Garrett T04 Turbo Upgrade for the Mitsubishi 3000GT: Full Cost, Installation, and Performance Guide

Upgrading the turbocharger on a Mitsubishi 3000GT is one of the most effective ways to unlock serious horsepower and transform the car's personality. Among aftermarket options, the Garrett T04 series stands out as a proven performer that balances spool time with top-end power. This guide covers everything you need to know about swapping a Garrett T04 turbo into your 3000GT, from realistic cost estimates to step-by-step installation procedures and the dyno-proven results you can expect.

Why the Garrett T04 Turbo?

The Garrett T04 turbocharger is a staple in the high-performance community. It uses a T04 compressor wheel paired with a variety of turbine housings, making it adaptable to different engine builds. For the 3000GT, it offers a significant capacity increase over the factory twin-turbo units without requiring a complete engine tear-down. Key characteristics include:

  • Compressor wheel diameters ranging from 50 to 60 trim, allowing you to choose spool vs. top-end
  • Journal bearing or ball bearing options; ball bearing versions offer faster transient response
  • Compatibility with T3 and T4 flanges, meaning you can use off-the-shelf manifolds
  • Support for up to 650+ horsepower when paired with supporting mods

Because the 3000GT VR-4 came with twin turbos, many owners opt for a single turbo conversion. This simplifies the engine bay, reduces weight, and centralizes exhaust flow for better thermal efficiency. The Garrett T04 is an ideal candidate for this swap.

Real Cost Breakdown

Pricing varies widely based on turbo specifications, sourcing (new vs. rebuilt), and whether you perform the labor yourself. Here's a realistic breakdown for a complete single T04 conversion on a 3000GT:

  • Garrett T04 turbo (new, journal bearing): $950 – $1,400
  • Turbocharger rebuild kit / CHRA cartridge (if rebuilding used unit): $150 – $350
  • Single turbo manifold (custom or premade): $400 – $800
  • Downpipe and exhaust modifications: $200 – $500
  • Intercooler and charge piping kit: $500 – $1,200
  • Oil feed and drain line kit: $80 – $180
  • Boost controller (manual or electronic): $50 – $250
  • Blow-off valve: $80 – $200
  • ECU tuning (e.g., FlashPro, standalone, or chip tune): $500 – $1,200
  • Miscellaneous gaskets, clamps, hardware: $100 – $200
  • Labor if hiring a shop (estimate 12–20 hours): $1,200 – $2,400

Total DIY cost range: approximately $2,800 – $5,400. A turnkey shop install may run $4,000 – $7,500 or more, depending on tuning complexity. Budget extra for unexpected items like broken studs or wiring issues.

Essential Tools and Workspace Preparation

Before you start wrenching, gather the right equipment. The 3000GT's engine bay is tight, and a turbo swap requires patience. Here's what you'll need:

  • Socket set with metric sizes (8mm to 22mm), preferably deep sockets for hard-to-reach nuts
  • Torque wrench rated for 10–80 ft-lbs for critical fasteners
  • Set of combination wrenches and ratcheting wrenches for exhaust manifold bolts
  • Breaker bar (18–24 inches) for stubborn exhaust nuts
  • Pry bars and gasket scrapers to separate old flanges
  • Jack stands and floor jack – the car needs to be safely elevated for undercarriage work
  • Safety glasses, gloves, and fire extinguisher – working with fuel and oil lines demands caution

Ensure you have a clean, well-lit workspace. Many 3000GT owners find it easier to remove the front bumper and radiator support for extra clearance during a single turbo conversion.

Step-by-Step Installation Process

The following outlines the general sequence for removing the factory twin turbo setup and installing a Garrett T04-based single turbo. Always refer to your specific turbo kit instructions and factory service manual for torque specs.

Step 1: Safety and Preparation

  • Disconnect the battery negative terminal. This is critical – the 3000GT has many electronic systems that can short if power is accidentally applied.
  • Drain the engine oil and coolant to prevent spills when removing oil lines and water lines.
  • Remove the intercooler piping, intercooler itself, intake pipe, and air filter box for clear access to the turbos.

Step 2: Remove the Factory Twin-Turbo Setup

  • Disconnect the oil feed lines and return lines from both factory turbos. Have rags handy – residual oil will drip.
  • Unbolt the exhaust downpipes from the turbo outlets. You may need to soak the nuts in penetrating oil beforehand.
  • Remove the heat shields covering the exhaust manifolds and turbos.
  • Unbolt the exhaust manifolds from the cylinder heads. The rear manifold is particularly tight; consider removing the EGR system if still present for easier access.
  • Extract the two factory turbos and manifolds as an assembly if possible, then separate them on the bench.

Step 3: Modify Engine Bay for Single Turbo

  • Install the new single turbo manifold onto the passenger side (right bank) exhaust ports. Many conversions use a manifold that connects both cylinder banks and routes through a single flange. Ensure gasket surfaces are clean.
  • Block off the unused cylinder head exhaust ports on the driver's side (left bank) using block-off plates, or install a bridge pipe that merges both headers into one collector. Some kits provide a crossover pipe.
  • Re-route or delete the water lines that originally cooled the turbos. The Garrett T04 may be oil-cooled only, depending on your model.

Step 4: Mount the Garrett T04 Turbo

  • Attach the turbo to the manifold using the supplied gasket and bolts. Tighten evenly in a crisscross pattern to 45–55 ft-lbs (or as specified).
  • Clock the compressor and turbine housings as needed to align oil drain and charge pipe ports. Mark the positions.
  • Install the oil feed line from the engine's oil filter housing adapter to the turbo oil inlet. Use a restrictor if your turbo requires one (common with journal bearing T04s).
  • Connect the oil drain line from the turbo's bottom to the oil pan. Drill and weld a return bung into the pan if your kit doesn't include a pre-existing port.

Step 5: Charge Piping and Intercooler

  • Mount the intercooler (bar-and-plate style recommended). Most owners use a front-mount intercooler mounted behind the front bumper.
  • Route charge pipes from the turbo compressor outlet through the intercooler and into the throttle body. Use silicone couplers and T-bolt clamps to prevent blow-off at high boost.
  • Install a blow-off valve on the charge pipe between the intercooler and throttle body.

Step 6: Exhaust and Reassembly

  • Attach the downpipe to the turbo turbine outlet. A 3-inch downpipe is recommended to reduce backpressure.
  • Reinstall the radiator, fan shroud, and front bumper. Check clearance – the single turbo and charge pipes should not contact the radiator core.
  • Refill engine oil and coolant. Prime the turbo by pouring clean oil into the feed line before starting the engine.
  • Reconnect the battery and check for loose wires, hoses, or tools left in the engine bay.

Post-Installation Checks and Tuning

After physically installing the turbo, you must verify the system before driving. Here are critical checks:

  • Oil leaks: Run the engine briefly with the car on jack stands. Look for dripping at the oil drain flange, oil feed line fittings, and exhaust manifold gaskets.
  • Coolant system: If you retained water lines, check for leaks. Burp the cooling system to remove air pockets.
  • Boost leaks: Use a DIY boost leak tester (a PVC cap with an air fitting) to pressurize the charge system to 15–20 psi. Listen for hisses at couplers, intercooler end tanks, and blow-off valve.
  • Fuel system upgrade: A Garrett T04 at stock fuel pressure will quickly max out factory injectors. Install 550cc–850cc injectors and a higher-flow fuel pump (Walbro 255 LPH or equivalent).
  • ECU calibration: The stock ECU cannot adjust for the massive airflow increase. You must use a standalone ECU (e.g., Haltech, AEM, or MoTeC) or a reflash/upgrade chip. Professional dyno tuning is strongly advised to set air-fuel ratios and ignition timing safely.
  • Break-in procedure: Drive the car gently for the first 200 miles, varying RPM and avoiding sustained high boost. This seats the piston rings (if you rebuilt the engine) and allows the turbo seals to settle.

Expected Performance Results

When properly tuned, a Garrett T04 turbo on a 3000GT VR-4 delivers transformative gains. On a stock 3.0L 6G72 engine with moderate supporting mods (intercooler, fuel system, exhaust), expect:

  • Wheel horsepower: 450–520 whp on pump gas (93 octane) at 18–22 psi boost
  • Torque: 450–540 lb-ft, peaking in the midrange (3,500–5,000 RPM)
  • 0–60 mph: 3.5–4.0 seconds (with proper traction)
  • Quarter-mile: Low 11s to high 10s, depending on chassis setup and tires

With a built bottom end, upgraded cams, and higher boost (25–30 psi using race fuel or E85), the same turbo can push 600+ whp. The T04's compressor map shows strong efficiency in the 35–55 lb/min airflow range, making it well-suited to the 3.0L displacement.

One trade-off: spool characteristics change. A T04E 60-trim spools later than the small factory twins. Full boost arrives around 3,800–4,200 RPM instead of 2,800 RPM. This moves power higher in the rev range but reduces low-RPM laziness, rewarding a more aggressive driving style. You can improve spool by selecting a divided turbine housing and using a twin-scroll header.

Common Pitfalls and How to Avoid Them

Many first-time 3000GT single turbo encounters suffer the same mistakes. Here's what to watch for:

  • Choosing too large a turbo: A T04Z or T04R with a massive compressor wheel will push the airflow beyond the engine's ability to ingest it, creating lag and heat. Stick to T04E 50- or 60-trim for a responsive street car.
  • Overlooking backpressure: A restrictive stock exhaust or small downpipe negates turbo gains. Use 3-inch mandrel-bent piping.
  • Oil supply issues: If the oil feed is too high pressure (stock engine pressure can exceed 70 psi hot), the turbo's journal bearings may leak. Use a feed restrictor or a pressure regulator.
  • Ignition system strain: Higher cylinder pressures require stronger spark. Upgrade to NGK BPR9ES plugs gapped to 0.028 inches and consider a modern coil-on-plug setup.
  • Tuning delays: Running the car without proper tuning risks detonation and engine failure. Don't drive even a few miles without a base map from an experienced tuner.

External Resources for a Successful Build

To learn more about Garrett turbo maps and 3000GT-specific installation tips, refer to these resources:

Final Considerations

Installing a Garrett T04 turbo in your Mitsubishi 3000GT is a major project but one that rewards with thrilling performance. The key to success lies in careful planning: select components that match your power goals, budget for tuning, and verify every seal and clamp before hitting the road. Once dialed in, a single T04 3000GT becomes a true high-performance machine capable of holding its own against modern sports cars while retaining the raw character of the '90s supercar.