Introduction

The 1G DSM Eclipse (1990–1994) remains a beloved platform for enthusiasts thanks to its robust 4G63 engine and turbocharged potential. One of the most cost-effective and impactful upgrades is a high-flow intake system like the HKS Super Power Flow. This kit replaces the restrictive factory airbox with a large conical filter and smooth aluminum pipe, reducing intake restriction and increasing throttle response. Proper installation is critical—a poorly fitted intake can trigger check engine lights, cause rough idles, or even suck in unfiltered air. This guide covers every step in detail, from tool preparation to post-install tuning, so you can extract maximum performance from your 1G Eclipse.

Tools and Materials

Before starting, gather everything you need. Having the right tools prevents frustration and ensures a clean installation.

Required Items

  • HKS Super Power Flow intake kit – specific to 1G Eclipse (part number 1505-SP016 or equivalent). Confirm the kit includes the air filter, intake pipe, clamps, and mounting bracket.
  • 10mm, 12mm, and 14mm sockets with a ratchet and extension
  • Flathead and Phillips screwdrivers
  • Needle-nose pliers – for hose clamps
  • Torque wrench (ft-lb and in-lb scales) – optional but recommended for clamp and bolt torque
  • Rags and brake cleaner – for cleaning intake port and throttle body
  • Safety glasses and mechanic’s gloves

Optional but Helpful

  • Jack stands and a floor jack – if you need to remove the splash shield for easier access
  • Dielectric grease – for MAF sensor connector pins
  • Foam filter oil (if using a pleated cotton filter that requires oiling)
  • Smoke machine or carburetor cleaner – for post-install leak testing

Preparation and Safety

Work on a level surface with the engine completely cold. Disconnect the negative battery terminal to prevent accidental sparking or ECU damage while handling electrical connectors. If your car has aftermarket modifications (e.g., larger turbo, blow-off valve), verify the intake path will not interfere with other components. Lay a drop cloth under the engine bay to catch dropped bolts or debris.

Critical Safety Checks

  • Remove any loose jewelry or clothing that could catch in belts or fans.
  • Secure the hood with its prop rod – do not rely on gas struts if they are weak.
  • If the vehicle has been driven recently, allow the intake manifold and turbo heat shield to cool for at least 30 minutes.

Removing the Stock Air Intake

The factory intake system on a 1G Eclipse consists of an airbox, a rubber intake hose, a resonator, and a mass airflow sensor. Removing it correctly prevents damage to fragile components like the MAF sensor.

Step 1: Disconnect the MAF Sensor

Locate the Mass Airflow Sensor on the intake pipe between the airbox and the turbo inlet. Squeeze the connector tab and pull gently to separate. Do not pull on the wires. Set the connector aside where it won’t be pinched.

Step 2: Remove the Intake Hose and Clamps

Use a flathead screwdriver to loosen the worm‑drive clamp at the turbo inlet and the clamp at the airbox outlet. If the hose is old and stiff, carefully work it free with a twisting motion. Do not pry directly against the turbo inlet flange – it can crack.

Step 3: Unbolt the Airbox

The airbox is held by three 10mm bolts – two on top of the fender well and one below near the inner fender liner. A short extension and ratchet make these easier to access. Lift the airbox out, being careful not to drop debris into the open turbo inlet. Also remove any intake resonator tubing that runs into the bumper (often secured with a 10mm bolt and a plastic push‑pin).

Step 4: Inspect and Clean

With the stock intake removed, inspect the turbo inlet for any loose debris, oil, or damaged o‑rings. Wipe the inside of the turbo inlet with a clean rag and a small amount of brake cleaner. If you see heavy oil deposits, consider cleaning the intercooler piping as well – a clogged intercooler will negate gains from the new intake.

Installing the HKS Super Power Flow

Now the actual upgrade begins. The HKS Super Power Flow kit for the 1G Eclipse is designed to bolt directly to the turbo inlet using a special silicone coupler and aluminum adapter. Follow the kit’s included instructions, but the general procedure is as follows.

Step 1: Mount the Bracket

Most HKS kits include a metal bracket that bolts to the old airbox mounting points or to the inner fender. Use the provided hardware to attach the bracket. Torque the bolts to 8‑10 ft‑lb – overtightening can strip the thin sheet‑metal threads.

Step 2: Install the Adapter Pipe and MAF Housing

The intake pipe has a smooth section where the MAF sensor mounts. Slide the MAF into the housing and secure it with the included screws (if any). Ensure the MAF’s direction arrow points toward the turbo – installing it backward will cause incorrect airflow readings and a check engine light.

Step 3: Attach the Intake Pipe to the Turbo Inlet

Place the silicone coupler on the turbo inlet. Slide the intake pipe into the coupler and tighten the clamp to 3‑4 ft‑lb (do not overtighten – silicone can tear). Confirm the pipe does not contact the radiator fan, hood, or any moving parts. Reposition the pipe slightly if needed.

Step 4: Fit the HKS Air Filter

The conical filter attaches directly to the end of the intake pipe using a large worm‑drive clamp. Position the filter so it sits away from the engine’s heat sources – ideally in the space behind the headlight or inside a custom cold‑air box. Tighten the clamp securely but not to the point of distorting the filter flange.

Step 5: Reconnect the MAF Connector

Plug the MAF sensor connector back in. Apply a small amount of dielectric grease to the pins to prevent corrosion. Ensure the wiring harness is routed away from the intake pipe – heat and vibration can damage wires over time.

Final Checks and First Start

Before starting the engine, perform a thorough inspection. A small mistake now can lead to drivability issues or engine damage.

Visual Inspection List

  • All clamps are tight – check both the turbo inlet coupler and the filter clamp.
  • No loose bolts or tools left in the engine bay.
  • The intake pipe does not touch the radiator fan shroud or the hood – close the hood gently and check clearance.
  • All vacuum lines are reconnected (if any were removed).
  • The battery negative terminal is reconnected.

Idle Procedure

Turn the key to the ON position (do not start) – wait for the fuel pump to prime (3‑5 seconds). Then start the engine. Let it idle for 1‑2 minutes while checking for:

  • Unusual whistling or sucking sounds – these indicate an air leak.
  • Check engine light – if it appears, stop the engine and recheck MAF connections.
  • Steady idle near 750‑850 rpm (warm) – if the idle is erratic, there may be a vacuum leak.

Testing and Tuning

A fresh intake installation can cause the ECU to adapt its fuel trims – this is normal. However, you should verify the system is working correctly.

Short Drive Test

Take the car for a 15‑minute drive using varying loads: gentle cruising, moderate acceleration, and a few full‑throttle pulls in second and third gear (on a safe road). Pay attention to:

  • Throttle response – it should feel sharper than before.
  • Any hesitation or stumbling – could indicate a MAF signal issue.
  • Boost gauge behavior – with less restriction, the turbo may spool slightly faster.

Scan for Diagnostic Trouble Codes

If the check engine light illuminates, use an OBD‑I scanner (or a paperclip trick for the 1G) to retrieve codes. Common codes after an intake swap include P0100 (MAF circuit) or P0505 (idle control system). Most of these are caused by loose connections or a small vacuum leak. Fix any codes before driving aggressively.

Maintenance

The HKS Super Power Flow filter requires periodic cleaning to maintain airflow. Neglect can lead to a dirty filter that strangles performance.

  • Inspect the filter every 5,000 miles – remove the filter and hold it up to the light. If it appears dark and clogged, clean it.
  • Cleaning process: Use an HKS filter cleaner (or a gentle soap solution) and rinse with low‑pressure water. Let it air‑dry completely (24 hours). If the filter is oiled type, re‑apply a thin coat of filter oil – do not oversaturate.
  • Check clamp tightness every 10,000 miles – vibration can loosen worm‑drive clamps over time.
  • Replace the filter every 50,000 miles or sooner if it shows signs of tearing.

Troubleshooting Common Issues

Even a well‑installed intake can cause issues in some cases. Here are solutions to the most frequent problems.

Rough Idle or Stalling

  • Check for unmetered air leaks: spray a small amount of carb cleaner around the couplers and MAF housing – if the idle changes, you have a leak. Tighten clamps or reseat the coupler.
  • Ensure the MAF sensor is clean – oil from a new filter can coat the sensor wire. Use MAF cleaner spray (not brake cleaner) to clean it gently.

Check Engine Light (P0100/P0101)

  • Verify the MAF connector is fully seated and the pins are not bent.
  • Confirm the MAF is oriented correctly – the arrow must point toward the turbo.
  • If using a translator (e.g., MAF‑Translator), recheck programming settings.

Filter Sucks Closed or Collapses

  • This rarely happens with HKS filters, but if you see a cone filter collapse under high boost, the filter element may be clogged, or the spring support is damaged. Replace the filter.

Turbo Surge or Compressor Stall

  • An extremely free‑flowing intake can sometimes shift the compressor map and cause surge on stock turbos. If you hear a fluttering sound on deceleration, consider a blow‑off valve or recirculation setup. This is not harmful, but it may be annoying.

Performance Expectations

With the HKS Super Power Flow correctly installed, you can expect gains of 5‑10 horsepower on a stock 4G63, with most of the improvement felt in mid‑range throttle response. The intake also produces a deeper induction sound that many enthusiasts find addictive. Peak boost levels typically remain unchanged, but spool time can decrease by 200‑300 rpm.

For maximum gains, pair the intake with a free‑flowing exhaust and a boost controller. Many 1G owners report that the combination of the HKS intake and a 2.5” downpipe yields the best cost‑per‑horsepower upgrade. Check resources like DSMTuners installation guides or Magnus Motorsports tuning guides for advanced setup tips.

Conclusion

Installing the HKS Super Power Flow on your 1G Eclipse is a rewarding project that improves both performance and sound. By following the detailed steps outlined here – from proper removal of the stock intake to final leak checks and maintenance – you can complete the job in under two hours with basic hand tools. Remember that attention to detail during installation prevents drivability headaches down the road. Enjoy the newfound responsiveness and the iconic HKS whistle.