The GReddy Supercharger is a popular performance upgrade for the Subaru BRZ FA20 engine. This article will explore the costs associated with installing this supercharger and the potential power gains you can expect, as well as deeper details on installation, tuning, supporting modifications, and long-term reliability.

Overview of the GReddy Supercharger System

The GReddy Supercharger kit for the Subaru BRZ (and Scion FR-S/Toyota 86) uses a centrifugal design, which is belt-driven and provides linear boost that increases with engine RPM. Unlike positive-displacement superchargers (like Eaton roots-style units), centrifugal units behave similarly to a turbocharger but without exhaust lag. The kit from GReddy typically includes a cast aluminum intake manifold, a billet compressor housing, a high-flow air filter, an intercooler (air-to-air), blow-off valve, all necessary brackets and belts, and detailed instructions.

The FA20 engine is a 2.0-liter boxer four-cylinder that responds very well to forced induction. The GReddy system is engineered to bolt on without needing to remove the engine or modify the chassis, making it an attractive choice for DIY installers. The kit is CARB exempt (EO number D-670-14) for 2013–2020 models, meaning it's street legal in California and other states that follow CARB regulations.

Detailed Cost Breakdown

While the base article gave rough ranges, let's break down the costs more granularly. Prices may vary by vendor and region.

  • Base supercharger kit: $4,400–$5,200 (includes intercooler, intake piping, brackets, belt, blow-off valve, and ECU reflash option).
  • Optional high-flow fuel injectors: $500–$700 for a set of four (e.g., DeatschWerks 700cc or Injector Dynamics 1050x).
  • Upgraded fuel pump: $150–$250 (e.g., AEM 340lph or DW300).
  • Oil cooler: $400–$800 (recommended for track use).
  • Custom dyno tune: $400–$800 (if not using the included base map).
  • Labor if not DIY: $800–$1,200 (typically 8–14 hours at a performance shop).
  • Miscellaneous (gaskets, fluids, upgraded spark plugs, catch can): $200–$400.

All-in, you should budget $7,000 to $9,000 for a properly installed and tuned GReddy supercharger on an FA20 BRZ. This accounts for both the kit and the necessary supporting modifications to ensure reliability and maximum performance.

Power Gains and Expected Performance

The GReddy supercharger at its base boost level (approximately 6–8 psi on the standard pulley) typically delivers 260–290 wheel horsepower and 210–230 lb-ft of torque. That's about a 70–100 hp increase over the stock 205 hp (crank) rating. With E85 fuel and a tune, owners have seen over 330 whp.

Here are typical gains by fuel type and pulley:

  • Pump 91 octane (stock pulley): +80–90 hp, +60–70 lb-ft torque.
  • Pump 93 octane (stock pulley): +90–100 hp, +65–75 lb-ft.
  • E85 (stock pulley): +110–120 hp, +80–90 lb-ft.
  • Upgraded pulley (9–10 psi) on 93 octane: +110–125 hp, +85–95 lb-ft.

These numbers are at the wheels, so crank horsepower is roughly 15% higher. The power delivery is smooth and very drivable, with the supercharger making noticeable boost from 3,500 RPM onward and pulling hard to the 7,400 RPM redline. Because the FA20 engine has a high compression ratio (12.5:1), careful tuning is essential to prevent knock.

Supporting Modifications for Optimal Results

Simply bolting on the supercharger without supporting mods will work for low boost, but to maximize gains and reliability, consider these upgrades:

Fuel System

The stock fuel injectors and pump are borderline for 260+ whp. Upgrading to at least 700cc injectors and a high-flow fuel pump is strongly recommended. Some kits from GReddy now include a fuel pump booster, but many owners prefer a full replacement pump for consistency.

Cooling

The FA20 is known for high oil temperatures, especially under boosted conditions. An oil cooler is virtually mandatory for any track driving or sustained highway pulls. The GReddy kit includes an intercooler, but upgrading to a larger core or adding a water-methanol injection system can help on hot days.

Exhaust System

While not required, a catless or high-flow front pipe and a less restrictive cat-back exhaust can free up 10–15 hp and reduce exhaust gas temperature. The stock exhaust is quite restrictive on a forced-induction FA20.

Clutch

The stock clutch will hold the extra torque for a while, but eventually it will slip, especially on E85 or with a smaller pulley. A stage 1 or stage 2 clutch (e.g., ACT, Exedy) is a wise investment when the stock clutch gives out.

Installation Process Overview

The GReddy kit is designed for home installation, though it is time-consuming. Expect an intermediate to advanced skill level. The main steps include:

  1. Disconnect battery and drain coolant.
  2. Remove intake manifold and related components.
  3. Install the intercooler and charge piping in the front bumper area.
  4. Mount the supercharger bracket and compressor unit to the engine block using the provided hardware.
  5. Run belt tensioner and install the drive belt.
  6. Install blow-off valve, intake tube, and air filter.
  7. Replace spark plugs (IRidium ones recommended for boosted applications).
  8. Reconnect coolant lines, vacuum hoses, and wiring for the bypass valve.
  9. Load the provided base tune via a laptop using an ECUTek cable (or take to a tuner).
  10. Double-check all bolts and hoses, then start engine and check for leaks.

Total install time for a first-timer is 12–20 hours. Professional shops can do it in 8–12 hours. It is critical to follow the torque specs and to use thread locker on supercharger bracket bolts to prevent loosening.

Tuning Requirements

The GReddy kit optionally comes with an ECUTek reflash license and a base map suitable for stock injectors and 91 octane fuel. However, most owners report that a custom tune yields noticeably more power and smoother drivability. A dyno tune with a local tuner is ideal because they can adjust timing, fuel tables, and knock control in real time. Alternatively, e-tuning services (sending datalogs to a remote tuner) are cost-effective and work well for street-driven cars.

Key tuning parameters: lambda targets of 0.80–0.85 under boost, ignition timing advanced until knock threshold, and throttle mapping adjusted for the extra torque. A well-tuned car will have no surging, flat spots, or knock events.

Reliability and Long-Term Considerations

With proper supporting mods and a conservative tune, a GReddy supercharged FA20 can last 60,000–100,000 miles without major issues. However, the engine is not indestructible; here are common reliability points:

  • Oil change intervals: Reduce to 3,000–4,000 miles with full synthetic 5W-30 or 0W-40. The supercharger places additional heat load on the oil.
  • Fuel quality: Always use top-tier 91+ octane. One tank of low-octane fuel can cause pre-ignition and damage ring lands.
  • PCV system: Boost can cause blow-by and oil buildup in the intake. A catch can or AOS is highly recommended to keep the intercooler and valves clean.
  • Serpentine belt: Inspect every 15,000 miles; the supercharger adds load and can wear belts faster.
  • Cooling system: Upgrade the radiator if you track the car. The stock radiator can handle street driving, but sustained high RPM will push coolant temps up.

Despite these precautions, many owners daily-drive their supercharged BRZ with high reliability. The key is not to exceed 10 psi on pump gas without built internals (forged pistons and rods) and to always monitor oil temperature.

Comparison with Other Supercharger Options

The BRZ FA20 aftermarket has several supercharger kits. Here's how the GReddy compares:

  • Jackson Racing C-30/38: Uses a Rotrex centrifugal unit; similar power levels, but Jackson Racing provides a more comprehensive kit with a heat exchanger and oil cooler. GReddy is often less expensive.
  • Vortech V3: Another centrifugal option that makes slightly more top-end power; however, the kit requires cutting the bumper and is more complex to install.
  • Harrop TVS1320: A positive-displacement supercharger with instant torque; it's more expensive ($6k+) and requires additional cooling modifications. GReddy is simpler and lighter.
  • Edelbrock E-Force: Also positive-displacement; makes strong low-end torque but is heavier and costs more.

The GReddy kit strikes a balance between price, reliability, and ease of installation. It's a great choice for those who want a solid 300 whp without breaking the bank or dealing with complex fabrication.

Real-World Owner Experiences

After scouring enthusiast forums and owners' groups, a few common themes emerge:

  • "Installation took me a weekend, but the instructions were clear. The hardest part was routing the intercooler piping on the passenger side."
  • "I got 277 whp on 91 octane with just the kit and a custom tune. It transforms the car; the power band is linear and the car finally feels quick."
  • "Track day oil temps hit 260°F before I installed an oil cooler. After the cooler, steady 220°F. Do not skip this mod if you drive hard."
  • "My clutch started slipping after 5,000 miles of aggressive driving. I upgraded to an ACT stage 2 and it's been fine ever since."
  • "The CARB exemption was a big reason I chose GReddy; peace of mind in California."

Overall satisfaction is high, with most owners saying the kit delivers as promised. The main complaints are the need for a clutch upgrade and the lack of an included oil cooler for track use.

Conclusion

The GReddy supercharger is an excellent option for BRZ FA20 owners looking to boost their vehicle's performance. While the initial costs can be significant—often $7,000 to $9,000 when done properly—the power gains of 80–120 whp and the enhanced driving experience make it a worthwhile investment for many enthusiasts. Pay careful attention to supporting modifications (fuel, cooling, tune, clutch) and maintenance, and you'll have a reliable, street-legal, and seriously fun sports car.

For more information, check out the GReddy official site for kit details, or visit the FT86Club supercharger section for owner reviews and tuning tips. You can also refer to Delicious Tuning for one of the most popular remote tuning services specifically for the FA20 supercharged platform.