The 4G63 engine, found in Mitsubishi's legendary Eclipse, Galant, and Lancer Evolution platforms, is one of the most robust and tunable four-cylinder engines ever produced. For enthusiasts targeting a reliable 450 wheel horsepower, the Garrett GT35R turbocharger remains a gold-standard choice. This upgrade, however, is not simply a bolt-on affair — it requires careful planning, a clear budget, and a deep understanding of supporting modifications. In this comprehensive cost breakdown, we’ll dissect every component, labor hour, and potential pitfall so you can plan your build with confidence. Whether you’re a weekend warrior or a professional shop, this guide covers everything from turbo choice to tuning with real-world price ranges and quality recommendations.

Why the Garrett GT35R for the 4G63?

The Garrett GT35R (part of the GTX series in modern iterations) is renowned for its ability to deliver over 450 hp with exceptional transient response. Its dual ball bearing cartridge and billet compressor wheel allow it to spool quickly while supporting high boost levels. For the 4G63, which thrives on air flow, the GT35R’s 60mm inducer compressor and 68mm turbine wheel provide a perfect balance between street drivability and race-adjacent power. While it can support up to 600 hp, many builders choose it for the 450 hp target because it operates well within its efficiency island, reducing heat and stress on the engine.

Key specifications include:

  • Compressor Trim: 56 trim, 60mm inducer
  • Turbine Wheel: 68mm, 76 trim
  • Housing Options: T3 or T4 flanges, .63 or .82 A/R
  • Oil System: Requires both feed and drain lines with -4AN feed and -10AN drain typical

Choosing a GT35R also gives you the option to upgrade later to a GTX3582R or GTX3576R for higher power levels, preserving your investment in exhaust and intake piping.

Understanding the Complete Build: Beyond the Turbo

A 450 hp 4G63 build using a GT35R is not just a turbo swap — it requires a thorough overhaul of the fuel system, intake, exhaust, engine management, and often the drivetrain. The old adage “you have to pay to play” is especially true here. Below, we break down every cost category with real-world low-end and high-end estimates based on parts from reputable brands like Injector Dynamics, Walbro, Precision Turbo, and Holley.

Turbo System Core Components

1. Garrett GT35R Turbocharger

The heart of the upgrade. New GT35R units range from $1,200 to $1,600 for a genuine Garrett. Used units can be found from $600–$900, but be cautious of worn bearings or shaft play. We strongly recommend purchasing new or from a certified distributor to ensure performance and warranty. Include a turbo blanket ($50–$100) to reduce under-hood heat and improve spool.

  • New Garrett GT35R (T3 .63 A/R): $1,200 – $1,500
  • Turbo Blanket (e.g., DEI): $60 – $100
  • Oil feed line kit (SS braided): $40 – $80
  • Oil drain line and gasket: $20 – $40
  • Water line fittings (if using water-cooled version): $30 – $60

2. Exhaust Manifold

The stock 4G63 manifold is cast iron and can flow enough for 450 hp, but a manifold with a T3 flange and better runner design will improve spool and power consistency. Options range from tubular stainless steel (e.g., Full Race, PTP) to cast iron manifolds like the FP manifold. Budget $400–$900 for a quality piece.

3. Wastegate and Blow-Off Valve

A 38mm or 44mm external wastegate is essential for boost control with the GT35R. A Tial MVR or Turbosmart unit runs $200–$400. For the blow-off valve, a Tial Q or Turbosmart Kompact is typical, costing $100–$200. These components are often included in turbo kits.

4. Intercooler and Piping

450 hp demands an intercooler that can handle roughly 550+ air mass flow. A 4-inch thick core with bar-and-plate design is recommended. Prices for a quality front-mount intercooler kit (e.g., VRSF, CX Racing, Garrett) range from $300–$600. Custom stainless or aluminum piping with couplers and T-bolt clamps adds another $150–$300.

Fuel System Upgrades

The 4G63 factory fuel system cannot sustain 450 hp. You’ll need to replace the injectors, pump, and often the fuel pressure regulator.

  • Fuel Injectors: 1000cc – 1200cc (e.g., Injector Dynamics ID1000, Bosch EV14) – $400–$650
  • Fuel Pump: Walbro 450 LPH or Aeromotive Stealth – $150–$300
  • Fuel Pressure Regulator: Aeromotive A1000 or similar (needed if using return-style system) – $100–$200
  • Fuel Lines and Fittings: -6AN feed, -6AN return, filter – $100–$250

If your 4G63 is in a DSM, you may also need an AFPR (adjustable fuel pressure regulator) setup which can be purchased as a kit for $200–$400. Do not skimp on the pump — the Walbro 255 will barely keep up at 450 hp on E85; a 450 is much safer.

Engine Management and Tuning

Stock ECUs can be reflashed for 450 hp on some DSMs, but for reliability and full control, a standalone ECU is recommended. Options include:

  • ECMLink V3 (DSM-only) – $595 (hardware + software)
  • AEM Infinity 506 (plug-and-play for Evo) – $1,200 – $1,600
  • Haltech Elite 2500 – $1,400 – $2,000
  • Tuning Software/Laptop – often included, but if not, budget $200–$500 for a good wideband and logging license
  • Professional Dyno Tuning – $400–$600 per session (usually 2–3 hours)

A standalone ECU with wideband O2 sensor and MAP sensor can run $1,000–$2,500. If you plan to run E85, factor in a flex fuel sensor ($100–$200).

Cooling and Oil System

High-power 4G63s run hot. Upgraded oil coolers (e.g., Setrab, Earl’s) with thermostat: $200–$400. Cooling system upgrades: larger radiator (Koyo, Mishimoto) $300–$500, and a lower temperature thermostat (180°F) $20–$40. Also consider an oil catch can ($50–$150) to keep the intake clean.

Drivetrain and Supporting Hardware

450 hp will stress stock clutches, axles, and transmissions. While not strictly part of the turbo upgrade, you must budget for:

  • Clutch: ACT 6-puck or South Bend Stage 3 – $400–$800
  • Flywheel: Lightweight (e.g., Fidanza) – $300–$500
  • Differential/Axle upgrades – $500–$1,500 (if you break parts, consider a LSD upgrade)

Labor Costs: DIY vs. Professional Installation

Installing a GT35R and all supporting mods on a 4G63 is a serious job. If you do the work yourself, you save $600–$1,200, but you require mechanical skill, a lift or stands, and specialty tools (torque wrench, O2 sensor socket, fuel line tools). Professional shop labor for a full turbo upgrade (remove stock exhaust manifold, install new turbo, wastegate, intercooler, fuel system, ECU wiring) typically ranges from 8–15 hours at $100–$150/hour = $800–$2,250.

Common tasks and their time estimates:

  • Turbo and manifold swap: 4–6 hours
  • Intercooler and piping: 2–4 hours
  • Fuel system upgrade (pump, lines, injectors): 2–4 hours
  • ECU/wideband wiring: 1–3 hours
  • Testing and initial tuning on boost: 1–2 hours

If you’re building the engine (pistons, rods, bearings) for higher power, add 15+ hours. At 450 hp, a stock 4G63 block with ARP head studs and a metal head gasket is reliable — but a fresh rebuild is recommended for high-mileage engines. That can add $2,000–$4,000 for machine work and parts.

Total Cost Summary Table

Below is a detailed table of all cost categories with low and high estimates. Prices are in USD and reflect new, quality components (mid-tier to premium). Used or budget parts can cut costs 20–40% but carry risk.

ComponentLow EstimateHigh Estimate
Garrett GT35R Turbocharger (new)$1,200$1,500
Turbo Blanket, Lines, Gaskets$150$300
Exhaust Manifold (T3)$500$900
Wastegate + Blow-Off Valve$300$600
Intercooler + Piping Kit$450$900
Fuel Injectors (1000-1200cc)$400$650
Fuel Pump (450LPH)$150$300
Fuel Pressure Regulator + Lines$200$400
Standalone ECU (AEM/Haltech)$1,200$2,000
Wideband + Tuning Software$200$500
Dyno Tuning Session$400$600
Oil Cooler + Thermostat$200$400
Clutch + Flywheel$700$1,300
Labor (Install + Pre-tune)$600$1,200
Total Estimated Cost$7,050$11,850

Note: If you already have a built engine, subtract $1,000–$2,000 for clutch, head studs, etc. The table includes clutch/flywheel as essential for 450 hp.

Hidden Costs and Tips for Saving

Overlooked Expenses

  • Gaskets and Seals: Exhaust manifold gasket, turbo gasket, oil pan gasket if dropping the pan – $50–$100
  • Heat Management: Turbo blanket, wrap for downpipe, insulation for intake piping – $50–$150
  • Intercooler Pipe Couplers – often low quality in budget kits; upgrade to silicone with T-bolt clamps – $50–$100
  • Tools: If you DIY, invest in a turbo stud removal tool, torque wrenches, fuel line disconnect tool – $100–$200
  • Downpipe Modifications: Stock downpipe won’t fit GT35R; a new 3-inch downpipe with V-band or 4-bolt flange is needed – $200–$400
  • Intake Piping and Filter: 4-inch intake to turbo inlet – $50–$150

Cost Reduction Strategies

  • Buy a used turbo in good condition (check for shaft play and seal leaks) – save $300–$500
  • Use a re-flashed stock ECU (ECMLink for DSM) instead of a standalone – save $500–$1,000
  • Install everything yourself – save $800–$2,000 in labor
  • Shop for bracket kits – some vendors sell turbo kits with manifold, downpipe, and intercooler piping as a bundle for $1,500–$2,500
  • Use a budget intercooler (e.g., CX Racing) – save $200, but be aware of core quality

Reliability Considerations at 450 HP

While the 4G63 can handle 450 hp on stock internals, it is on the edge. For consistent 450 hp, consider:

  • ARP Head Studs – $150–$200 (mandatory)
  • Composite Head Gasket – $100–$150 (stock is multi-layer steel, but replace with new)
  • Timing Belt and Tensioner – replace with OEM or Gates racing belt – $150–$300
  • Heat Range Colder Spark Plugs (NGK BR7ES) – $15

If you are confident in your tuning, a stock block can live for many passes. However, for peace of mind, a forged piston and rod upgrade (Mahle, Manley, Eagle) runs $1,500–$3,000 in parts plus $500–$1,000 for machining. That pushes total build cost toward $10,000–$15,000, but it adds a safety margin for 500+ hp later.

Alternatives to the GT35R

The Garrett GT35R is not the only option for 450 hp. Consider these turbos that may offer better spool or value:

  • Precision 5858 Gen2 – smaller frame, faster spool, still hits 450 hp – $1,000–$1,300
  • BorgWarner S362 SX-E – cost-effective, efficient, good for E85 – $800–$1,100
  • Garrett GTX3576R – more modern wheel design, slightly faster spool than GT35R – $1,400–$1,800
  • Holset HX35 (BorgWarner used) – cheap, durable, but larger and slower spool – $200–$500 used

Each has pros and cons; for a street-driven 450 hp goal, the GT35R remains a classic choice because of its proven performance and aftermarket support.

External Resources and Further Reading

To deepen your understanding, visit these authoritative sources:

Final Verdict

A 4G63 turbo upgrade to 450 hp using a Garrett GT35R is a significant but achievable project. The total investment ranges from $7,000 to $12,000 depending on parts quality, labor, and additional drivetrain upgrades. For the enthusiast who values reliability and room to grow, this build offers a thrilling powerband and proven durability. Plan your budget carefully, prioritize supporting mods over flashy parts, and never underestimate the importance of a professional tune. If done right, your 4G63 will reward you with every boost.