HKS Intake and Exhaust Systems

HKS's intake and exhaust product lineup is the ultimate embodiment of its "Total Balance Tuning" philosophy. Unlike many aftermarket brands that focus solely on standalone components, HKS develops its intake and exhaust systems as a cohesive, synergistic "breathing system". The goal is to allow the engine to breathe and expel air more efficiently across the entire rev range, rather than merely chasing peak horsepower figures.

Intake Systems: A Full Spectrum from "Mushroom" Pod Filters to Carbon Fibre Airboxes

HKS intake products cover a comprehensive hierarchy from entry-level to high-end setups, with the core objective of reducing intake restriction whilst maintaining or boosting low-end torque through optimised pipework design.

Super Power Flow is HKS's most iconic "mushroom" open-pod intake. Featuring a wet dual-cone cotton gauze filter element mated to a signature red funnel base, it directly replaces the factory airbox. This setup significantly increases high-rev air induction and produces a distinct intake induction roar. Positioned as an entry-level modification, it is relatively wallet-friendly—for instance, the Super Power Flow for the Copen (LA400K) costs around JPY 18,000 (before tax). The drawback, however, is modest heat shielding and limited gains in low-end torque.

Racing Suction is a higher-tier open-pod kit. It typically incorporates a carbon fibre or heat-shielded airbox to isolate engine bay heat soak, along with optimised intake piping. Taking the Racing Suction Full Kit for the R35 GT-R as an example, it comprises the core Racing Suction assembly alongside Premium Suction intake pipes, priced at around RMB 17,600. Beyond just ramping up airflow volume, this kit places greater emphasis on stabilising intake air temperatures (IAT) and preserving low-end torque.

Cold Air Intake is a complete bolt-on kit developed by HKS for modern performance turbocharged machinery (such as the FK8 Civic Type R, GR Supra, and GR86). It features an enclosed dry carbon fibre airbox and full intake piping, extending the intake duct towards the front grille for direct ram-air induction while shielding against engine heat. Its key advantage is delivering denser, colder air, which is immensely beneficial for forced-induction setups. For instance, the Cold Air Intake Full Kit (with AFR adjustment module) for the FK8 retails for roughly RMB 16,500. Do note that certain variants do not come with AFR (Air-Fuel Ratio) recalibration modules, necessitating a proper ECU remap post-installation to prevent triggering a check engine light (CEL).

Additionally, HKS offers the  SUPER AIR FILTER (high-flow drop-in replacement filter) , which installs directly into the stock airbox at an accessible price point (such as a two-piece set for the R35 priced around RMB 770)—ideal for owners keen on retaining the factory intake layout.

Exhaust Systems: An Exhaust Note Hierarchy from Refined Street to Full Race

The HKS exhaust lineup is renowned for its well-defined hierarchy in acoustic profile and performance, with its nomenclature clearly reflecting the intended application.

LEGAMAX Series serves as HKS’s "civilised street" exhaust range. It focuses on improving exhaust scavenging efficiency whilst strictly suppressing in-cabin drone and excessive noise. Both the LEGAMAX Premium and LEGAMAX Sports typically employ high-grade SUS304 stainless steel paired with exquisitely crafted exhaust tips. Taking the LEGAMAX Sports S-Tail for the GR86/BRZ as an example, it features a cat-back setup with burnt titanium-blue tips, delivering a profile that is "sporty yet never obnoxious". For drivers prioritising daily commuting refinement, this remains the go-to option.

Hi-Power Series is HKS’s "high-performance sport" exhaust line. It delivers a throatier note and higher exhaust flow than the LEGAMAX. The Hi-Power SPEC-L II is the headline model here, usually adopting a main pipe plus centre pipe configuration. For instance, the Hi-Power SPEC-L II for the GR Yaris features 50.8 mm piping with 94 mm tailpipe tips, registering a sound pressure level of 85 dB in stationary proximity noise testing. It is ideally suited for fast road cars demanding an aggressive tone alongside tangible performance improvements.

Super Turbo Muffler and SUPERIOR specR represent the upper echelon of the range. The Super Turbo Muffler is engineered specifically for turbo platforms, adopting a straight-through internal layout and dual-layered inner/outer tailpipes with differentiated diameters to slash backpressure while lending a muscular aesthetic to the rear diffuser area. The SUPERIOR specR stands as HKS's flagship pinnacle, fabricated entirely from full titanium alloy in the relentless pursuit of extreme weight reduction, an exotic acoustic pitch, and unmatched visual appeal. Taking the SUPERIOR specR for the R35 GT-R as an example, its price tag is substantially higher than stainless steel alternatives, embodying the zenith of HKS exhaust engineering.

RACING MUFFLER is an uncompromising competition-grade series built specifically for extreme builds producing 1,000 hp and beyond. Dedicated to achieving ultra-low backpressure, it typically dispenses with conventional silencers or retains only a minimal resonator, making it strictly designated for circuit use.

The Core Philosophy: Intake and Exhaust Synergy

The true value of HKS intake and exhaust systems lies in their synergistic engineering. When upgrading to a high-flow intake, excessive exhaust backpressure will throttle induction efficiency; conversely, bolting on a free-flowing exhaust without improving the intake side yields compromised results. HKS's "Total Balance Tuning" ethos delivers harmonised intake and exhaust pairings (such as the Racing Suction matched with the Super Turbo Muffler), allowing drivers to configure a well-balanced "breathing system" tailored to their target power output and driving scenarios—rather than blindly throwing on the loudest or largest aftermarket parts.