HKS Co., Ltd. (株式会社エッチ・ケー・エス, Kabushiki-gaisha Ecchi Kē Esu) is a publicly traded company headquartered in Fujinomiya, Shizuoka Prefecture, Japan specializing in the engineering, manufacturing, and sales of high performance aftermarket and accessory automotive parts and components.

The company began operations by tuning gasoline engines in a dairy-farming shed at the foot of Mount Fuji.

Their goal was to design and build high performance engines and components that major original equipment manufacturers could not, or would not, produce.

[5] In 2010, the official affiliation came to a close and the company was renamed to Kansai Service Co., Ltd. but it still maintains a good working relationship with HKS.

[6][7] In July 1984, HKS built a new factory in Kamiide, Fujinomiya, not far from the site of the original shop at the Mount Fuji dairy-farming shed.

[4][8][9] These technical factories serve as HKS-owned service, tuning, and development centers, as well as offering the sale of select HKS complete vehicles and parts.

[3][11] The HKS headquarters remains near Mount Fuji with its main 100,000 square foot manufacturing and R&D facility[12] in Fujinomiya City, Shizuoka Prefecture with an international sales and distribution network spanning Asia, Europe, Australia and the Americas to support its customer base.

[10][21][22] In 2024, HKS launched a new collaborative brand with Studie AG, a BMW-specific tuning company, named HKSTUDIE.

The company specializes in manufacturing tuning parts for BMW sports cars, such as exhaust systems and coilover suspension.

[23] HKS offers Japanese domestic model cars a wide variety of aftermarket parts ranging from engine internals such as connecting rods and camshafts to external parts such as blowoff valves, intercooler kits, full exhaust systems, turbo kits, engine management systems and other performance electronics.

HKS also manufactures OEM parts to automakers from technologies developed in aftermarket tuning, and even in usage such as marine jets.

[35][36] The Ministry of Land, Infrastructure, Transport and Tourism approved the Shuttle Bus Safety Monitoring Device, named "MAMORU", and HKS released it on March 31, 2023.

[39] Since the 1980s, HKS has competed in many forms of motorsports including time attack, drag racing, JTCC, JGTC, F3, D1 Grand Prix, Superbikes, plus many others.

It produced over 730 ps (720 hp), reached 344 km/h (214 mph), and set a lap time at the Tsukuba Circuit of 1 minute 1.97 seconds.

[47][48] To compete in additional time attack events domestically and internationally, the HKS Racing Performer CT230R was developed in 2006.

The TRB-04 weighed 930 kg (2050 lb) with a stripped body that heavily used carbon fiber, and was powered by a 4G63 MIVEC inline-four engine making 500 ps (492 hp) with an HKS GTIII turbocharger and sequential transmission.

[58][59][60][61] In 1984, HKS supported the FJ20ET engined 'HKS World Trade Silvia S12' competing in the JSS (Japan Super Sports) championship with driver Seiichi Sodeyama.

[62] HKS participated in the 1986 Grand Champion Series with an original 2000cc DOHC 4 cylinder 5 valve engine called the "186E", based on the BMW M12.

[3] In the early 1990s, HKS undertook a Formula One engine development program, to hopefully produce a motor in-house for use in F1 race cars.

[3] In the inaugural D1 Grand Prix drifting series in 2001, the HKS-sponsored Team After Fire Nissan S15 Silvia won the championship, driven by Nobuteru Taniguchi.

[79] In 2002, the HKS works team officially entered with a S15 Silvia, winning the 2nd round, and finishing as the runner-up for the season championship.

[81][82] The HKS team entered a modified Toyota Altezza entitled the "Racing Performer IS220R" in the 2004 series, won the 4th round and finishing in 2nd place as the championship runner-up.

[101][102] HKS tuned cars and aftermarket parts have been featured in video game series such as Need for Speed, Gran Turismo, Forza, Midnight Club, Street Racing Syndicate, and Juiced, and cars with HKS liveries and tuning have been featured in the Fast and the Furious movie series.