Adding forced induction to a naturally aspirated engine is one of the most effective ways to unlock serious horsepower. For the Mitsubishi Eclipse—whether you're running the 420A or the legendary 4G63—a Vortech centrifugal supercharger offers a proven path to gains of 150+ horsepower without the complexity of a turbo swap. Unlike traditional roots‑type blowers, Vortech’s centrifugal design compresses air efficiently, generating consistent boost across the rpm range while maintaining excellent throttle response. This guide provides an authoritative, step‑by‑step approach to installing a Vortech supercharger on your Eclipse, covering kit selection, preparation, mechanical installation, fuel system upgrades, tuning, and long‑term maintenance.

Understanding the Vortech Supercharger System

Vortech superchargers use a high‑speed impeller to draw in ambient air, compress it, and force it into the intake manifold. The centrifugal design is compact and belt‑driven, which means it does not require an external oil feed or separate lubrication system—most Vortech kits for the Eclipse come with a self‑contained oil reservoir. This simplicity makes installation straightforward for a skilled DIY mechanic.

The key advantage of a Vortech over a turbocharger is immediate boost delivery. Because the supercharger is mechanically linked to the crankshaft, boost pressure rises almost instantly with throttle position. For daily driving and track use, this translates to predictable power delivery. Horsepower gains of 150–200 hp at the wheels are realistic with proper tuning, supported fuel system upgrades, and modest boost levels (8–12 psi).

Before diving into installation, you must choose the correct Vortech kit for your specific Eclipse model and engine. Vortech offers kits for both the 2.0L 4G63 turbo (Eclipse GSX/GST) and the 2.0L 420A (Eclipse GS/RS). While the 4G63 already has a robust bottom end, the 420A requires careful attention to fuel delivery and engine management. Check Vortech’s official website for the latest application guide and part numbers.

Selecting the Right Vortech Kit for Your Eclipse

Mitsubishi Eclipse production spanned several generations, each with distinct engine options. The most common Vortech‑friendly platforms are:

  • 2G Eclipse (1995–1999) – 420A engine: The non‑turbo four‑cylinder benefits greatly from a centrifugal supercharger. Vortech’s kit for the 420A includes a custom intake pipe, fuel pressure regulator, and a tuneable FMU (Fuel Management Unit). Expect 150–180 rwhp with the included calibration.
  • 2G Eclipse (1995–1999) – 4G63 engine: The turbocharged GSX and GST already have forged connecting rods and a capable fuel system. A Vortech supercharger can be added for linear boost, often requiring only an upgraded fuel pump and larger injectors. Power levels of 300–400 whp are achievable with proper intercooling.
  • 1G Eclipse (1990–1994): Kits exist but are rarer. The 4G63 in the 1G responds well; however, the engine management system is older. Standalone ECU or a piggyback fuel controller is recommended.

Always confirm your kit includes all necessary brackets, belts, pulleys, intake tubing, oil lines, and hardware. Many suppliers like Summit Racing stock complete Vortech systems and provide technical support for Eclipse applications.

Tools and Materials Needed

A thorough installation requires proper tools and consumables. Beyond the Vortech kit itself, gather the following:

  • Socket set (metric, 8mm–19mm) with extensions and a ratchet
  • Combination wrenches (metric sizes)
  • Torque wrench (ft‑lb and in‑lb ranges)
  • Screwdrivers (flathead and Phillips)
  • Vacuum gauge (for checking manifold pressure)
  • Fuel pressure gauge (with Schrader valve adapter)
  • Hose clamp pliers and standard pliers
  • Oil for supercharger (Vortech recommends their specific oil or an equivalent synthetic 5W‑30)
  • Antifreeze or coolant (if removing the radiator hose)
  • Thread locker (blue Loctite) for bracket bolts
  • Shop rags, safety goggles, and mechanic gloves
  • Floor jack and jack stands (if working underneath the vehicle)

Having a factory service manual (FSM) for your Eclipse is invaluable. It provides torque specifications, bolt sizes, and clearance diagrams that the Vortech instructions may not cover.

Preparation Steps

Proper preparation minimises mistakes and ensures the supercharger installation proceeds without unnecessary setbacks.

Workspace and Safety

Set up the car on level ground in a well‑ventilated area. Disconnect the battery negative terminal first to eliminate the risk of short circuits or accidental fuel pump activation. Allow the engine to cool completely if it has been running; hot components can cause burns.

Drain Coolant and Remove Obstructions

For most Vortech kits, the supercharger mounts on the passenger side of the engine bay, occupying the space previously held by the air intake. Drain the radiator enough to lower the coolant level below the thermostat housing—this makes removing hoses easier. Then remove:

  • Stock air filter and intake tube
  • Mass airflow sensor (MAF) – if retaining a MAF‑based tune, you may need to relocate it.
  • Upper radiator hose (if it interferes with bracket placement)
  • Accessory drive belt (serpentine belt) – note the routing diagram before removal.

Remove the Throttle Body and Intake Manifold

Depending on your kit, you may need to remove the throttle body and intake manifold to install the supercharger bracket base. Use a torque wrench to avoid overtightening when reinstalling. Replace intake manifold gaskets if they show signs of wear.

Step‑by‑Step Vortech Supercharger Installation

Follow these steps in order. Consult your kit’s specific instructions for torque values and belt routing, as variances exist between Eclipse models.

Mount the Supercharger Bracket

Clean all mounting surfaces on the engine block and the bracket. Apply a small amount of blue Loctite to the bolts and torque them to specification (typically 35–45 ft‑lb). The bracket must be rigid to prevent belt misalignment. Verify that the supercharger mounting pad is parallel to the crankshaft pulley.

Install the Vortech Supercharger Unit

Lift the supercharger into position on the bracket. Align the pulley grooves with the crankshaft pulley and water pump pulley. Secure with the provided bolts and torque per the instruction sheet. If the kit includes a drive belt tensioner, install it now. Rotate the engine by hand to check that the belt tracks straight and does not rub against any hoses or wiring.

Connect the Intake Piping and Intercooler

Most Vortech kits for the Eclipse come with an air‑to‑air intercooler core. Mount the intercooler (usually in front of the radiator) using the supplied brackets. Run the charge air piping from the supercharger outlet to the intercooler, then to the throttle body. Use silicone couplers and T‑bolt clamps for a leak‑free seal. Check all connections twice—even a small leak will reduce boost and power.

Install Oil Supply and Return Lines

Vortech centrifugal superchargers use an internal oil reservoir that requires a dedicated supply line from the engine’s oil pressure port. Use a T‑fitting to tap into the oil pressure sending unit. Run the supply line to the supercharger’s oil inlet; the return line routes back to the oil pan via a bung. Ensure the return line has a continuous downward slope to prevent air pockets. Fill the supercharger reservoir with the recommended oil (approximately 8 ounces).

Fuel System Upgrades

Adding boost increases fuel demand. At minimum, install an uprated fuel pump (Walbro 255 LPH or equivalent) and a fuel pressure regulator. The Vortech kit typically includes an FMU (fuel management unit) that raises fuel pressure proportionally to boost. However, for reliable tuning, consider upgrading to larger fuel injectors (440cc for the 420A, 550cc+ for the 4G63) and an aftermarket ECU such as ECMLink or a standalone unit. This allows precise fuel and ignition control.

Reassembly and Final Connections

Reinstall Throttle Body and Intake Manifold

With the supercharger and piping in place, reattach the throttle body and intake manifold. Use new gaskets and torque to specification. Attach any vacuum lines that were disconnected (brake booster, PCV, etc.). Verify the throttle cable has adequate slack and does not bind.

Belt Routing and Tension

Fit the new supercharger drive belt according to the included diagram. Most Vortech installations use a dedicated belt running from the crankshaft to the supercharger pulley, bypassing the alternator and power steering. Adjust the tensioner so the belt deflects 1/4 to 1/2 inch when pressed firmly. Too tight risks bearing damage; too loose causes slippage under boost.

Reconnect Battery and Check Fluids

Reattach the negative battery terminal. Fill the cooling system with fresh coolant and bleed air pockets by running the engine with the radiator cap off until the thermostat opens. Check oil level and top off if necessary. Start the engine briefly to circulate the supercharger oil, then recheck the reservoir level.

Testing and Tuning

Do not drive the car aggressively until the installation has been thoroughly validated.

Leak Inspection

With the engine idling, spray carburetor cleaner around all intake joints and gaskets. If the idle speed changes, you have found a vacuum leak. Also inspect oil lines and coolant hoses for drips. Tighten clamps or replace O‑rings as needed.

Fuel Pressure and Boost Verification

Attach a fuel pressure gauge to the Schrader valve on the fuel rail. At idle, pressure should be 40–45 psi (references may vary for your kit). Under load, fuel pressure should rise 1:1 with boost. Next, install a boost gauge and take a short test drive while monitoring boost. Keep engine rpm below 3000 and boost below 3 psi during the initial shakedown. If everything checks out, perform three gentle full‑throttle pulls to 5000 rpm, logging fuel pressure and boost. Aim for 6–8 psi with the stock FMU calibration.

Ignition Timing and Dyno Tuning

Centrifugal superchargers increase cylinder pressure, making detonation a real risk. Retard ignition timing by 2–4 degrees across the rpm range for the first tank of gas. Use 93 octane fuel (or higher) during the break‑in period. For maximum safe power, schedule a dyno session with a tuner experienced in forced‑induction Mitsubishi engines. A proper tune can extract 150+ reliable horsepower while keeping air/fuel ratios in the safe zone (11.5–12.0:1 under boost).

Maintenance and Longevity

Supercharger reliability depends on regular care. Change the supercharger oil every 15,000 miles or annually—Vortech sells a drain kit that makes the job simple. Inspect the drive belt monthly for glazing or cracks; a failing belt can snap and damage pulleys. Also check the intercooler fins and clean them of debris to maintain cooling efficiency. For the Eclipse, keep an eye on fuel trims; any significant deviation indicates a vacuum leak or failing fuel pump.

Common Pitfalls to Avoid

  • Ignoring fuel system limitations: The stock fuel pump and injectors cannot supply enough fuel for even 6 psi of boost. Upgrading them is mandatory.
  • Over‑tightening the belt: This places excessive load on the supercharger bearings and can cause premature failure. Use a tension gauge if available.
  • Skimping on engine management: Relying solely on the FMU leaves power on the table and raises detonation risk. Invest in a tuneable ECU.
  • Neglecting intercooler ducting: Without proper airflow to the intercooler, intake air temperatures skyrocket under boost, reducing power and potentially causing knock.
  • Forgetting to retorque bolts after 500 miles: Vibrations can loosen bracket bolts and intake clamps. Recheck all fasteners after the first few drives.

Conclusion

Installing a Vortech supercharger on your Mitsubishi Eclipse is a project that rewards careful preparation and methodical execution. With a correctly installed system, you will gain more than 150 horsepower in a linear, easy‑to‑drive fashion—transforming the Eclipse into a thrilling street machine or reliable track car. Start by selecting the proper kit for your engine generation, upgrade the fuel system without shortcuts, and invest in professional tuning. Follow this guide, consult the Vortech instruction manual, and you will enjoy many miles of boosted driving. For additional technical resources, the DSMTuners forum offers decades of Eclipse forced‑induction knowledge.