Introduction: Unleashing the NSX’s True Potential

The Acura NSX is already a legendary mid-engine sports car, celebrated for its balanced chassis, responsive VTEC V6, and daily-driver usability. Yet for many enthusiasts, the factory 270–290 horsepower leaves room for improvement—especially when modern competitors pack 400+ horsepower. A proven solution is the HKS supercharger kit, which bolts onto the C30A or C32B engine to deliver a reliable 75 horsepower gain at the wheels. This guide provides a comprehensive, step-by-step walkthrough for a DIY installation, covering everything from tool selection to post-installation tuning.

Before diving in, note that this project demands mechanical skill, attention to detail, and a full weekend of undisturbed work. If you’re not confident in your abilities, consider professional installation at a shop experienced with forced induction on the NSX. The reward, however, is a transformed driving experience: improved throttle response, a wider powerband, and that unmistakable supercharger whine.

Understanding the HKS Supercharger Kit for the NSX

HKS offers two primary supercharger setups for the NSX: the HKS GT2 Supercharger Kit (for 1991–1994 models with the 3.0L C30A) and the HKS GT2 Supercharger Kit for 1995–2005 models (3.2L C32B). Both use a centrifugal supercharger design, which compresses air efficiently without the heat soak common with roots-type blowers. The kit includes a cast aluminum intake manifold, charge cooler, blow-off valve, and all necessary brackets, belts, and hoses.

According to HKS, the kit delivers 75–90 horsepower depending on engine condition and tuning. To achieve the full 75 hp gain, you must pair the installation with a proper ECU tune—either a standalone unit like the AEM EMS or a reflash from a specialized tuner. A link to HKS official specs provides more detail on pulley ratios and boost pressure (typically 6–7 psi).

Tools and Materials Required

Having everything on hand before you start prevents frustrating trips to the auto parts store. Below is a comprehensive list.

Essential Tools

  • Complete metric socket set (1/4” and 3/8” drive) with extensions
  • Torque wrench (capable of 10–100 ft-lb)
  • Combination wrenches (8–19 mm)
  • Screwdrivers (flathead and Phillips)
  • Pliers, hose clamp pliers, and wire cutters
  • Vacuum/pressure tester (for boost leak checking)
  • Coolant funnel and drain pan
  • Oil catch pan and funnel

Kit and Consumables

  • HKS supercharger kit for your NSX year
  • New OEM coolant (Honda Type 2 or equivalent, ~2 gallons)
  • High-quality engine oil (5W-30 synthetic for C30A, 10W-30 for C32B)
  • Thread lock compound (medium strength)
  • Shop manual for Acura NSX (essential for torque specs and routing diagrams)
  • Rags, safety glasses, and nitrile gloves

If your car has high mileage, consider replacing the water pump and timing belt while you’re this deep into the engine bay—it’s excellent preventive maintenance. A resource like NSX Prime forums offers community advice on common pitfalls.

Preparation: Getting the Engine Bay Ready

Proper preparation minimizes risk of contamination and ensures the supercharger installation proceeds smoothly.

1. Disconnect the Battery

Disconnect the negative (ground) terminal first, then the positive terminal. Wait at least 15 minutes for the airbag capacitor to discharge. Place the battery in a safe location away from metal conductive surfaces.

2. Remove the Engine Cover and Airbox

With the engine cover unbolted, remove the stock intake system: unclip the MAF sensor, disconnect the resonator box, and extract the OEM air filter housing. Set aside the gaskets—they may be reused if undamaged, but new ones are cheap insurance.

3. Drain the Coolant

Place a drain pan under the radiator petcock (passenger side). Open the petcock and remove the radiator cap to speed drainage. After draining, close the petcock and move the pan under the front engine coolant bleed bolt to catch residual fluid when you disconnect hoses.

For easier access to the supercharger mounting area, unbolt both radiator fans (12 mm bolts) and gently set them aside. You don’t need to disconnect the wiring; just zip-tie the fans out of the way.

5. Inspect Belts and Pulleys

Check the serpentine belt condition. The HKS kit uses its own drive pulley, so you’ll need to remove the existing belt. Replace it if cracked or glazed.

Installing the HKS Supercharger

Follow these steps in sequence. Torque values are critical—use the shop manual for OEM bolts and HKS’s instructions for the supercharger bracket.

1. Remove the Stock Intake Manifold

Disconnect the throttle cable, vacuum lines, and fuel rail (depressurize the system first by pulling the fuel pump relay). Remove the intake manifold by loosening the six 12 mm bolts. Be careful not to bend the gasket surface. Clean the manifold mating area on the heads with a razor blade and solvent.

2. Install the HKS Bracket and Drive Pulley

The HKS bracket mounts to the front of the engine using the existing alternator and water pump bolt holes. Apply thread lock to the bolts and torque to spec (usually 35 ft-lb for M8, 55 ft-lb for M10). Next, install the supercharger drive pulley onto the crankshaft harmonic balancer using the supplied bolts.

3. Mount the Supercharger Unit

Slide the supercharger onto its bracket and align the belt pulley. The belt tensioner will be adjusted later. Bolt the supercharger to the bracket using three M10 bolts (45 ft-lb). Do not fully tighten until you verify belt alignment with a straightedge.

4. Install the Charge Cooler and Intake Piping

The HKS kit includes a charge air cooler (air-to-air or air-to-water depending on version). Mount it in the location recommended by the instructions—usually between the supercharger outlet and the throttle body. Connect the silicone hoses and secure with constant-tension clamps. Then route the intake pipe from the air filter (relocated to the driver side) to the supercharger inlet. Ensure all connections are snug but not overtightened to avoid damaging silicone.

5. Connect the Blow-off Valve and Vacuum Lines

Install the blow-off valve on the charge pipe using the included fittings. Route a vacuum line from the intake manifold to the BOV to ensure proper operation. Also connect any boost reference lines for the fuel pressure regulator if your kit includes one.

6. Install the Cooling System Components

Reconnect all coolant hoses: the HKS kit may require an additional coolant line for the charge cooler (if it’s water-cooled). Refill with fresh Honda Type 2 coolant mixed 50/50 with distilled water. Bleed the cooling system by raising the front of the car, opening the bleed valve on the thermostat housing, and filling until no air bubbles emerge.

7. Reassemble the Engine Bay

Reinstall the radiator fans, airbox (now repositioned), and engine cover. Double-check that all electrical connectors are fastened and that no tools are left in the engine compartment.

Post-Installation Steps and Tuning

Mechanical installation is only half the battle. Without proper tuning, the car will run excessively lean or rich, risking detonation or poor drivability.

1. Reconnect the Battery and Prime the Oil System

Reconnect the battery, negative first. Before cranking the engine, spin the supercharger belt by hand to ensure it rotates smoothly. Then, disable the ignition and crank the engine for 10 seconds to build oil pressure.

2. Start and Idle Check

Start the engine and let it idle. Listen for unusual noises: belt squeal, boost leaks, or metallic sounds. Check the fuel pressure (should be 38–45 psi at idle). If the engine runs rough, verify vacuum line routing and MAF sensor wiring.

3. ECU Tuning

You must upload a base map designed for the HKS supercharger. This can be done via a standalone ECU (e.g., AEM Infinity, Hondata K-Pro with an adapter) or a reflash of the stock ECU by a specialist. A reputable tuner for NSX forced induction is Science of Speed, which offers pre-calibrated ECU files. Without tuning, the 75 hp gain will not materialize—and you risk engine damage.

4. Boost Leak Test

Pressurize the intake system to 10 psi using a boost leak tester. Soapy water on all connections will reveal bubbles. Any leak must be fixed before road testing.

Performance Expectations and Driving Impressions

After a proper tune, you can expect 330–350 wheel horsepower from a 3.0L NSX, up from the stock 255–270 whp. Torque jumps from ~190 lb-ft to 250 lb-ft, with a flat curve from 4000–7000 rpm. The supercharger spools quickly, providing linear power that feels like a larger-displacement engine. The iconic VTEC crossover becomes even more aggressive as boost builds.

Fuel economy will drop by 2–4 mpg during spirited driving, but highway cruising remains near stock. The HKS unit is remarkably quiet at cruise, with an audible whine under full throttle—an addicting soundtrack.

Maintenance and Long-Term Reliability

A properly installed HKS supercharger can last 50,000+ miles with routine care. Key maintenance intervals:

  • Change supercharger oil every 15,000 miles (use HKS-approved fluid)
  • Inspect belt tension monthly for the first 1,000 miles, then every oil change
  • Check charge cooler hoses for cracking every 2 years
  • Keep the air filter clean—oiled cotton filters require re-oiling every 10,000 miles

If you track the car, consider upgrading the radiator to a dual-core unit and adding an oil cooler to manage increased heat loads.

Conclusion

Installing an HKS supercharger on your Acura NSX is one of the most rewarding modifications you can make. The 75 horsepower gain transforms the car from a quick vintage exotic to a modern performance contender, all while preserving Honda’s legendary reliability. By following this guide meticulously—especially the preparation and tuning steps—you’ll enjoy a trouble-free setup that makes every drive an event. For additional resources, the HKS USA website provides kit-specific PDFs, and the NSX community on NSX Prime offers troubleshooting threads from hundreds of successful installs.