Upgrading the turbocharger on a Mitsubishi Eclipse GSX (2G DSM) is one of the most effective ways to unlock serious horsepower. The factory TD05-14B turbo is capable, but the AMS T28 turbo offers a direct bolt-on upgrade that flows more air and supports higher boost levels while maintaining quick spool. This guide walks through the complete installation process, including preparation, removal, and installation, with professional tips to avoid common pitfalls.

Step 1: Preparation – Tools, Parts, and Workspace

Proper preparation prevents delays and damage. Before touching a wrench, gather every component and tool you’ll need. The AMS T28 turbo kit is designed as a direct replacement for the stock 2G DSM turbo, but supporting modifications (fuel system, intercooler, tuning) may be required for safe operation at elevated boost levels.

Required Parts and Components

  • AMS T28 turbocharger – includes turbo, actuator, oil feed line, oil drain gasket, and crush washers
  • New gaskets – turbo-to-manifold, turbo-to-O2 housing, oil return gasket
  • Oil feed line – stainless steel braided recommended; AMS kit usually includes one
  • Oil drain line – stock can be reused if in good condition, but a new o-ring or gasket is wise
  • Coolant lines – stock lines can be reused, but consider replacing rubber sections with silicone for durability
  • Boost control accessories – manual boost controller or electronic boost controller, vacuum lines (4mm silicone)
  • Boost gauge (already fitted) – mandatory for monitoring
  • Fresh engine oil and coolant – top off after installation

Essential Tools

  • Socket set (metric: 10mm, 12mm, 14mm, 17mm, 19mm)
  • Combination wrenches (same sizes)
  • Torque wrench (ft‑lb and in‑lb ranges)
  • Flathead and Phillips screwdrivers
  • Pliers (needle‑nose and slip‑joint)
  • Gasket scraper or razor blade
  • Penetrating oil (WD‑40 or PB Blaster)
  • Jack and jack stands (for access)
  • Rag or shop towels
  • Safety glasses and gloves

Workspace and Safety

Work in a well‑ventilated area with the vehicle on level ground. Disconnect the battery negative terminal before starting. Allow the engine to cool completely – working on a hot exhaust manifold increases burn risk and makes fasteners more likely to snap. If the car has been driven recently, wait at least an hour.

Performance tip: The AMS T28 can safely support 350–400 whp when paired with proper fuel upgrades (650cc+ injectors, fuel pump) and engine management (ECMLink or standalone). Verify your fuel system is capable before winding up boost.

Step 2: Removing the Factory Turbocharger

Removing the stock TD05‑14B is straightforward but requires patience. Many bolts are in tight spots, and corrosion is common on older 4G63 engines. Use penetrating oil on exhaust manifold bolts and O2 housing bolts at least 15 minutes before wrenching.

Disconnect Intake and Exhaust Components

  • Remove the intake pipe and air filter assembly from the turbo inlet.
  • Unclip the recirculation hose if you have a blow‑off valve.
  • Unbolt the O2 housing from the downpipe (three 14mm nuts on 2G).
  • Disconnect the front O2 sensor harness (if still present).

Drain Coolant and Oil Lines

Place a drain pan under the turbo area. Loosen the banjo bolts on the oil feed line (17mm or 19mm) and the coolant lines (12mm or 14mm). Be prepared for some fluid spillage. Remove both coolant lines from the turbo – the stock lines are stiff and may require gentle persuasion. Label which line goes where to avoid confusion during reassembly.

Remove the oil return line from the turbo to the oil pan. The return line uses a 10mm or 12mm bolt; the gasket often sticks and may need scraping. Replace the return line gasket even if it looks reusable.

Unbolt the Turbo from the Exhaust Manifold

  • Support the turbo from underneath to prevent stress on the manifold studs.
  • Remove the four (or five) nuts holding the turbo to the exhaust manifold. Use a deep socket and a swivel extension for the lower left nut – it’s the most awkward.
  • Separate the turbo from the manifold. Gently tap with a rubber mallet if stuck. Never pry against the manifold gasket surface.

Once free, lower the turbo out of the engine bay through the bottom or top depending on clearance. On a 2G, removal through the top is possible after loosening the engine mount or removing the intercooler pipe. Many DSMs require removing the driver‑side engine mount bracket for easiest access.

Inspect and Clean Mounting Surfaces

With the old turbo out, clean the exhaust manifold and O2 housing flanges with a gasket scraper and brake cleaner. Remove any remaining gasket material. Check the manifold for cracks – a cracked manifold can cause boost leaks and poor spool. Inspect the oil drain tube for debris; clean it with a pipe cleaner if needed.

Pro tip: Replace all turbo gaskets and crush washers – reusing old gaskets is a guaranteed oil leak. Use OEM or Fel‑Pro gaskets for best sealing.

Step 3: Installing the AMS T28 Turbocharger

The AMS T28 is designed to be a near‑direct bolt‑on, but careful attention to oil and coolant routing is critical. Follow these steps sequentially to avoid mistakes.

Pre‑Install Oiling

Before mounting the turbo, prime the bearing section. Pour a few ounces of clean engine oil into the oil feed port while spinning the compressor wheel by hand. This lubricates the bearings before startup and prevents dry initial run damage. Do not use WD‑40 or assembly lube – engine oil only.

Mount the Turbo to the Exhaust Manifold

  • Place a new turbo‑to‑manifold gasket on the manifold studs.
  • Lift the AMS T28 into position. Align the oil drain flange to point downward at the same angle as the stock drain line.
  • Thread the manifold nuts by hand, then tighten in a criss‑cross pattern to 30–35 ft‑lbs (check manufacturer specs).

If the turbo doesn’t sit flush, rotate the compressor housing slightly – the AMS T28 allows clocking of the center section. The compressor outlet should face the intercooler piping, typically toward the front of the car.

Connect Oil Feed and Drain

  • Install the new oil feed line using the supplied banjo bolt and new crush washers. Torque to 15–20 ft‑lbs – overtightening can crush the washers and cause leaks.
  • Attach the oil drain tube with a new gasket. The drain must flow downward by gravity; any upward slope can cause oil backup and turbo seal failure. Verify the drain angle before tightening all bolts.

Connect Coolant Lines

Reattach the two coolant lines to the turbo. Use new crush washers on the banjo fittings. Coolant flow direction matters – the supply (from the water pipe) goes to the lower port, and return goes to the upper port (or as marked). Refer to AMS instructions; incorrect routing can cause air pockets and overheating.

Tighten banjo bolts to 20–25 ft‑lbs. Do not overtorque the coolant barbs – they are brass and can strip.

Install O2 Housing and Exhaust Components

  • Attach the O2 housing with a new gasket. Torque the three nuts to 35–40 ft‑lbs.
  • Reconnect the downpipe to the O2 housing.
  • Reinstall the front O2 sensor into the O2 housing.

Reconnect Intake and Accessories

  • Attach the intake pipe to the turbo inlet. Use a new silicone coupler if the stock one is hard or cracked.
  • Connect the recirculation hose from the blow‑off valve to the intake pipe.
  • Install the boost control solenoid or manual boost controller into the vacuum line between the compressor outlet and the wastegate actuator. The AMS T28 has an adjustable actuator; set it to the desired base boost (usually 12–15 psi before adding a controller).

Final Checks and First Start

Double‑check all connections: oil feed and drain, coolant lines, intake and exhaust, and electrical connectors (O2 sensor, MAF, etc.). Ensure nothing is loose or rubbing against the turbo hot side. Refill coolant and top off engine oil. Reconnect the battery negative terminal.

Start the engine and let it idle for 10–15 seconds, then shut it off. Check for oil leaks around the feed line, drain line, and banjo bolts. Restart and let the engine reach operating temperature. Listen for unusual noises – a whine or grating sound indicates a problem. Watch the boost gauge during a gentle test drive; set base boost and fine‑tune with the controller.

Additional Considerations for a Successful T28 Upgrade

Fuel System Upgrades

The T28 flows roughly 35–40 lb/min, supporting up to 350–400 hp on pump gas. At boost levels above 15 psi, stock 450cc injectors and the 2G fuel pump become marginal. Install at least 550cc or 650cc injectors and a Walbro 255 lph fuel pump. Tune with ECMLink or a standalone ECU to dial in air/fuel ratios.

Intercooler and Piping

The stock side‑mount intercooler is a bottleneck. A front‑mount intercooler (FMIC) kit greatly reduces intake air temperatures and supports higher boost. Many FMIC kits for the 2G DSM include piping that mates to the AMS T28 compressor outlet.

Tuning and Boost Management

A manual boost controller is the simplest way to raise boost, but an electronic boost controller (e.g., AEM or TurboXS) offers in‑cabin adjustability. Always use a quality wideband O2 sensor and boost gauge to monitor during tuning. Start conservative and increase boost gradually while watching knock counts.

Common Pitfalls and How to Avoid Them

  • Oil leaks at drain flange – always replace the drain gasket and ensure the drain line is not kinked or angled upward.
  • Coolant leaks at banjo bolts – use new crush washers each time. Overtightening crushes them, causing leaks.
  • Boost creep – the T28’s actuator may not control wastegate flow at high boost. Port the wastegate passage or use an external wastegate if creep persists.
  • Damaged compressor wheel – any debris entering the intake can destroy the blades. Use a clean air filter and ensure intake piping is debris‑free.

Performance Expectations

With proper supporting mods and tuning, an AMS T28 on a Mitsubishi Eclipse GSX can produce 350–400 whp and 350 ft‑lbs of torque. Spool is near stock – full boost by 3200–3500 RPM – making it a fantastic street upgrade. The car feels significantly faster from any speed, with strong mid‑range pull.

For further reading on DSM turbo upgrades, consult AMS Performance for product details and DSMTuners for community tips and tuning guides. Additional sourcing for supporting parts can be found at ExtremePSI and StreetTuned Motorsports.

Conclusion

Installing an AMS T28 turbo in a Mitsubishi Eclipse GSX is a rewarding project that drastically improves power without requiring a full engine build. By meticulously gathering the correct tools and parts, carefully removing the factory turbo, and methodically installing the AMS unit with attention to oil and coolant lines, you can complete the swap in a single weekend. Follow all torque specifications, use new gaskets and crush washers, and invest in tuning and fuel upgrades to realize the turbo’s full potential. The result is a responsive, powerful daily driver or weekend track car that lives up to the GSX legacy.