GR86 & BRZ Supercharger Install Guide: HKS GT2 FA24

Supercharging a 2022-2024 GR86 or BRZ is the single biggest power upgrade you can bolt onto the FA24 flat-four, and the HKS GT2 S/C System is the kit that makes it a weekend job instead of a science project. Stock, the 2.4L boxer makes 228 hp at 7,000 rpm and 184 lb-ft at 3,700 rpm — strong for a naturally aspirated four, but the chassis is begging for more. Add the HKS GT2 centrifugal supercharger and HKS rates the FA24 at 297 PS (roughly 293 hp), a jump of 56 PS, with properly tuned cars regularly showing 280-300 whp on the dyno. This step-by-step guide covers how the kit works, how it installs, and the supporting mods every supercharged GR86 and BRZ needs.

Why the FA24 GR86 & BRZ Is Built for a Supercharger

The second-generation GR86 and BRZ share Subaru's FA24D, a 2.4-liter naturally aspirated flat-four that replaced the old 2.0L FA20. It makes 228 hp and 184 lb-ft on premium fuel, runs a high 12.5:1 compression ratio, and uses Toyota's D-4S port-and-direct injection. That extra 400cc over the first-gen car cured the infamous mid-range torque dip, but the FA24 is still an NA engine that runs out of breath near its 7,500 rpm redline. A 6.1-second 0-60 mph time is quick for the money, yet owners chasing 300+ whp quickly hit the wall of what cams, headers, and tunes can deliver on an atmospheric engine.

Forced induction is the answer, and a centrifugal supercharger suits the FA24 particularly well. The high 12.5:1 compression means the engine responds hard to even modest boost, so the HKS GT2 kit only needs roughly 7-9 psi at the standard pulley ratio to add 60-90 wheel horsepower. Because a centrifugal blower builds boost with rpm, the supercharged FA24 keeps the linear, high-revving character that makes the GR86 and BRZ fun — it just does it with a much fatter torque curve underneath. At NLP Performance in Tampa, FL, the supercharged FA24 is one of the most-requested builds we spec, precisely because the platform tolerates boost so gracefully.

How the HKS GT2 Supercharger Works on the FA24

The HKS GT2 S/C System is a complete, vehicle-specific centrifugal supercharger kit built around the GT2-7040L blower. A centrifugal supercharger is a belt-driven compressor that looks and behaves like the compressor side of a turbocharger, spinning an impeller to pressurize intake air — but it is driven off the crankshaft instead of exhaust gas, so it makes clean, predictable boost that climbs with engine speed. HKS enlarged the GT2 head unit's rotor for the 2.4L FA24 versus the older FA20 version, matching the blower to the bigger engine so it makes usable boost without over-spinning.

Crucially, this is a "complete kit," not a bare blower. HKS includes the GT2-7040L supercharger, an air-to-air intercooler to drop charge temps, all mounting brackets and hard piping, and the special traction fluid the GT2 unit uses. The layout reuses the factory airbox to keep intake temperatures and noise in check, and it is engineered to minimize cutting and permanent modification. HKS designed the kit for around 7-9 psi at the standard pulley, which is why the naturally aspirated 12.5:1 FA24 can safely accept it with the right calibration — and why professional ECU tuning (HKS recommends its F-CON iS controller) is the single most important part of the install.

How to Install the HKS GT2 Kit: Step by Step

A GT2 supercharger install on a GR86 or BRZ is a full weekend job for an experienced DIY builder and a one-to-two-day job in a professional shop. Budget 12-16 labor hours. Below is the workflow we follow at our Tampa install bay; always follow the current HKS instruction manual for torque specs and hardware, as it supersedes any general guide.

Step 1: Baseline, Prep, and Fuel

Start with a healthy engine and a baseline dyno pull. A supercharger multiplies whatever the engine already is, so confirm compression and fix any oil consumption before adding boost. Change to fresh, high-quality oil and verify the cooling system is in top shape. Decide your fuel strategy up front: the GT2 kit is tuned for 91-93 octane pump gas at standard boost, but many owners run ethanol blends for extra safety margin and power — that choice drives your tune and whether you need upgraded fueling.

Step 2: Mount the Supercharger, Intercooler, and Piping

With the front bumper and factory intake removed, bolt the GT2-7040L head unit to its HKS bracket, then route the drive belt off the crank pulley. Mount the air-to-air intercooler in the front airstream and run the supplied hard piping from the blower discharge through the intercooler and into the throttle body. Reconnect the factory airbox as the blower's inlet. Because HKS ships matched brackets and pre-bent piping, this stage is mostly bolt-on, but take your time getting belt alignment and piping clamps perfect — a thrown belt or a blown coupler at 8 psi ends a dyno day fast.

Step 3: ECU Calibration and Break-In

Never start a supercharged FA24 on the stock tune. The ECU must be recalibrated for the new airflow, boost, and fuel demand — HKS designed the kit around its F-CON iS piggyback controller, and dyno tuning on a load-bearing dynamometer is where the 297 PS actually shows up. A calibrator will dial in fuel and ignition across the rpm band, set safe knock thresholds for the 12.5:1 engine, and verify air-fuel ratios under boost. After tuning, follow a gentle break-in: keep boost light for the first 300-500 miles, recheck belt tension and all clamps, and pull a confirmation log before you lean on it.

Supporting Mods Every Supercharged FA24 Needs

The blower makes the power; the supporting mods keep it alive. The FA24 is known for high oil temperatures on track even when stock, and boost only adds heat. Prioritize oil cooling first, then breathing and driveline. Here are the parts we install alongside the GT2 kit, in order of importance.

A dedicated oil cooler is non-negotiable on a boosted FA24. The HKS S-Type kit is the plug-and-play match for the platform, and a dual-cooler option like the Chase Bays kit is a strong budget alternative that also fits the FA24. After cooling, feed the blower with a proper intake and let the engine exhale with a freer catback.

The Supercharger Support Package at a Glance

Here is the full build package we recommend around the HKS GT2 supercharger for a 2022-2024 GR86 or BRZ, with the job each part does and current NLP Performance pricing. The supercharger is the top pick; the rest keep it cool, fed, and flowing.

HKS GT2 Supercharger: Pros and Cons

Other Ways to Add Power to the FA24

A supercharger is the most complete path, but it is not the only one. For a lower up-front spend, a wet nitrous system adds instant power on demand: the Nitrous Express plate kit for the platform is adjustable from 35 to 100 extra horsepower via jetting, making it a popular drag-strip or roll-racing add-on. It does not raise off-boost output the way a blower does, and it requires disciplined tuning and fresh spark plugs, but it is a proven power adder. Many owners also start with breathing and sound — a Remark Elite Spec catback, for example, wakes up the FA24's exhaust note before they commit to forced induction.