HKS: The Tuner That Built the Japanese Aftermarket From Turbochargers Up

HKS (Hasegawa Kigyo Sha, roughly "Hasegawa Corporation") is the single most important Japanese aftermarket company in automotive history. Founded in 1973 by Hiroyuki Hasegawa — a Yamaha Motor engineer who left to start his own company — HKS pioneered virtually every category of performance parts that define the Japanese tuning scene today: bolt-on turbocharger kits, boost controllers, blow-off valves, piggyback ECUs, and metal head gaskets.

If you've ever modified a Japanese turbocharged car, you've almost certainly owned an HKS product. This is the story of the company that turned Japanese tuning from a garage hobby into a multi-billion-dollar global industry.

The Origin Story

Hiroyuki Hasegawa was a Yamaha Motor engineer in the late 1960s and early 1970s, working on two-stroke motorcycle engines. He was obsessed with the idea of turbocharging — at the time, turbos were exotic, expensive, and almost exclusively found in diesel trucks. But Hasegawa saw potential for forced induction in gasoline performance cars.

In 1973, he left Yamaha to start his own company with two colleagues, Goichi Kitagawa and Sigma Automotive. The company was initially called "HKS" — a combination of the founders' surname initials: Hasegawa, Kitagawa, and Sigma. They set up shop in Sagara, Shizuoka Prefecture (at the base of Mount Fuji), where HKS headquarters remain today.

Their first product, released in 1974, was the world's first bolt-on aftermarket turbocharger kit for a passenger car — specifically, the Nissan Fairlady Z (S30). The kit produced 11 psi of boost and added approximately 50% to the Z's factory power output. It was expensive, it was hard to install, and it sold out immediately. HKS had found its niche.

The 1980s: Building the Aftermarket

Throughout the 1980s, HKS systematically invented or popularized most of the parts that tuners today take for granted:

• 1981: First aftermarket blow-off valve (BOV). The familiar "pshhhhh" sound of a venting BOV was originally an HKS sound signature.
• 1983: First aftermarket boost controller. The HKS EVC (Electronic Valve Controller) was the first electronic boost controller on the market, replacing the janky mechanical bleed valves tuners had been using.
• 1985: First aftermarket metal head gasket. Originally designed for the Nissan L-series, it expanded to cover every Japanese turbo engine.
• 1987: First turbocharger with ball bearings designed for aftermarket use.
• 1989: HKS Racing Suspension launch — coilovers with separate adjustable damping.

By 1990, HKS had gone from a three-person startup to a 400-employee company with international distribution. Their blue-and-silver logo was everywhere in magazine advertisements, at racing events, and on the dashes of tuned Japanese cars.

The Drag 7: The Car That Made HKS Famous

In 1991, HKS built a modified Toyota Supra MK4 called the Drag 7 — a drag-only build designed to showcase their turbocharger technology. The car ran a fully-built 2JZ-GTE with a GT4202R turbocharger (HKS's own development), nitrous, and methanol injection. In 1996, the Drag 7 ran a 7.67-second quarter mile at 184 mph — an all-time record for a Japanese drag car at the time. The video of the run circulated in the early internet tuning forums and made HKS a household name among car enthusiasts worldwide.

The Drag 7 and its successor, the Drag 8, set multiple drag records through the 1990s. The engines in these cars eventually exceeded 1,200 HP — at a time when very few tuners were making even 700 HP from a Japanese engine.

Signature Products

HKS GT-RS and GT3037S Turbochargers

HKS developed their own line of turbochargers in the 1990s and 2000s. The GT-RS (a dual ball-bearing turbo with a 57-trim compressor) and the GT3037S (a larger frame ball-bearing turbo) became the default upgrade turbos for Skyline GT-R and Supra builds. While these have since been eclipsed by Garrett GTX and Precision turbos, they defined an era.

HKS F-Con V Pro

HKS's standalone piggyback/standalone ECU. The F-Con was one of the first user-friendly tuner ECUs and became the go-to for 1990s tuners. It's still manufactured today (F-Con V Pro 3.24) and remains popular for tuning Japanese engines.

HKS SQV Blow-Off Valve

The iconic HKS Sequential Blow-Off Valve. Chrome-plated, loud, and visually distinctive. The SQV became a rite of passage for tuners in the 2000s — if you had an HKS SQV on your car, you were serious.

HKS Hipermax Coilovers

Mid-range to premium coilovers that balance streetability with performance. The Hipermax IV line remains popular for street-driven GT-Rs and Supras.

HKS Legamax Exhaust Systems

Cat-back and full turbo-back exhaust systems. The HKS Legamax became a signature sound for modified Japanese cars in the 2000s.

Motorsport Involvement

HKS has competed in:

• Super GT (JGTC) — Running their own race team from 1993 through 2007, competing with modified Toyota Supras, then NSX-R, then Honda NSX-GT.
• Rally Japan — HKS-backed Lancer Evolutions in the All-Japan Rally Championship.
• Time Attack — HKS-prepared cars have won or placed in Time Attack events worldwide, including multiple appearances at Tsukuba and Suzuka.
• Drag racing — The Drag 7 and 8 are the most famous, but HKS continues to develop drag race cars.

HKS Today

Despite the gradual decline of the JDM tuning scene from its 1990s peak, HKS remains one of the largest aftermarket performance companies in the world. Annual revenue exceeds $100 million USD. Products are distributed in over 60 countries. Their catalog now includes parts for Subaru, Mazda, Honda, Toyota, Nissan, Mitsubishi, and increasingly, European and American cars (BMW M-series, Mustang GT, etc.).

HKS also operates their own HKS Circuit — a private test track in Sagara where they develop and dyno-test their products. Visits to the HKS headquarters are considered a pilgrimage for serious Japanese tuning enthusiasts.

Why HKS Matters

HKS didn't just sell parts. They built an entire industry. Before HKS, Japanese tuning was a hobby for garage mechanics and rally mechanics. After HKS, it was a profession, a career, and a global movement. Every other major Japanese tuner — Nismo, Greddy, Apex'i, Tomei, Blitz — followed HKS's lead. The playbook of "design your own turbochargers, publish records, build halo cars, sell to the masses" was HKS's invention.

Today, when you see a Supra with an HKS turbo manifold, a blow-off valve venting atmospheric boost, and an HKS F-Con Pro ECU, you're looking at 50 years of continuous innovation that started with one Yamaha engineer who thought turbochargers belonged in street cars. Hiroyuki Hasegawa was right. And HKS has been reminding us ever since.