Understanding Supercharger Displacement and the FA20 Engine

The Subaru BRZ's FA20 engine is a 2.0-liter naturally aspirated boxer four-cylinder that produces roughly 200 horsepower from the factory. Its high compression ratio (12.5:1) and relatively lightweight reciprocating assembly make it responsive to forced induction, but also impose limits on how much boost it can safely handle. Supercharger displacement – measured in liters per revolution – is a key factor in determining exactly how much additional air the compressor can push into the engine. A 1.7L supercharger delivers roughly 1.7 liters of air per rotor revolution, while a 2.0L unit pushes 2.0 liters. That difference in swept volume directly influences achievable boost pressure, heat generation, and power output.

Because the FA20 is a small-displacement engine with a redline near 7,400 RPM, choosing the right supercharger size means balancing airflow at high RPM against the risk of overspinning the compressor or creating excessive intake air temperatures. The 1.7L and 2.0L sizes represent two popular sweet spots that match the engine’s airflow curve without requiring extensive internal modifications – at least up to a point.

1.7L Supercharger: Balanced Power for Daily Driving and Occasional Track Use

A 1.7L supercharger is often the first choice for BRZ owners who want a noticeable power increase without transforming the car into a high-strung specialty vehicle. These kits typically produce between 230 and 280 wheel horsepower on pump gas, depending on pulley selection, exhaust setup, and tuning. The power comes on smoothly, with strong mid-range torque that makes the car feel genuinely quicker on public roads.

Why the 1.7L Size Fits the FA20

The FA20’s airflow capacity at 7,000+ RPM is well matched to a 1.7L positive-displacement blower running at a moderate drive ratio. The compressor stays within its efficiency island, producing boost in the 6–9 psi range without excessive heat. This means the stock intercooler (if fitted) or air-to-water system can keep intake temperatures in check, and the engine’s knock-limited timing can remain aggressive. Owners report that a well-tuned 1.7L setup still returns reasonable fuel economy and doesn’t require upgrading the clutch or fuel system in most cases, though an aftermarket fuel pump is a wise safety measure.

  • Jackson Racing Supercharger Kit (C38-71 Rotrex) – This kit uses a centrifugal supercharger (not a twin-screw, despite the “1.7L” terminology often applied to the system’s displacement equivalent). It delivers linear power that builds to a strong top end, with excellent heat management thanks to an included air-to-water intercooler. Typical output is 240–270 whp on 91 octane. The kit is CARB-approved for street use, making it one of the most straightforward upgrades available. Jackson Racing BRZ Supercharger Kit
  • Vortech V3 Si Supercharger System – Another centrifugal design, the V3 Si features self-contained oiling (no need to tap into the engine) and can be tuned for 6–10 psi. Many tuners prefer this kit for its reliability and ease of installation. It also responds well to smaller pulleys if you later want to increase boost, giving some headroom beyond the 1.7L equivalent flow. Vortech V3 Si for BRZ

Performance Expectations with a 1.7L Supercharger

With a proper tune, expect a 0–60 time improvement of roughly 1.0–1.5 seconds, dropping from around 6.4 seconds stock to the low 5s. Quarter-mile times fall from the mid-14s to low 13s. More importantly, the driving experience becomes more engaging: the car pulls hard from 3,500 RPM to redline, and overtaking on the highway no longer requires a downshift and a prayer. The engine retains its character, with no excessive vibrations or unusual noises.

2.0L Supercharger: Pushing the FA20 Toward Its Limits

Moving up to a 2.0L supercharger means targeting 300+ wheel horsepower. This is territory where the stock FA20 internals (pistons, rods, bearings) are considered safe up to about 350 whp, but the real challenge is thermal management, fuel delivery, and clutch capacity. A 2.0L blower spinning at a reasonable drive ratio produces 10–14 psi of boost, and at those pressures the intake air can easily exceed 140°F without adequate intercooling. The engine also becomes knock-limited, requiring premium fuel and often water-methanol injection to keep combustion stable.

When a 2.0L Makes Sense

If your goal is a dedicated track car or a street machine that sees frequent drag strip or autocross events, the 2.0L offers the headroom to make serious power. The larger compressor flows enough air to support up to 400+ whp with supporting mods (built short block, larger injectors, upgraded fuel pump, and a twin-disc clutch). For a daily driver, the compromises in fuel economy (expect a 3–5 MPG drop), increased cabin heat, and added stress on the drivetrain often outweigh the thrill of 100+ extra horsepower.

  • HKS GT2 Supercharger Kit (GT2-4540) – HKS’s offering uses a twin-screw Lysholm-type compressor that provides instant low-RPM boost. The kit includes a huge air-to-air intercooler and a blow-off valve. It typically produces 300–330 whp on 93 octane with a conservative tune. The GT2 is known for its robust build quality and smooth power delivery, though installation is more involved than a centrifugal kit. HKS GT2 Supercharger for BRZ
  • GReddy Turbocharger / Supercharger System – GReddy’s supercharger option (often confused with their turbo kits) uses a centrifugal compressor sourced from Trust/GReddy that flows approximately 2.0L per revolution. It includes a front-mount intercooler and can be configured for low boost (~8 psi) or high boost (~14 psi) via pulley swaps. The kit is less common now but still available through specialty retailers, and it offers a good balance of price and performance. GReddy Supercharger for BRZ

Performance Expectations with a 2.0L Supercharger

A properly tuned 2.0L setup can push the BRZ into low 12-second quarter-mile times, with traps around 115–120 mph. 0–60 times drop into the upper 4-second range. The downside is that the car becomes more demanding: you’ll need to watch oil temperatures (aftermarket oil cooler is mandatory), upgrade to a high-capacity radiator, and consider an aftermarket clutch within the first few thousand miles. The factory clutch will slip at around 280 ft-lbs of torque, and a 2.0L supercharger easily exceeds that.

Reliability Deep Dive: How to Keep Your Supercharged BRZ Alive

Reliability is the single biggest concern when adding forced induction to the FA20 engine. The engine has known weaknesses: a plastic oil pickup tube that can crack, weak connecting rod bolts, and a tendency to detonate if the tune is aggressive or the fuel quality is poor. With either supercharger size, the following upgrades are highly recommended:

Critical Supporting Modifications

  • Oil cooling: An oil cooler with at least 13 rows is essential. The FA20 runs hot even in stock form, and boost adds significant heat. Oil temps above 250°F degrade lubricant and increase wear.
  • Fuel system: Upgrade to a DW300c or AEM 340 lph fuel pump. For 2.0L kits, adding 1300cc injectors and a Flex Fuel sensor for E85 is strongly advised – ethanol provides knock resistance that lets you run more timing and boost safely.
  • Tuning: A custom dyno tune (not an off-the-shelf map) is non-negotiable. Find a tuner experienced with the FA20 and the specific supercharger model. Most recommend conservative lambda targets (0.78–0.80) and aggressive ignition retard under load to protect ring lands.
  • Transmission and clutch: The stock clutch will not hold 1.7L power for long if you drive hard. The 2.0L will glaze it in a few launches. Upgrade to an Exedy Stage 1 (for 1.7L) or a twin-disc setup (for 2.0L).
  • Cooling system: Upgrade the radiator to a Koyorad or CSF unit. For 2.0L kits, consider a water-methanol injection kit to cool intake air and suppress knock.

Maintenance Intervals and Checks

Superchargers themselves require periodic maintenance – most have a service interval of 60,000–80,000 miles for oil changes in the blower unit. Belts should be inspected every 15,000 miles for wear, and pulleys should be checked for wobble. The intercooler core should be cleaned of debris annually, especially if you drive in dusty conditions. Most importantly, log your engine data (AFR, ignition timing, boost pressure, oil temperature) at least once a month to catch any creeping issues before they cause damage.

Comparison: 1.7L vs 2.0L at a Glance

  • Target Power: 1.7L = 230–280 whp; 2.0L = 300–380 whp
  • Boost Level: 1.7L = 6–9 psi; 2.0L = 10–14 psi
  • Fuel Requirement: 91 octane minimum for both, E85 recommended for 2.0L
  • Clutch Needed: Optional for 1.7L (recommended); mandatory for 2.0L
  • Intercooler Type: Air-to-water (most 1.7L kits) vs air-to-air (most 2.0L kits)
  • Drivability: 1.7L retains daily-driver character; 2.0L is more of a weekend warrior
  • Engine Modifications Required: Minimal for 1.7L; often require oil cooler, fuel system, and sometimes a head stud upgrade for 2.0L

Choosing the Right Path for Your Build

The best supercharger size depends entirely on your intended use and budget. If you want a car that feels alive during a canyon run but still starts reliably every morning and gets 25+ MPG on the highway, a 1.7L kit is the logical choice. It enhances the BRZ's strengths without overwhelming its weaknesses. On the other hand, if you're chasing lap times or building a showpiece that makes serious power, the 2.0L delivers the kind of neck-snapping torque that turns the BRZ into a genuine performance machine.

Whichever size you choose, invest in a quality tune from a reputable shop, don’t skimp on supporting modifications, and keep up with maintenance. The FA20 is a capable engine when treated with respect, and either supercharger size can provide years of reliable enjoyment.