Understanding the FA20 Subaru WRX Turbo Kit Components

The FA20 Subaru WRX, introduced in 2015, quickly became a favorite among enthusiasts for its responsive direct-injection boxer engine and immense tuning headroom. While the factory turbocharger delivers respectable performance, upgrading to an aftermarket turbo kit unlocks significantly higher power levels—often reaching 350–500 horsepower with proper supporting modifications. However, a turbo kit is not a single component; it is an integrated system. Each part serves a critical function, and quality variations directly affect the total price.

Before diving into costs, let’s break down the core components of a complete turbo kit for the FA20 WRX:

  • Turbocharger: The heart of the system. Aftermarket options range from smaller “stage 1” units that spool quickly to large frame turbos capable of 50+ psi. Common choices include Garrett, BorgWarner, and Mitsubishi derived units. Price correlates with size, material (cast vs. billet), and brand reputation.
  • Exhaust Manifold: Directs exhaust gases from the engine to the turbo. FA20s typically use a twin-scroll manifold design to reduce lag. Aftermarket manifolds can be log style, equal-length, or unequal-length, affecting spool characteristics and sound. Stainless steel or cast iron are common materials.
  • Wastegate: Controls boost pressure by diverting exhaust flow away from the turbine wheel. Internal wastegates are simpler and cheaper, but high-horsepower builds often require an external wastegate for more precise control and higher flow capacity. Prices vary by size (e.g., 38mm vs. 45mm) and brand.
  • Intercooler: Cools compressed intake air before it enters the engine. For the FA20, front-mount intercoolers (FMIC) are the norm for upgraded turbos, offering much larger core volume than the factory top-mount (TMIC). Bar-and-plate cores provide superior heat dissipation compared to tube-and-fin designs.
  • Blow-Off Valve (BOV): Relieves pressure in the intake system when the throttle closes. Recirculating (plumb-back) valves are preferred for driveability, but atmospheric BOVs offer a louder sound. Adjustable springs are needed for higher boost levels.
  • Piping and Hoses: Includes intake piping from filter to turbo, charge pipes from turbo to intercooler, and from intercooler to throttle body. Aluminum or silicone hoses with high-temperature resistance. Couplers and clamps must handle up to 60 psi pressures.
  • Fuel System Modifications (often sold separately): While not always included in a basic turbo kit, upgrading injectors, high-pressure fuel pump (HPFP), and fuel lines is mandatory when exceeding 400 whp. The FA20’s direct injection system can run out of flow capacity at high boost.
  • Engine Management / Tuning Solution: A turbo kit is useless without proper calibration. Options include a custom ECU flash (Cobb Accessport, EcuTek), piggyback controllers, or standalone ECUs (e.g., Motec, Link). Tuning also requires time on a dynamometer.

Most turbo kits are sold as either “stage kits” (complete with turbo, manifold, wastegate, piping, and intercooler) or “custom build” (components selected individually). The price difference between these approaches can be substantial.

Detailed Cost Breakdown for an FA20 WRX Turbo Kit

The total investment for a turbocharger upgrade on a FA20 WRX varies from around $3,000 for a modest “stage 2” style kit to over $10,000 for a high-end, fully fabricated setup. Below is a realistic cost range for each major component, based on current market data and installers’ average quotes.

Core Turbo Kit Components

  • Turbocharger: $1,200 – $4,500 (e.g., Cobb SF Turbo: $1,500; Garrett GTX3076R: $2,200; BorgWarner S366 SXE: $1,800; Precision 6266: $2,500)
  • Exhaust Manifold: $400 – $1,200 (equal-length stainless: $600; twin-scroll cast: $800; custom header: $1,200+)
  • Wastegate (external): $250 – $700 (Tial 38mm: $350; Turbosmart 45mm: $500; COBB 50mm: $600+)
  • Intercooler: $500 – $1,500 (process west verticooler: $1,200; ETS 3.5” FMIC kit: $1,400; custom core: $800)
  • Blow-Off Valve: $150 – $400 (Tial Q: $350; HKS SSQV: $250; TurboXS hybrid: $200)
  • Piping Kit (charges & intake): $300 – $800 (aluminum mandrel bent: $400; silicone coupler set: $150; complete charge pipe kit: $600)
  • Oil/Coolant Lines: $100 – $300 (braided stainless feed/drain lines)
  • Gaskets, Fasteners, & Misc Hardware: $50 – $150

Subtotal for core kit (excluding fuel & tuning): approximately $3,000 – $9,500

Supporting Modifications (Often Required)

  • High-Flow Fuel Injectors (if DI limitation): $600 – $1,500 (e.g., Injector Dynamics 1050x: $800; Fuel Injector Clinic: $1,200)
  • Upgraded High-Pressure Fuel Pump (HPFP): $700 – $1,200 (e.g., Nostrum HPFP: $1,100; OEM upgraded internals: $700)
  • Fuel Pressure Regulator & Lines: $200 – $500
  • Engine Management (Cobb Accessport V3): $650 – $1,000 (new) + $300 – $700 for a custom e-tune or dyno tune
  • Clutch Upgrade (for >400 whp): $500 – $1,800 (e.g., ACT HD: $600; Exedy Twin: $1,500)
  • Interior Monitoring (Boost gauge, AFR gauge): $200 – $600

Total estimated range for a streetable 400–450 whp build: $5,500 – $12,000

Installation labor adds significant cost. A professional shop typically charges $80 – $150 per hour for labor, with most turbo-upgrade installs requiring 20–40 hours depending on the kit complexity and additional work. That translates to $1,600 – $6,000 in labor alone. A DIY installation saves this but requires specialized tools and experience.

Factors That Influence the Final Price

Several variables push the actual cost of a WRX turbo kit above the base component prices. Understanding these factors helps you budget realistically.

1. Turbocharger Size and Technology

Smaller turbos (like a Garrett GT2860RS or BorgWarner EFR 6758) cost less but may not require as many supporting modifications. Larger turbos (GTX3586R, Precision 6870) demand upgraded fuel systems, bigger intercoolers, and stronger clutches, rapidly inflating the total bill. Additionally, ball-bearing turbochargers (e.g., Garrett, BorgWarner EFR) offer better spool but cost $300–$600 more than journal-bearing equivalents.

2. Manifold Design

Equal-length manifolds provide the best flow and power up top but can cost $800+. Unequal-length manifolds, popular for the Subaru rumble, are less efficient at high RPM and may be cheaper ($400–600). Twin-scroll manifolds, which help with spool, are complex to fabricate and often priced higher.

3. Intercooler Configuration

Front-mount intercoolers require cutting the bumper beam or crash bar, which adds labor and potential bodywork costs. Some kits include a crash bar replacement. Larger cores (4” thick vs. 3”) increase cooling but also cost more. The route of the piping (hot-side vs. cold-side mount) can necessitate custom fabrication.

4. Tuning and Dyno Time

A proper tune is mandatory. Many enthusiasts opt for a “e-tune” (email-based tuning with data logs) costing around $250–$500, but a dyno tune by a respected tuner runs $500–$1,000 for a complete session. If the tune is not done correctly, engine damage is likely, so this is not an area to cut costs.

5. Labor and Shop Location

Hourly rates vary by region: $90–$120/hr in the Midwest, $130–$170/hr on the coasts. Shops specializing in Subaru performance often have surcharges but do the job correctly. Expect a $1,500–$4,000 labor bill for a full install. Fabrication work (custom piping, welding, relocation of parts) adds $500–$2,000 more.

6. Brand and Warranty

Respected brands like COBB Tuning, Grimmspeed, and Full-Race offer comprehensive kits with tested parts, but their prices reflect R&D and customer support. Budget brands from eBay may cost 40% less but often require significant modifications, poor fitment, and lower durability—potentially costing more in the long run.

Additional Modifications You May Not Have Considered

Beyond the obvious turbo components, several other modifications become necessary once you increase boost significantly on the FA20:

Fuel System Upgrades

The stock fuel system on the FA20 WRX becomes a bottleneck around 400 whp. The direct injection high-pressure fuel pump cannot supply enough fuel for sustained high boost. Aftermarket HPFPs (e.g., Nostrum, XDI) cost $1,000+. Additionally, port injection is sometimes added to supplement fuel flow, requiring a secondary fuel rail, injectors, and a controller (e.g., Injector Dynamics, Split Second). This can add $1,500–$3,000 more.

Clutch and Flywheel

At 400+ whp, the stock clutch will slip. A stage 2 or stage 3 clutch kit (e.g., ACT, Exedy, South Bend) is essential. A single-mass flywheel reduces rotational inertia for quicker revs but may increase gear noise. Budget $600–$1,800 for the clutch, plus $400–$800 labor for installation, as the transmission must be removed.

Cooling System Upgrades

High boost produces massive heat. An upgraded radiator (e.g., Koyo, Mishimoto) is recommended. Oil coolers and transmission coolers prevent thermal failure. These parts add $500–$1,200, but they are critical for reliability in a daily-driven WRX.

Engine Internals (for high horsepower)

If you plan to exceed 450 whp, the FA20’s connecting rods and pistons may become weak points. Building the short block with forged rods and pistons (Manley, Carrillo) costs $3,000–$5,000 in parts alone, plus labor for engine removal and reassembly. This can triple the total project cost.

Exhaust System

A turbo upgrade requires a free-flowing exhaust to prevent backpressure. A catless downpipe and a 3” exhaust system are typical. Prices range from $400–$1,200. Additionally, altering the exhaust routing may be needed to clear the larger turbo.

Installation Options: DIY vs. Professional

Many Subaru enthusiasts choose to install a turbo kit themselves to save labor costs, but this is not for the faint of heart. The FA20 engine bay is tight, and the turbo is low on the driver’s side. Tasks include:

  • Disconnecting factory turbo lines and manifold
  • Modifying or removing the intake manifold for access
  • Fabricating intercooler piping (if not a direct-bolt kit)
  • Relocating components like the airbox, windshield washer reservoir, or ABS pump
  • Properly clocking the turbo, adjusting wastegate spring, and setting base boost

DIY installation can take 40–80 hours for a first-timer, plus the risk of creating a leak or damaging sensors. Professional installation by a Subaru specialist like AMS Motorsports or a regional tuner guarantees the work is done correctly and often includes a small warranty on labor. The trade-off is cost: typically $1,500–$5,000, but it can save headaches and potential engine damage.

Recommendation: If you have mechanical experience and a WRX service manual, DIY is viable for a bolt-on kit. For custom builds or high-horsepower goals, hire a professional.

Performance Gains and What to Expect

After installation and tuning, an upgraded turbo kit transforms the FA20 WRX. Realistic results for a well-chosen stage 1+ kit (like a Garrett GTX3071R on pump gas) include:

  • Peak horsepower: 380–420 whp
  • Peak torque: 380–420 lb-ft
  • Boost pressure: 22–25 psi
  • 0–60 mph: 3.8–4.2 seconds (with sticky tires)
  • ¼-mile: 11.5–12.0 seconds at 118–125 mph

Larger turbos (e.g., Precision 6266) on E85 fuel can reach 500–550 whp, but spool is later (4,000+ RPM). The trade-off between quick spool and peak power is a key consideration when choosing a kit. It is recommended to read owner reviews on NASIOC or the WRX subreddit to understand real-world driveability.

Long-Term Considerations and Reliability

Upgrading the turbo on an FA21 (note: original text says FA20 but FA20 is correct) WRX significantly increases stress on the engine and drivetrain. Key longevity factors:

  • Oil starvation: Some aftermarket turbochargers require better oil supply; an oil cooler and restrictor are essential.
  • Heat management: High EGTs (exhaust gas temperatures) can damage valves and pistons. Proper tuning and sufficient intercooling are critical.
  • Early wear items: The turbo itself may need a rebuild after 60,000–80,000 miles; the clutch will wear faster; and the transmission may fail if driven aggressively.
  • Warranty voiding: Installing a turbo kit voids the factory powertrain warranty. Aftermarket coverage (e.g., from companies like Endurance) may not cover modified cars.

Regular maintenance intervals shorten: expect oil changes every 3,000 miles, spark plug replacement more frequently, and monitoring of boost leaks and exhaust leaks. A well-built, conservatively tuned turbo kit can last 100,000+ miles with proper care, but a half-baked build is prone to failures.

Frequently Asked Questions

Q: Can I install a turbo kit on a stock FA20 WRX without any other modifications?
A: At minimum, you need a tune. For modest gains (350 whp), stock fuel system and clutch may hold, but it is not recommended. Supporting modifications improve reliability.

Q: What is the cheapest turbo kit for the FA20 WRX?
A: A basic Stage 1+ kit from eBay or Chinese wholesalers can be found for $1,200–$2,000, but quality and fitment are often poor. Many end up spending more on fabrication and replacement parts later.

Q: How much horsepower can the FA20 block handle?
A: On stock internals, 450–500 whp is considered the limit on a safe tune. Beyond that, forged rods and pistons are necessary.

Q: Should I buy a used turbo kit?
A: Yes, if you can verify the condition of the turbine wheel, bearings, and seals. Inspect for shaft play. Used kits from reputable brands can save 30–40%. Pre-purchase inspection is essential.

Q: Do I need a new downpipe?
A: Most aftermarket turbo kits require a specific downpipe (often 3” or 4”) to match the turbo outlet. Some kits include one.

Conclusion

Installing a turbo kit on your FA20 Subaru WRX is an exciting path to dramatically increased performance, but the costs add up far beyond the initial turbo kit price. Between the turbo itself, manifold, wastegate, intercooler, piping, fuel system upgrades, clutch, tuning, and labor, a reliable 400+ whp build typically runs $6,000–$12,000 in total. Cuts in quality or skipping supporting modifications can lead to poor driveability or engine failure, ultimately costing more. By researching thoroughly, budgeting for every component, and working with a reputable tuner and installer, you can enjoy a transformed WRX that performs reliably for years.

For further reading, check out COBB’s WRX modding guide or join the FA20 WRX owners’ group for firsthand experiences.