Installing a Stillen supercharger on your Nissan 350Z is one of the most effective ways to transform the car's naturally aspirated VQ35DE or VQ35HR engine into a forced-induction powerhouse. The Stillen supercharger kit is engineered specifically for the 350Z platform, providing a significant horsepower increase—typically from the stock 287–306 hp to over 400 hp at the wheels—while maintaining drivability and reliability. This guide walks you through the entire installation process, from preparation to test driving, with the depth needed for an advanced DIY mechanic or an experienced tuner. We'll cover tools, removal, installation of the supercharger unit, hose routing, ECU considerations, and post-installation checks. Always refer to the official Stillen installation manual for your specific kit (available at Stillen's website) and consider consulting a professional if you're not comfortable with engine bay modifications.

Tools and Materials Needed

Before you begin, gather all the necessary tools and consumables. Having everything on hand prevents interruptions and ensures the job proceeds smoothly. The Stillen supercharger kit (typically the Stillen Stage 1 Supercharger Kit for the 350Z) includes the supercharger unit, mounting brackets, pulleys, belt, intake piping, intercooler (if applicable), fuel injectors, and a reflash or piggyback ECU. In addition, you'll need the following:

  • Socket set (metric, 8 mm to 19 mm) with extensions and a universal joint
  • Torque wrench (ft-lb and in-lb ranges)
  • Combination wrenches (10 mm, 12 mm, 14 mm, 17 mm)
  • Screwdrivers (Phillips and flathead)
  • Vacuum hose (if not included in the kit, silicone hose of appropriate size)
  • Coolant (Nissan long-life coolant or equivalent, pre-mixed)
  • Engine oil (5W-30 or as recommended for your climate; you'll drain and refill)
  • Safety glasses and mechanics gloves
  • Jack and jack stands or a lift
  • Drain pan for coolant and oil
  • Shop towels and brake cleaner for cleaning surfaces
  • Multimeter (if needed for electrical checks)
  • OBD-II scanner (for clearing codes and verifying sensor readings)

Ensure your Stillen kit is complete and matches your 350Z's model year—pre-2006 VQ35DE and 2006+ VQ35HR have different intake ports and fueling requirements. Double-check the pulley size (often 3.12″ or 3.33″) to match your desired boost level.

Preparation Steps

Proper preparation reduces the chance of mistakes and damage. Follow these steps before touching any engine components:

  • Park the 350Z on a level, clean surface. Engage the parking brake and chock the rear wheels.
  • Disconnect the battery: Remove the negative terminal first, then the positive. This prevents accidental shorts and resets the ECU.
  • Allow the engine to cool completely if it has been running. Coolant and oil should be at ambient temperature.
  • Read the entire Stillen installation manual that came with your kit. Pay attention to torque specs and specific steps for your model year.
  • Take photos of your stock engine bay from multiple angles. This helps when rerouting hoses and reassembling.
  • Drain the coolant from the radiator (using the petcock at the bottom) and drain the engine oil. Replace the oil drain plug and oil filter with new ones (you'll refill later).
  • Remove the engine undercover if you have one, for better access.

If you plan to install a boost controller or additional gauges (boost, oil temp, AFR), now is the time to run wiring and install senders. Many enthusiasts also upgrade the fuel pump (Walbro 255 lph or AEM 340) to support higher fuel flow—consult your tuning requirements.

Removing the Stock Components

Clear the engine bay of parts that will interfere with the supercharger mounting. Work methodically and keep fasteners organized in labeled bags.

  1. Remove the engine cover: Unbolt the plastic cover (four bolts, 10 mm). Set it aside.
  2. Disconnect the intake system: Unclip the mass airflow sensor (MAF) connector. Loosen the hose clamps on the intake tube and remove the entire factory intake assembly—airbox, filter, and piping. Keep the MAF sensor safe; you will reinstall it on the new Stillen intake.
  3. Remove the throttle body: Disconnect the electrical connector and coolant lines (if your model has them). Unbolt the throttle body (four bolts, 10 mm) and carefully set it aside. The gasket can be reused if undamaged.
  4. Remove the intake manifold: On the VQ35DE, the intake manifold is plastic. Unbolt it (10 mm and 12 mm bolts) and disconnect the vacuum lines and PCV hoses. You may need to remove the fuel rail covers and injector harnesses. For VQ35HR, the manifold is aluminum and similar procedure. Keep the manifold gasket; you may need a new one if damaged.
  5. Remove the serpentine belt: Use a 14 mm wrench to tension the belt tensioner and slip the belt off the pulleys.
  6. Remove the factory alternator bracket (if applicable): Some Stillen kits relocate the alternator. Unbolt the alternator (three bolts, 12 mm) and set it aside without disconnecting the wiring yet.
  7. Remove the power steering pump bracket (if applicable): The supercharger mounting might require removing or relocating the pump. Follow the kit instructions.

Take care not to drop any bolts or debris into the engine's open intake ports. Cover the ports with clean towels or tape while working.

Installing the Stillen Supercharger

With the engine bay stripped down, you can now mount the supercharger unit. This is the core of the installation—take your time and follow torque specs precisely.

  • Install the Stillen mounting bracket: Bolt the supplied bracket to the engine block using the OEM mounting points for the alternator/power steering. Apply thread locker (Loctite blue) to bolts as instructed. Torque to spec (usually 35–45 ft-lb for M10 bolts).
  • Attach the supercharger: The Stillen unit (based on an Eaton TVS or Vortech-style, depending on version) comes pre-assembled. Position it onto the bracket and align the pulley with the crank pulley. Use the supplied bolts and washers; torque to spec (often 35–40 ft-lb). Do not overtighten as the supercharger casing is aluminum.
  • Install the supercharger belt: Route the new longer belt around the crank pulley, supercharger pulley, tensioner, and idler pulleys as diagrammed. Use a belt tool or large wrench to retract the tensioner while slipping the belt over the final pulley. Ensure the belt is seated fully in all grooves.
  • Reinstall the alternator and power steering pump: If they were relocated, use the Stillen-provided brackets. Tighten bolts to spec and reattach electrical connectors.
  • Mount the intercooler (if included): For Stage 2 kits, there is an air-to-water intercooler. Install the core in front of the radiator (or in the intake path) and run the water pump and hoses. For Stage 1, the supercharger is air-to-air with a charge pipe.
  • Install the throttle body adapter and intake piping: The Stillen kit includes a spacer/adapter for the throttle body. Reinstall the throttle body onto the adapter with a new gasket supplied. Connect the large silicone couplers and aluminum pipes from the supercharger outlet to the throttle body. Use T-bolt clamps and ensure no boost leaks.
  • Install the new intake: Attach the MAF sensor to the new Stillen intake tube and mount the air filter in a cool location (usually behind the front bumper or in the fender well). Secure with the provided bracket.

Check all rotating components for clearance—spin the supercharger pulley by hand and ensure no contact with the frame or lines. Re-tension the belt after the first heat cycle.

Connecting the Necessary Hoses

Proper hose routing is critical for supercharger lubrication, cooling, and vacuum signals. Stillen kits typically include silicone hoses and a vacuum manifold.

  • Supercharger oil lines: If your kit has a remote oil feed (for centrifugal units), run a braided line from an oil pressure port (often the factory oil pressure sender location) to the supercharger, and a return line to the oil pan. Use AN fittings and ensure no kinks.
  • Coolant lines: The supercharger unit (if Eaton TVS) has coolant passages for thermal management. Connect the supplied hoses to the engine's cooling system—usually Tee into the heater core return line. Bleed the cooling system after filling.
  • Vacuum lines: Connect the bypass valve (if equipped) to manifold vacuum via the kit's vacuum manifold. Also connect the boost reference line to the fuel pressure regulator (if required) and the BOV/recirculation valve. Use zip-ties to secure hoses away from heat and moving parts.
  • Boost control solenoid (if included): For adjustable boost, install the solenoid in a dry area and run vacuum lines per the instructions.

Double-check every hose for pinches or abrasion points. Use heat-shield sleeves near exhaust manifolds. After all connections, reinstall the engine cover (if it still fits) or leave it off for better airflow.

ECU Tuning and Fuel System

Adding forced induction changes air density dramatically—your 350Z's factory ECU cannot compensate properly without reprogramming. The Stillen kit typically includes either a reflashed ECU or an ECUTek piggyback tune. If you purchased a tune from a vendor like Z1 Motorsports or Stillen directly, follow their instructions. If not, you must get a custom tune from a reputable Nissan tuner (e.g., Specialty Z, Tuning Technologies).

  • Install the provided fuel injectors: The Stillen kit comes with upgraded injectors (typically 440–600 cc depending on boost level). Remove the fuel rails and replace the injectors with new O-rings. Torque fuel rail bolts to spec (around 8 ft-lb).
  • Reflash or install the piggyback: For pre-2006 models, you may need to send your ECU to Stillen for reflashing, or use a plug-and-play module. For HR models, often an ECUTek license and flash from a local tuner is required.
  • Verify fuel pressure: Start the engine (after testing) and check fuel pressure at idle. It should be close to stock (around 50 psi). If using a rising-rate regulator, adjust to spec.

Never drive the car with a supercharger but without the correct tune—lean air/fuel ratios can damage the engine immediately.

Finalizing the Installation

After all mechanical and electrical components are in place, perform the final checks and refill fluids:

  • Reinstall any remaining factory covers (engine cover if it fits, plastic shrouds).
  • Reconnect the battery (positive first, then negative).
  • Fill the coolant system with a 50/50 mix of distilled water and Nissan LL coolant. Use a funnel and bleed the system by running the engine with the radiator cap off until the thermostat opens and bubbles clear.
  • Refill the engine oil with fresh 5W-30 (or your preferred synthetic) to the correct level. Do not overfill.
  • Inspect all clamps, bolts, and wires. Look for any loose items that could rattle or cause a short.
  • Clear the ECU memory by disconnecting the battery for a few minutes (if you haven't already) or using an OBD-II scanner.

Testing the Installation

Before taking your 350Z out on the street, perform a controlled test to confirm the supercharger is working safely:

  1. Idle test: Start the engine and let it idle for 5–10 minutes. Monitor the coolant temperature and oil pressure. Listen for any belt chirping, whining (the supercharger will have a faint whine, but no scraping). Check for leaks at all hose connections.
  2. Rev test: With the car in park/neutral, slowly rev the engine to 3,000 rpm and hold for a few seconds. Watch for the boost gauge (if installed) to show positive pressure. The BOV should not leak.
  3. Short drive: Take the car on a low-speed residential street. Keep engine speed below 4,000 rpm and avoid full throttle. Listen for pinging (detonation) or unusual noises. Check that the car doesn't stall when coasting.
  4. Boost load test: Find a safe, empty road. Gradually increase throttle to 10 psi (or your kit's recommended boost) while logging data via an OBD scanner if possible. Verify air/fuel ratio is between 11.5 and 12.0 at full boost. If you see lean conditions (AFR above 13), lift off immediately and seek a tune adjustment.
  5. Check for codes: After a 15-minute drive, scan for error codes. Common codes are P0171/P0174 (lean) if fuel maps are off, or MAF codes if the sensor is dirty or misplaced.

If everything checks out, congratulations—your 350Z is now supercharged! Allow the car to cool, then re-torque the supercharger mounting bolts and belt tension after the first heat cycle.

Maintenance and Long-Term Tips

A supercharged engine requires more attentive care. Follow these guidelines to keep your Stillen system reliable:

  • Change engine oil every 3,000–5,000 miles with high-quality synthetic. Forced induction generates more heat and contaminates oil faster.
  • Inspect the serpentine belt monthly for cracks or glazing. Replace every 20,000 miles.
  • Clean or replace the supercharger's air filter every 10,000 miles (more often in dusty conditions).
  • Check coolant level and quality annually. Supercharger cooling passages can corrode if neglected.
  • Listen for changes in supercharger whine—any increase in noise or harshness may indicate bearing wear. Rebuild kits are available from Forced Induction Rebuilders.
  • Consider a standalone engine management system (like Haltech or ECUTek) for better tuning flexibility as you add supporting mods (exhaust, larger injectors, etc.).

Conclusion

Installing a Stillen supercharger on your Nissan 350Z is a rewarding project that dramatically increases horsepower and driving excitement. By following this comprehensive step-by-step guide—ensuring proper removal, mounting, hose routing, tuning, and testing—you can achieve a reliable and powerful forced-induction setup. Remember that professional tuning is essential; even with a kit, individual engine conditions vary. Take your time, double-check every connection, and enjoy the newfound surge of power. For additional resources and community support, visit the My350Z forums where many owners have documented their own Stillen supercharger builds.