Installing the HKS GT Supercharger Kit on your Infiniti Q50 VR30DDTT can be one of the most transformative modifications you can make, delivering a verified boost of over 150 wheel horsepower. This comprehensive DIY guide covers the entire process—from gathering the correct tools and preparing the vehicle to final tuning considerations. The VR30DDTT engine is already a stout performer, but adding forced induction via a supercharger provides immediate, linear power without the lag associated with larger turbochargers. By following this guide, you will be able to complete the installation in a well-equipped home garage, assuming you have intermediate mechanical experience and a solid understanding of engine systems.

Understanding the HKS GT Supercharger Kit

The HKS GT Supercharger Kit is designed specifically for the Nissan VR30DDTT engine found in the Q50 and Q60. It uses a twin-screw supercharger that compresses air efficiently and reliably. The kit includes all necessary components: the supercharger unit, intake piping, intercooler, blow-off valve, fuel injectors, and a belt drive system. HKS also provides a dedicated ECU tune via a flash or piggyback system to handle the increased air volume and fuel demands. The result is a substantial horsepower gain while retaining drivability and emissions compliance (where applicable).

Before purchasing, verify that your Q50 is equipped with the VR30DDTT—some earlier models or base trims may have a different powerplant. The kit is compatible with both automatic and manual transmissions, though automatic models often require additional transmission cooling if you plan to track the vehicle. For more technical specifications, consult the official HKS product page: HKS Supercharger Information.

Pre-Installation Planning

Proper planning prevents poor performance. Take time to review all instructions that come with the HKS kit. Some aftermarket revisions exist, so ensuring you have the latest version is critical. Also confirm that your vehicle’s engine, cooling, and fuel systems are in good condition. Compression and leak‑down tests are recommended before starting the install. Any existing issues will only be amplified by increased power.

You will need to drain engine oil and coolant, so have fresh fluids ready. The supercharger itself requires gear oil (usually 75W-90), so purchase a bottle of high-quality synthetic gear oil as well. Consider upgrading the fuel pump if your Q50 is a 2016–2018 model year; early VR30DDTT fuel pumps may not support the additional fuel flow required for 150+ hp gains. Many tuners recommend a fuel pump upgrade as a supporting mod. Check community forums like Q50Forum for model-specific experiences.

Required Tools and Materials

Below is a comprehensive list of tools and materials. Not every item is strictly necessary, but having them on hand will prevent mid-project trips to the auto parts store.

  • HKS GT Supercharger Kit (complete with brackets, belt, intercooler, piping, injectors, and ECU module)
  • Metric socket set (8mm to 19mm), including deep sockets and extensions
  • Wrenches (combination and ratcheting)
  • Torque wrench (capable of 10–100 lb-ft)
  • Pry bar and rubber mallet
  • Pick set for removing hoses and electrical connectors
  • Jack and jack stands (at least 2 stands, but 4 are better for stability)
  • Coolant catch pan and oil drain pan
  • New engine oil and filter (5W-30 recommended)
  • Distilled water and coolant concentrate for refill
  • Supercharger gear oil (75W-90, approx. 1 liter)
  • Shop rags, brake cleaner, and thread locker (medium strength)
  • Safety glasses, mechanic gloves, and a fire extinguisher (important: fuel lines will be disconnected)
  • Factory service manual or wiring diagram for the Q50 VR30DDTT

Safety Precautions

Working on a forced induction system involves high-pressure fuel, hot coolant, and heavy components. Always work in a well-ventilated area. Disconnect the battery negative terminal before starting any electrical work. When jacking the car, use proper jack stands and never rely on a hydraulic jack alone. The front of the Q50 must be elevated to access the lower intercooler and piping; ensure the vehicle is level on all four stands for safety. Wear safety glasses when disconnecting pressurized coolant hoses. Have absorbent material on hand for any fuel or oil spills.

Step-by-Step Installation

The installation process can be broken down into major phases. Each phase must be completed carefully to avoid damage to the supercharger or engine.

1. Vehicle Preparation and Fluid Drain

  • Disconnect the battery (negative terminal).
  • Raise the front of the vehicle and secure it on jack stands. Remove the under-engine splash shield.
  • Drain engine oil into a suitable container. Remove the oil filter and discard it.
  • Drain coolant from the radiator drain petcock and engine block drain bolt (if accessible).

2. Removing Stock Intake Components

  • Remove the factory air filter boxes and intake pipes. Unplug the MAF sensors carefully.
  • Disconnect the charge air cooler (CAC) piping that routes from the turbochargers to the intercooler. You will be replacing much of this with HKS piping.
  • Unbolt the stock intercooler and remove it. Note the mounting points—the HKS intercooler uses the same locations.
  • Disconnect the electronic throttle body connectors and unbolt the throttle bodies from the intake manifold. Set aside.

3. Removing the Intake Manifold and Accessories

  • Label and disconnect fuel lines from the direct injectors (high pressure). Use caution—fuel pressure may still be present. Depressurize the system by removing the fuel pump fuse and cranking the engine briefly before disconnection.
  • Unplug all electrical connectors to the intake manifold, including EVAP and manifold absolute pressure (MAP) sensors.
  • Remove the intake manifold bolts in a crisscross pattern. Lift the manifold off carefully—it may be stuck due to gasket adhesion.
  • Remove the engine cover and belt drive components that will interfere with the supercharger bracket. This usually includes the serpentine belt and the idler pulley.

4. Supercharger Bracket and Mounting

The HKS GT kit uses a custom bracket to mount the supercharger in place of the stock intake manifold. Clean the mounting surface thoroughly. Apply a thin layer of thread locker to the bracket bolts and torque them to the specifications provided in the HKS manual (typically 35–45 lb-ft).

  • Install the supercharger onto the bracket. Use the supplied gasket or O-ring between the supercharger and the adapter plate.
  • Tighten mounting bolts evenly to avoid warping the supercharger housing.
  • Mount the supercharger belt tensioner and install the drive belt. Adjust tension according to kit instructions—too loose will slip, too tight can damage bearings.

5. Connecting Fuel and Electrical Systems

  • Install the larger fuel injectors provided in the HKS kit. Apply a small amount of assembly lubricant to the O-rings to prevent damage.
  • Reconnect the fuel lines. Use new crush washers if your vehicle uses banjo fittings.
  • Plug in the throttle bodies and all intake manifold sensors. The HKS kit includes a custom wiring harness for the supercharger bypass valve and the MAP sensor relocation. Follow the supplied wiring diagram carefully.
  • Install the HKS ECU tune module. This is typically a piggyback unit that splices into the factory ECU harness. Secure it away from heat sources and moisture.

6. Intercooler and Cooling System Connections

  • Mount the HKS intercooler (air-to-water or air-to-air, depending on kit revision). Use all provided brackets.
  • Connect the intercooler piping. Ensure all silicone hoses are seated fully and clamps are tightened evenly.
  • For the supercharger’s own cooling circuit, attach the coolant lines from the supercharger to the auxiliary water pump and heat exchanger. Bleed the system of air by operating the pump with the cap off.
  • Refill the engine coolant with a 50/50 mix of distilled water and ethylene glycol. Use a funnel with a long neck to avoid spills.

7. Final Assembly and Belt Check

  • Reinstall the under-engine splash shield and lower the vehicle.
  • Fill the engine with fresh oil (5W-30) and install a new oil filter.
  • Fill the supercharger gear case with the specified gear oil. Check the level using the hex plug—oil should just start to drip out when level.
  • Double-check all electrical connections. Reconnect the battery.

Tuning and ECU Considerations

The HKS kit typically includes a flash tune or a piggyback controller. If your vehicle is a later model (2019+) with locked ECUs, you may need a standalone unit or a remote tune from a trusted calibrator. Do not attempt to drive the car without proper calibration—the stock fuel and timing maps will cause detonation and engine damage. A proper tune should be done on a dyno or via an ecutek remote tune. For more information on custom tuning, visit ECUTEK to find a certified tuner near you.

After the initial startup, allow the engine to reach operating temperature while monitoring coolant temp, oil pressure, and supercharger oil level. Look for any unusual whining or knocking. The HKS supercharger has a characteristic whine that is normal, but anything metallic or grinding requires immediate investigation.

Post-Installation Checks and Break-In

Before hammering the throttle, perform a careful break-in procedure. Drive gently for the first 100–200 miles under varying loads and RPMs, avoiding sustained high boost. This allows the supercharger gears to bed in and the ECU to adapt. Check all fasteners after the first heat cycle—many will loosen slightly as components settle. Retorque the supercharger mounting bolts and intercooler clamps.

Inspect for fluid leaks daily for the first week. Pay close attention to coolant connections and the supercharger oil fill plug. If you detect air in the cooling system, bleed it again using the procedure in the HKS manual.

Performance Expectations

With the HKS GT Supercharger Kit properly installed and tuned, your Q50 VR30DDTT will produce an estimated 480–520 wheel horsepower on a dyno, depending on fuel quality and supporting mods. That translates to a 150+ hp gain over stock. Acceleration from 0–60 mph will drop into the mid-3-second range with sticky tires. The supercharger provides a linear powerband that pulls hard all the way to redline, making everyday driving more responsive and exhilarating. For comparison, many owners report consistent quarter-mile times in the low 11-second range. Always use high-octane pump fuel (93/91 RON) or ethanol blends if tuned accordingly.

Maintenance Tips

  • Change supercharger gear oil every 30,000 miles or as recommended by HKS.
  • Inspect the drive belt for glazing or cracks every 15,000 miles.
  • Clean the air filter element at each oil change—it's a high-flow unit that can clog in dusty conditions.
  • Monitor boost pressure via a gauge or OBD2 scanner; creeping boost could indicate a wastegate issue.
  • Use a catch can to reduce oil blow-by into the supercharger intake—this is especially important for direct injection engines.

Conclusion

Installing the HKS GT Supercharger Kit on your Q50 VR30DDTT is a demanding but highly rewarding project. The horsepower gains are genuinely transformative, turning the Q50 into a serious performance machine. With the correct tools, patience, and attention to detail, any competent DIY enthusiast can complete this installation in a weekend. Always prioritize safety, double-check your work, and never compromise on tune quality. For ongoing support, join the VR30DDTT community forum where experienced owners share tips and troubleshooting advice. Once everything is buttoned up, you will experience one of the most exciting upgrades available for the platform.