The Subaru FA20 engine has carved out a unique niche among performance enthusiasts, thanks to its low center of gravity, free-revving nature, and the lightweight chassis it typically powers. Found in the Subaru BRZ and Toyota 86, this 2.0-liter flat-four offers a balance of handling and efficiency that makes it a favorite for both daily driving and track work. However, the factory output—around 200 horsepower—often leaves owners wanting more. Enter the aftermarket turbocharged build, which can transform the FA20 into a serious powerplant capable of over 300 horsepower. This expanded comparison dives deep into the trade-offs in power, cost, and reliability between stock and turbocharged FA20 builds, helping you decide which path aligns with your goals.

Overview of the FA20 Engine

The FA20 is part of Subaru's "FA" series of boxer engines, introduced in 2012. It features a 2.0-liter displacement, dual overhead camshafts, and both direct and port fuel injection (depending on the variant). The naturally aspirated version in the BRZ/86 produces about 200 horsepower and 151 lb-ft of torque, with a redline of 7,400 rpm. The engine’s horizontally opposed layout keeps the center of gravity low, which is a major factor in the car’s renowned handling balance.

Subaru also produced a turbocharged version of the FA20, the FA20DIT, which appears in the WRX and some Legacy models, but that’s a different platform. This article focuses on the naturally aspirated FA20 as found in the BRZ/86 and the challenges and rewards of adding a forced induction system aftermarket.

For more technical details on the FA20’s architecture, you can refer to Subaru’s official engine information page at Subaru FA20 Engine.

Stock FA20 Performance

The stock FA20 is not a powerhouse by modern standards, but it offers a pure, engaging driving experience. Its power delivery is linear, with a noticeable surge above 5,000 rpm. The car’s lightweight (around 2,800 pounds) and precise chassis mean the 200 horsepower feels more lively than the numbers suggest. The 0–60 mph time of about 6.5 seconds is modest, but the real joy comes from keeping the engine on boil through corners.

  • Horsepower: 200 hp at 7,000 rpm
  • Torque: 151 lb-ft at 6,400 rpm
  • 0–60 mph: 6.2–6.6 seconds
  • Fuel Economy: 22 city / 30 highway (manual)
  • Aftermarket Potential: Minimal gains from bolt-ons (intake, exhaust, tune yield ~210–220 whp)

The stock configuration is reliable when properly maintained. Common issues include the valve spring recall on earlier models (check if yours is affected) and occasional oil consumption. However, with regular oil changes and routine care, the engine can easily exceed 100,000 miles without major work. The stock car also benefits from low running costs, including affordable insurance and tires.

Areas Where Stock Falls Short

For enthusiasts seeking more punch, the FA20’s torque curve is the main complaint. There’s a dip in the mid-range around 3,500–4,500 rpm, often called the "torque dip," which makes day-to-day driving feel slightly sluggish. A header-back exhaust and a tune can largely fix this, but true high-end power remains limited by the naturally aspirated design.

Aftermarket Turbocharged Builds

Adding a turbocharger to the FA20 transforms the car’s character entirely. With a well-designed kit, horsepower can jump to 300–400 whp, and torque can exceed 350 lb-ft. The acceleration becomes brutal—0–60 mph times can drop to 4.5 seconds or less, putting the car in Corvette territory.

However, the path to big power is not a simple bolt-on affair. It requires careful selection of components, supporting mods, and professional tuning. Let’s look at typical staged builds:

Stage 1: Mild Turbo (Low Boost)

  • Parts: Small-frame turbo (e.g., Garrett GT2860RS or BorgWarner EFR 6258), intercooler, oil/coolant lines, wastegate, blow-off valve, MAP sensor, and a tune.
  • Horsepower: 280–320 whp on pump gas (93 octane)
  • Supporting Mods: Upgraded clutch, larger fuel injectors (550cc), and a fuel pump. No internal engine work required at this level.
  • Cost: $5,000–$7,000 for kit and installation, depending on labor rates.

Stage 2: Moderate Turbo (Mid Boost)

  • Parts: Larger turbo (e.g., GT3076R), upgraded intercooler, full 3-inch exhaust, port fuel injection or flex fuel sensor for E85.
  • Horsepower: 350–400 whp
  • Supporting Mods: Stronger clutch, oil cooler, catch can, often a built short block (forged pistons and rods) to handle the extra cylinder pressure.
  • Cost: $10,000–$15,000 including built engine.

Stage 3: High-Power Builds

  • Parts: Big turbo (e.g., GT3582R), water/methanol injection, standalone ECU, fully built engine, stronger transmission and differential.
  • Horsepower: 450+ whp
  • Cost: $20,000+ with full drivetrain upgrades.

For a real-world example, check out this detailed build on the FT86 Club Forced Induction forum, where owners share their experiences and dyno sheets.

Cost Comparison

The financial difference between staying stock and going turbocharged is vast. Below is a detailed breakdown of ownership costs for both options.

Stock FA20 Costs

  • Purchase Price (used, 2013–2020): $15,000–$25,000 depending on miles and condition
  • Annual Maintenance: $500–$1,000 (oil changes, filters, brake pads, tires)
  • Insurance: ~$1,200–$1,800 per year for a 30-year-old with clean record
  • Fuel (15,000 miles/year): ~$1,500 (premium gas)
  • Long-term Reliability: No major engine expenses for 100k+ miles

Aftermarket Turbo Costs

  • Turbo Kit (including supporting parts): $4,000–$10,000 for a complete quality kit (e.g., from Perrin Performance)
  • Installation (labor): $1,500–$3,000 at a reputable shop
  • Tuning (dyno or remote): $500–$1,500
  • Supporting Mods (clutch, fuel system, cooling): $1,500–$5,000
  • Potential Engine Build (if pushing over 350 whp): $5,000–$12,000 for forged pistons, rods, bearings, and labor
  • Increased Maintenance: More frequent oil changes (every 3,000–5,000 miles), spark plugs, higher tire wear due to torque, and potential for broken parts.
  • Insurance Increase: Many insurers will hike rates or drop coverage if they discover forced induction modifications. Some specialist insurers (like Hagerty) offer policies but at a premium.

In total, a reliable stage 1 turbo build can cost $8,000–$12,000 on top of the car purchase. A stage 2 build with a reinforced engine can easily run $15,000–$25,000. For many enthusiasts, that might exceed the car’s value, but the resulting performance is transformative.

Reliability Factors

Reliability is the make-or-break factor. The stock FA20 is known to be durable when left alone, but adding boost introduces new stress points. Let’s compare each scenario.

Stock FA20 Reliability

  • Proven Dependability: The engine has been in production for over a decade with few systemic failures outside the early valve spring recall.
  • Oil Consumption: Some FA20s consume oil at higher mileage, but this is manageable with regular checks.
  • Maintenance: Simple and inexpensive. Timing chain, no major carbon buildup on direct-injection models (though intake valve cleaning is recommended every 60k miles).
  • Daily Drivability: Excellent. No heat soak issues in traffic, reliable cold starts, and minimal drivetrain strain.

Aftermarket Turbo Reliability

  • Increased Wear: Boost pressures of 8–15 psi roughly double the cylinder pressure, stressing rods, pistons, and bearings. Even with stock internals, a conservative tune on low boost (under 300 whp) can last many miles, but pushing higher without forged components risks catastrophic failure.
  • Heat Management: Turbos generate significant heat. Oil cooling, intercooling, and possibly an oil cooler are mandatory. Heat soak can reduce power on track days.
  • Tuning Quality: An improper tune (too rich, too lean, too much timing) can quickly destroy the engine. Always use a tuner with proven FA20 experience.
  • Maintenance Schedule: Oil changes at 3,000–4,000 miles with high-zinc synthetic oil. Frequent checks of boost leaks, wastegate operation, and fuel trims.
  • Common Failure Points: Weak stock connecting rods are the first to go over 350 whp. Also, the stock fuel system runs out of capacity around 330–350 whp. Clutch failure is common if a stronger unit isn’t installed.

A well-executed turbo build with forged internals and a conservative tune can be reliable for many thousands of miles. However, the margin for error is slim. For a detailed analysis of FA20 failure modes, the EngineLabs article on FA20 builds provides excellent technical depth.

Making the Choice: Which Path Suits You?

The decision ultimately hinges on your budget, mechanical skill, and driving goals.

Choose Stock or Minor Mods If:

  • You value low running costs, daily comfort, and long-term reliability above all.
  • You enjoy the car’s balance and want to improve it through suspension and tire upgrades rather than power.
  • Your commute is stop-and-go and you don’t want heat management headaches.
  • You’re on a tight budget and can’t afford a $2,000 emergency engine rebuild.

Choose Turbocharged Build If:

  • You crave straight-line speed and the thrill of forced induction.
  • You have at least $10,000 to spend on the build and are prepared for ongoing maintenance costs.
  • You have a second car or alternative transport in case of downtime.
  • You have access to a competent tuner and are willing to learn about engine management, datalogging, and boost control.
  • You’re building for track days or time attack, where the extra power is used in short bursts with proper cooling.

For many, a sweet spot exists: a stock FA20 with a good header, tune, and lightweight flywheel can be immensely rewarding without the complexity of forced induction. If you absolutely need more, start with a low-boost turbo kit from a reputable manufacturer like Crawford Performance or Jotech, which have proven reliability records.

Conclusion

The FA20 is a fantastic platform that rewards its owners regardless of their path. The stock car offers purity, reliability, and affordable fun, while a turbocharged build unlocks tremendous potential for those willing to invest time, money, and attention. Neither choice is wrong—they simply cater to different priorities. By carefully evaluating the cost, power gains, and reliability trade-offs outlined in this comparison, you can make an informed decision that will bring you years of driving enjoyment. Remember to factor in not just the initial build cost, but the long-term commitment required to keep a boosted FA20 happy.