What Is the HKS Super Power Pack and Why Does It Matter for Your Eclipse?

The Mitsubishi Eclipse, particularly the turbocharged GSX and GST trims from the 2G and 3G eras, has long been a favorite among tuners for its robust 4G63 engine and relatively lightweight chassis. However, like any factory car, it leaves performance on the table. The HKS Super Power Pack is one of the most respected bolt-on upgrade kits in the JDM tuning world, designed to unlock that hidden potential without requiring a full engine rebuild. This kit bundles several key components that work together to improve airflow, fuel mapping, and ignition timing, resulting in noticeable gains in horsepower, torque, and throttle response.

Unlike piecing together parts from different manufacturers, the Super Power Pack is engineered as a system. Each component is matched to the others, which means you avoid the common tuning pitfalls of mismatched intakes, exhausts, and ECU maps. For an Eclipse owner looking for a reliable, street-friendly power increase, this kit is a proven shortcut to a more exhilarating driving experience.

Direct vs. General Applications: Matching the Kit to Your Eclipse Model

HKS has released multiple versions of the Super Power Pack over the years. Some are model-specific (e.g., for the 2G Eclipse GSX with the 4G63T engine), while others are more universal kits requiring minor modifications. Before buying, you must confirm compatibility with your Eclipse’s engine code, model year, and drivetrain. The kit discussed in this article is the most common variant intended for 1995-1999 Mitsubishi Eclipse GSX/GST (4G63T). Owners of the 3G (2000-2005) Eclipse with the 4G64 or 6G72 engines should verify that the included exhaust and intake fit their chassis.

Breaking Down the Components: What’s Inside the Box

The HKS Super Power Pack typically arrives as a large box containing several distinct subsystems. Understanding each part helps you appreciate how they contribute to the overall performance gain and why the cost is justified.

High-Performance Air Intake System

The factory airbox on the Eclipse is restrictive, designed for noise suppression and long service intervals rather than high-volume airflow. The HKS intake replaces it with a large-diameter aluminum tube and a high-flow foam or cotton filter. The filter is often an HKS Super Power Flow unit, known for its excellent filtration and reusability. The tube is mandrel-bent to reduce turbulence, and the intake is positioned to draw cooler, denser air from outside the engine bay.

This upgrade alone can add 5-8 horsepower on a stock 2G Eclipse, but its real value is in supporting the exhaust and ECU tune that come with the rest of the kit.

Upgraded Exhaust System

The kit includes a cat-back or turbo-back exhaust system, depending on the version. For most Eclipse applications, it is a cat-back system that includes a large-diameter (2.5″ to 3″) mandrel-bent pipe, a high-flow catalytic converter (or test pipe option), and a muffler with the distinctive HKS straight-through design. The result is a deep, aggressive exhaust note that is not overpowering at highway speeds but announces your arrival under full throttle.

Reducing exhaust backpressure allows the turbo to spool faster and maintain boost pressure more effectively, translating to earlier torque delivery and higher peak power.

ECU Tuning Tool and Performance Calibration

The heart of the kit is the HKS F-CON or F-CON SZ piggyback ECU (depending on the generation) with a pre-loaded performance map. This device intercepts sensor signals (MAF, MAP, O2, etc.) and modifies the fuel and ignition maps to match the increased airflow and reduced exhaust restriction. Some newer versions of the kit include a flash tool that can directly reflash the factory ECU on certain Eclipse models.

This is the component that ensures the intake and exhaust upgrades actually add power rather than just making noise. Without proper tuning, adding a free-flow intake and exhaust can cause the engine to run lean, risking detonation. The HKS ECU map is conservative enough to be safe on 91-93 octane pump gas while still unlocking significant gains.

Performance Spark Plugs

The kit often includes a set of HKS M35I or Iridium spark plugs, gapped and heat-rated for the increased cylinder pressures and temperatures from the tune. Upgraded spark plugs ensure complete combustion at higher RPM and under boost, reducing the risk of misfire.

Installation Hardware and Instructions

All necessary gaskets, clamps, brackets, bolts, and wiring harnesses are included. The instructions are typically clear with torque specs and routing diagrams, though they assume a moderate level of mechanical skill.

Detailed Cost Breakdown: What You Can Expect to Pay

The total investment for the HKS Super Power Pack installation depends on your mechanical proficiency, local labor rates, and whether you need any extra parts (e.g., replacement gaskets, new O2 sensors, or boost controller). Here is an itemized estimate based on current market prices (USD) as of 2025.

Item Cost Range
HKS Super Power Pack Kit (new, model-specific) $1,200 – $1,800
Labor – Professional installation (4-6 hours at $75-100/hr) $300 – $600
Additional parts (exhaust gaskets, extra O2 sensor bungs, fluids) $100 – $300
Optional: Dyno tuning session after installation $400 – $700
Optional: Boost controller (if not satisfied with factory boost curve) $150 – $400
Total (DIY installation, no dyno) $1,300 – $2,100
Total (professional installation + dyno) $2,000 – $3,100

Prices vary by vendor. Check authorized HKS dealers and reputable performance shops like Timing Racing or ExtremePSI for current listings. Buying a used kit can save 30-50% but inspect the ECU harness and exhaust for rust carefully.

Performance Benefits: Real-World Gains on the Eclipse 4G63T

The HKS Super Power Pack is not a magic bullet, but on a bone-stock 2G Eclipse GSX (210 hp and 214 lb-ft at the crank factory), the kit consistently delivers the following improvements as verified by owners on dyno logs posted on DSMTuners and similar forums:

  • Horsepower increase: 25–40 whp (wheel horsepower) depending on condition of the engine and fuel quality. That translates to roughly 300-320 crankshaft horsepower.
  • Torque increase: 30–50 lb-ft at the wheels, with the peak arriving 500-800 RPM earlier than stock.
  • Throttle response feels sharper because the intake and exhaust reduce restriction, and the ECU tune advances timing appropriately.
  • Boost threshold drops by approximately 200-400 RPM, meaning full spool comes sooner, making the car feel faster even in normal driving.
  • Engine efficiency: The optimized air/fuel ratio can yield a modest improvement in highway fuel economy (1-2 mpg) under steady cruise, though under heavy throttle you will use more fuel.
  • Sound quality: The HKS exhaust is well-known for its clean, deep tone without excessive drone. It adds a sporty character without being obnoxious to neighbors.

What About the 420A Non-Turbo Eclipse?

If you own a non-turbo Eclipse (420A engine), a Super Power Pack may still be available, but gains will be smaller—typically 10-15 horsepower—because there is no turbocharger to unlock with reduced backpressure. The intake and exhaust will still improve throttle response and sound, but the cost-per-horsepower ratio is less favorable. Many budget-minded owners of the 420A choose individual parts rather than the full kit.

Installation Process: Step-by-Step Guide (With Pro Tips)

Installing the HKS Super Power Pack is an intermediate-level job. Plan for a full Saturday if you are doing it yourself. Below is a general outline; always follow the included instruction manual for torque specs and routing specific to your Eclipse model.

Tools You Will Need

  • Socket set (metric, 8–19mm)
  • Torque wrench (20-100 ft-lb range)
  • Screwdrivers (flathead and Phillips)
  • Jack and jack stands (or ramps)
  • Penetrating oil (for rusted exhaust bolts)
  • O2 sensor socket (22mm)
  • Electrical tape and zip ties (for ECU wiring)

Step 1: Disconnect Battery and Prepare Engine Bay

Disconnect the negative battery terminal. Remove any engine covers or plastic shrouds that block access to the airbox and intake piping. On 2G Eclipses, the stock airbox is located on the driver’s side near the headlight.

Step 2: Remove Factory Intake System

Unplug the MAF sensor connector. Loosen the clamps on the intake tube and remove the airbox assembly. You will also need to unbolt the resonator box (if equipped). Clean the throttle body opening with a shop rag.

Step 3: Install HKS Intake

Attach the HKS intake tube to the throttle body using the supplied silicone coupler and clamps. Mount the filter in the position recommended by the instructions—usually using a bracket that bolts to existing holes. Reinstall the MAF sensor into the intake tube, making sure the arrow on the sensor points toward the engine. Torque the clamps gently to avoid crushing the plastic or metal tube.

Step 4: Remove Stock Exhaust System

This is the most labor-intensive part. Safely raise the car and support it on jack stands. Spray penetrating oil on all exhaust flange bolts and O2 sensor threads. Remove the exhaust system from the downpipe back. You may need to disconnect the O2 sensors carefully to avoid damaging the wires. On some Eclipse models, the downpipe bolts are notoriously rusty; a breaker bar and patience are essential. If bolts snap, you may need to drill out the studs—plan for extra time.

Step 5: Install HKS Exhaust

Working from the downpipe rearward, loosely assemble the exhaust sections with the new gaskets. Use anti-seize on all bolts. Once everything is aligned and hangers are in place, tighten all flanges to the torque specified in the manual (typically 30-40 ft-lb). Reinstall O2 sensors into their new bungs, using anti-seize on the threads.

Step 6: ECU Tuning Installation

If your kit includes a piggyback F-CON, locate the ECU behind the driver’s side kick panel (or passenger side, depending on model). Solder or connect the provided harness carefully, following the wiring diagram. The pre-loaded map is already installed, but you must ensure that jumper settings match your fuel injector size and turbo configuration (stock injectors and turbo are assumed). If the kit uses a flash tool, connect it to the OBD-II port and follow software instructions to upload the new tune.

Step 7: Replace Spark Plugs

Remove the spark plug wires or coils (on 4G63, remove the fuel rail and plug cover), then remove the old plugs. Gap the new HKS plugs to the spec indicated in the manual (typically 0.028″–0.032″). Install with a torque wrench to 18-20 ft-lb (do not overtighten). Reinstall the ignition components.

Step 8: Reconnect Battery and Test

Double-check all electrical connections, hose clamps, and exhaust bolts. Reconnect the battery. Start the engine and check for any exhaust leaks or vacuum leaks at the intake. Allow the engine to reach operating temperature. The vehicle may run a bit rough for the first few minutes as the ECU adapts. Take a short test drive, avoiding full throttle until you’ve verified that all parameters are normal (no check engine light, proper idle, no unusual noises).

Key Considerations Before You Buy and Install

Vehicle Compatibility and Engine Versions

As mentioned, confirm your Eclipse’s engine code (4G63T, 420A, 4G64, etc.) and model year. The HKS Super Power Pack for a 1G DSM (1990-1994) Eclipse will not fit a 2G without significant modification. Check the part number against HKS USA’s catalog. If you have a 4G63T, also verify whether your car has a MAF sensor (2G) or a MAP-based speed density system (later models).

The high-flow catalytic converter included in the kit may not be CARB (California Air Resources Board) approved. If you live in a state with strict emissions testing (California, New York, etc.), you may need to retain the factory cat or purchase an additional CARB-compliant unit. Some versions of the Super Power Pack come with a “test pipe” (no cat) intended for off-road use only. Check your local regulations. California ARB has a list of approved aftermarket parts.

Warranty Implications

Installing any performance modification can void your vehicle’s factory warranty if a failure is traced to the aftermarket part. Since most Eclipses are now well out of warranty, this is less of a concern. However, if you have an aftermarket extended warranty, read the fine print—many exclude modifications unless explicitly covered. Keep all receipts and documentation; some insurers may accept a professional installation.

Is a Professional Dyno Tune Necessary?

The pre-loaded HKS tune is safe for most stock or lightly modified 4G63Ts running 91-93 octane. However, if you have other modifications (larger injectors, bigger turbo, aftermarket cams, or a different fuel pump), the base map will be insufficient. In that case, a professional dyno tune using the HKS F-CON is strongly recommended. A good tuner can extract an additional 10-15 horsepower and ensure safe air/fuel ratios across the rev range.

Supporting Upgrades to Consider

The Super Power Pack works best when the rest of the engine is healthy. Before installation, it is wise to address common weak points on the Eclipse 4G63T:

  • Upgraded fuel pump: A Walbro 255 lph pump ensures enough fuel flow for the increased power level.
  • Boost gauge: Monitoring boost pressure helps you spot boost creep or leaks early.
  • Upgraded intercooler pipes: The factory plastic pipes can crack under higher boost. Silicone or aluminum pipes are a cheap insurance.
  • Clutch: If your stock clutch is old or slipping, the extra torque from the kit will finish it off quickly. Consider a stage 1 or stage 2 clutch.

Long-Term Ownership: Reliability and Maintenance After the Upgrade

When properly installed and tuned, the HKS Super Power Pack does not reduce engine reliability. In fact, many owners report that the improved combustion and reduced detonation risk (thanks to better tuning) can extend engine life compared to running the factory tune with a hard-driven car. Routine maintenance becomes even more important: change oil every 3,000 miles with high-quality synthetic, replace the spark plugs every 15,000 miles (iridium plugs can last longer, but the tune is demanding), and inspect the MAF sensor and air filter every oil change. The HKS filter can be cleaned with a special kit from the brand.

Conclusion

The HKS Super Power Pack remains one of the most cohesive and well-engineered performance kits for the Mitsubishi Eclipse. It eliminates the guesswork of matching parts and provides a reliable, street-friendly power increase that transforms the car’s character. The $1,200-$1,800 price tag for the kit itself may seem steep, but when you factor in the quality of the components, the pre-made ECU tune, and the proven gains, it offers excellent value compared to buying individual parts that may not work together optimally.

Whether you are an experienced home mechanic or prefer to have a shop handle the installation, the key is to start with a healthy engine, follow the instructions carefully, and respect your local emissions laws. After the upgrade, your Eclipse will deliver the kind of responsive, visceral driving experience that makes the legend of the 4G63 endure. For further reading, check out the official HKS Global website and join enthusiast communities like DSMTuners for real-world feedback and support.