, having won 9 titles in Asia (8 of which in Japan) since 1988, as well as 19 titles in Europe (15 of them in Britain), and 13 in Latin America.

As of 2017, Mugen Formula engines still enjoy use and success across the various European hillclimb championships, employed in former Formula chassis and dedicated hillclimb prototypes.

Formula One

In 1991 Mugen prepared Honda V10 engines for Tyrrell (based on engines used by McLaren in 1989 and 1990), but 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.

At the end of the year, Mugen switched to Team Lotus with plans for a new Lotus 109. 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. This was the only season in which Mugen engines (and Lotus) did not score a World Championship point during their time in Formula One.

After Lotus closed at the end of the year, Mugen switched to the Ligier team, which was then being run for Flavio Briatore by Tom Walkinshaw, with drivers Olivier Panis, Martin Brundle and Aguri Suzuki, although it was initially planned for the Minardi team. The 3.0 L engine, conforming to the new regulations, was codenamed MF301H. The 1995 season was promising with points being scored at nine races and the team securing two podiums, one courtesy of Brundle finishing third at the Belgian Grand Prix and the other by Panis finishing second at the Australian Grand Prix. The team secured 24 points and finished a respectable 5th in the Constructors Championship. The following season with Ligier resulted in Mugen's first Formula One victory as well as Ligier's last Formula One victory at the 1996 Monaco Grand Prix with Panis at the wheel. Despite this unexpected success, the Mugen powered Ligier car only scored three more points finishes during the rest of the season two 6th-place finishes from Diniz and one 5th-place finish from Panis; the team suffered 17 retirements during 1996.

Ligier was taken over by Alain Prost in 1997, and the newly named Prost Grand Prix ran MF301HB engines with Jarno Trulli leading the Austrian Grand Prix before suffering an engine failure. The Prost team managed two podium finishes during the 1997 season at Brazil and Spain, scoring points in 8 races over the season securing a final total of 21 points and a 6th-place finish in the Constructors Championship.

With Prost establishing a relationship with Peugeot and switching to them from 1998 onwards, Mugen looked for a new partner and reached a two-year agreement with Jordan Grand Prix for which Mugen produced the MF301HC engine. The first half of the 1998 season was an absolute disaster; it was so bad that at one point Mugen officials met with Eddie Jordan and his team during the 1998 Monaco Grand Prix to find out why up until then the team had failed to score a single World Championship point.^{[citation needed]} The relationship continued at Silverstone where the team scored their first World Championship point of the season courtesy of a 6th-place finish from Ralf Schumacher, followed by points finishes at the next 3 races. It was not until Spa-Francorchamps, when Jordan's fortunes changed for the better with drivers Damon Hill and Ralf Schumacher scored a 1–2 finish securing Jordan's first ever Formula One victory and their only 1–2 finish during their existence after a crash-marred start. The team would score points on two further occasions with Ralf achieving a 3rd-place finish at the Italian Grand Prix. Gary Anderson would later reveal that, by that season, Honda's headquarters had increased their involvement in developing the engines that otherwise still carry Mugen branding.^[5]

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. After Honda returned to the sport from 2000 with British American Racing, Mugen left Formula One after another year of having both Honda and Mugen engines racing together, leaving Honda to supply the engines to Jordan as well in 2001 and 2002. Mugen-built engines were also used for the RC101B/RC-F1 2.0X, a car built by the Honda R&D Center without direct support from Honda headquarters (previous cars built by the R&D Center used older Honda engines when they supplied engines for McLaren) and for the Honda RA099, an official Honda test car to prepare for Honda's factory engine supply operation.

Sportscar racing

In 1998, Mugen built four NSX models, two for the Mugen/Dome partnership, one for Team Kunimitsu and one for Nakajima Racing. The cars were fast but unreliable at first, until the Nakajima NSX scored the car's first win at the fourth round in Fuji. This was followed by three more wins (one of them by the Mugen/Dome team), which led to a second place championship finish for Tom Coronel and Kouji Yamanishi. In 1999, the Honda took three more wins, one of those with the Mugen/Dome team of Juichi Wakisaka and Katsutomo Kaneishi scoring a victory at the opening round in Suzuka and finishing the third best team in the championship. In 2000, the Mugen/Dome team was champion with Ryo Michigami, but the car's performance was limited by regulation changes and Michigami reached the title without a single win. Still, Honda won four races, one of them by the second Mugen/Dome car.

In 2001, Mugen concentrated once more in the JGTC, the NSX winning two races, and finishing second (Mugen/Dome) and third (ARTA) in the series. More importantly, in June, the company announced development of a new 4.0 L V8, dubbed MF408S, for the main prototype class in the 24 Hours of Le Mans and American Le Mans Series. At the time, Mugen acknowledged that international sportscar racing was a new category for them. The concept of the MF408S was high power, compact size, durability and reliability. Mugen chose a 4.0 L (N/A) Naturally aspirated engine because they felt through their experience in Formula Three that restrictor size was key to performance. The idea was to save fuel with a smaller displacement engine, since, theoretically, restrictor size will bring power in any engine to a similar level. The main engines in use at the time were producing around 600 hp, including the turbocharged Audi and Cadillac, as well as the larger displacement BMW and the Roush-prepared Ford. Mugen excluded a turbo as this necessitated use of intercoolers to extract maximum performance, which added to the weight and reduced performance.

2002 was a good year for Mugen at the track. The Mugen-prepared NSXs won five rounds, with the Mugen/Dome team winning two races outright, which gave them the Team's championship title. The debut of the MF408S was in a Panoz chassis in the 2002 Sebring 12 Hours, first round of ALMS.

In 2004, M-TEC decided to drop down to GT300 and help train Japanese drivers for GT500 speeds. By grabbing promising drivers early in their careers, M-TEC would then be able to mold them and have definite access to future champions. M-TEC driver, Hiroyuki Yagi, was sourced from the Integra Series. Giving the drivers experience was more important than developing the car to take the championship. To this end, M-TEC simply detuned the car for the GT300 class without optimizing it for the new power level. Winning the GT300 series by one point over the ARTA Garaiya was simply an unintended bonus for a dedicated, championship-level team.

Breaking into the United States is another goal for the M-TEC team and the Mugen name. Currently, the authorized dealer of Mugen parts in the US is King Motorsports. Team director Junichi Kumakura thought racing the NSX in the United States was a great way to promote the company in a previously unvisited environment. When asked what else M-TEC would like to accomplish in America with the golden NSX, competing at Sebring and Daytona were marked as attractive goals.

Motorcycle Racing

List of Mugen vehicles

• Honda City Turbo I and II
• 1984 Mugen Honda CR-X
• 1991-1996 Mugen Honda Beat
• 1992-1995 Honda Civic SiR I and II Mugen (hatchback model and sedan model)
• 1996-2001 Honda Integra Type-R Mugen
• 1994-1997 Acura/Honda Integra Mugen (bugeye version)
• 1997 Mugen CRX Del Sol
• 2000 Honda Prelude
• Dc5 Honda Integra
• 1996-2000 Honda Civic SiR Mugen hatchback coupe and sedan model
• 2004 Honda Fit Dynamite
• 2005 Honda Legend Max
• 2006 Honda Fit Spec.D
• 2006 Honda Civic Dominator
• the Road to Racing Concept (Honda Civic-based) (2007)
• Open-Top Pure Sports Concept (Honda S2000-based) (2007)
• Mugen Courage LC70 (Japan Le Mans Challenge LMP-1) (2007)
• Mugen S2000 (2008)
• Honda Fit F154SC (2008)^[9]
• Mugen RR Experimental Spec. (Honda Civic Type R-based) (2008)
• Honda Civic 5D MUGEN^[10][11] (2008)
• Honda NSX Mugen RR (2009)
• Honda Civic Mugen RR Advanced Concept (2009)
• Honda Accord Mugen 24sc (2009)
• Honda Odyssey Mugen (2009)
• Honda Insight ZE2 (Mugen Zero-Lift) (2010)
• Honda CR-Z: RR Concept (2012)
• Honda CBR1000RR
• Honda City ZX 2009

Production vehicles

• 2008 Civic Mugen Si marketed in North America
• 2007 Civic Mugen RR marketed in Japan
• CR-Z Mugen
• Accord Mugen