The Subaru BRZ is celebrated by driving purists for its balanced chassis, razor-sharp steering, and lightweight construction. Yet, even the most enthusiastic BRZ owners often feel the car’s 2.0-liter naturally aspirated engine leaves untapped potential on the table. For those seeking a transformative increase in power without compromising the car’s inherent driving dynamics, the AEM 300 HP Turbo System stands out as a purpose-built solution. This system is engineered specifically for the FA20 engine found in the BRZ and its twin, the Scion FR-S / Toyota 86, delivering a reliable and substantial jump to the 300-horsepower mark. This guide explores every facet of this turbo system, from its core components and installation to tuning, supporting modifications, and long-term ownership considerations, so you can maximize your BRZ’s performance with confidence.

Understanding the AEM 300 HP Turbo System

Unlike generic universal turbo kits that require extensive fabrication and guesswork, the AEM 300 HP Turbo System is a complete, vehicle-specific kit designed to integrate seamlessly with the Subaru BRZ’s engine bay. It targets a proven power level—300 horsepower at the wheels with proper tuning—while maintaining the daily-drivability and reliability that BRZ owners expect. The system includes every component needed to add forced induction, from the turbocharger itself to the intercooler, exhaust manifold, downpipe, intake piping, and even the necessary hardware for a clean installation.

The heart of the kit is a precision-engineered turbocharger that balances spool characteristics with peak flow. AEM has selected a unit that provides quick boost response—important for a car that thrives on rev-matching and corner exits—while avoiding the lag associated with larger turbos. The result is a powerband that feels factory-installed: linear, progressive, and addictive.

Key components include:

  • Turbocharger: A journal-bearing or ball-bearing unit (depending on the kit version) designed for rapid spool and durability.
  • Cast stainless steel exhaust manifold: Tuned for equal-length runners to improve flow and reduce exhaust pulse interference.
  • Air-to-air intercooler: Low-pressure drop core with cast end tanks to reduce intake temperatures and increase air density.
  • Mandrel-bent charge piping: Smooth internal surfaces minimize turbulence and pressure loss.
  • Downpipe with integrated catalytic converter: Properly sized to maintain exhaust velocity while meeting emissions requirements.
  • Blow-off valve: Bypass valve to protect the turbo compressor and reduce compressor surge.
  • All required gaskets, clamps, and hardware: No need to source extra parts.

AEM also typically includes a pre-configured ECU calibration or the necessary hardware to flash the factory ECU via the ECUTek or similar platform. This is critical: without proper fuel and ignition maps, the extra boost could cause engine damage. AEM’s calibration serves as a safe starting point, but individual dyno tuning is strongly recommended.

Key Features and Engineering Highlights

The AEM system’s design philosophy focuses on three pillars: power, reliability, and fitment. Let’s examine the standout features that make this kit a top choice for BRZ owners looking to reach the 300 HP threshold.

Turbocharger Selection and Spool Characteristics

The turbocharger in the AEM kit is carefully chosen to match the FA20’s displacement (2.0 liters) and intended power target. It typically features a twin-scroll or divided inlet housing (depending on the revision) to improve exhaust pulse separation and reduce turbo lag. At a modest 10-12 psi of boost, the system can deliver strong mid-range torque while still allowing the engine to rev freely to the redline. Many owners report noticeable boost as early as 2,800 RPM, with full spool by 3,500–4,000 RPM—well within the range used during aggressive street driving or track work.

Intercooler Efficiency and Heat Management

Forced induction systems generate significant heat, which can reduce power and increase the risk of detonation. The AEM kit includes a bar-and-plate intercooler core that offers superior heat rejection compared to cheap tube-and-fin designs. The intercooler is sized to fit behind the BRZ’s front bumper without requiring major bumper beam modifications, preserving the car’s structural integrity. Cast end tanks improve flow distribution, ensuring uniform cooling across the core. Under sustained load (e.g., track sessions), the intercooler keeps intake air temperatures within safe limits, allowing the ECU to maintain timing and avoid pulling ignition.

Exhaust Manifold Design

The custom exhaust manifold is a standout feature. AEM engineers used computational fluid dynamics (CFD) to design equal-length primary tubes that merge smoothly into the collector. This design reduces exhaust backpressure and promotes efficient scavenging, which helps the turbo spool quickly while also improving throttle response. The manifold is made from stainless steel with a high-temperature coating (optional) to reduce under-hood heat and protect surrounding components.

ECU Integration and Tuning Flexibility

Modern turbocharging relies heavily on engine management. The AEM system includes an ECUTek ProECU license and a base calibration designed to get the car running safely. ECUTek is a widely respected tuning platform for Subaru vehicles, offering features like flex-fuel support, boost control maps, launch control, flat-foot shifting, and advanced datalogging. The base map is conservative, targeting around 280–300 wheel horsepower on 91 octane fuel, but it can be refined by a professional tuner for greater output or for use with ethanol blends like E85.

For those who prefer a standalone ECU, the kit can also be adapted to work with systems like the Haltech Elite 2500 or Motec M1, though that adds cost and complexity. Most owners stick with the ECUTek flash because it retains all factory features (cruise control, AC, emissions readiness) and is plug-and-play.

Installation Process: What to Expect

Installing a turbo system on a naturally aspirated engine is a major project. The AEM 300 HP Turbo System is considered a mid-level to advanced installation, requiring mechanical skill, specialized tools, and about 15–25 hours of labor for a first-time builder. However, because the kit is vehicle-specific, there is no need for welding, cutting, or custom fabrication—everything bolts on using factory mounting points.

Step-by-Step Overview

  1. Prep and Disassembly: Disconnect the battery, drain the coolant and oil, remove the factory intake manifold, exhaust headers, and air intake system. The front bumper must be removed to access the intercooler area.
  2. Install the Exhaust Manifold and Turbo: Bolt the AEM manifold to the cylinder head using new gaskets. Mount the turbocharger to the manifold and connect the oil feed and drain lines. AEM includes a oil scavenge pump (for turbochargers mounted low) or a gravity drain setup.
  3. Intercooler and Piping: Mount the intercooler behind the front bumper using the provided brackets. Route the charge pipes from the turbo compressor outlet through the intercooler and into the throttle body. Secure all connections with heavy-duty silicone couplers and T-bolt clamps.
  4. Downpipe and Exhaust: Install the downpipe that connects the turbo outlet to the factory exhaust (or an aftermarket cat-back system). The kit’s downpipe includes a high-flow catalytic converter to minimize smell and noise while keeping emissions legal.
  5. Intake System: Replace the factory air box with the AEM filter and intake tube. The filter is usually mounted in the fender well for cold air access.
  6. Wastegate and Blow-Off Valve: Connect the external wastegate (if equipped) and blow-off valve. Adjust the boost controller (included or part of the ECU) to achieve desired boost levels.
  7. ECU Flashing: Connect the ECUTek cable to the OBD-II port. Flash the base calibration provided by AEM. Ensure no check engine lights appear.
  8. Final Checks and Testing: Refill fluids, check for leaks (using a smoke tester or soapy water), and inspect all connections. Start the engine, allow it to idle, and check for proper operation. A test drive with careful monitoring of AFRs and boost is essential before pushing the car.

Important: Even with the base calibration, a professional dyno tune is recommended to optimize timing, fuel, and boost for your specific fuel quality and climate. Many reputable shops specialize in FA20 turbo tuning, such as Delicious Tuning or Crawford Performance.

Performance Gains: Real-World Results

The AEM 300 HP Turbo System delivers a transformative driving experience. While the BRZ’s stock engine produces around 200–205 horsepower at the crank (about 170–175 whp), this kit elevates output to 300–320 wheel horsepower on a conservative tune. That’s an increase of roughly 75–80% at the wheels.

Dyno Numbers

Typical results on a Mustang or Dynojet (SAE corrected) show:

  • Peak Power: 295–315 whp at 6,800–7,200 RPM
  • Peak Torque: 260–290 lb-ft at 3,800–4,500 RPM
  • Boost: 10–12 psi tapering to 8–10 psi at redline

On E85 fuel with a custom tune, outputs of 330–350 whp are achievable while maintaining safe air-fuel ratios and knock margin.

Drivability Improvements

Beyond the peak numbers, the turbo system massively improves the BRZ’s daily driving experience. The torque curve fills the gap below 4,000 RPM, where the stock engine felt lethargic. Overtaking on highways, climbing steep grades, and launching from a stop all feel effortless. The car retains its high-revving character—the turbo doesn’t sign off early—so it still rewards spirited driving to the redline.

Supporting Modifications for Maximum Reliability

Adding 300 horsepower to a car originally designed for 200 puts stress on various systems. To ensure long-term reliability and optimal performance, consider these supporting upgrades:

Fuel System Upgrades

The stock injectors and fuel pump may struggle to supply enough volume at higher boost levels, especially with E85. AEM recommends upgrading to high-flow fuel injectors (e.g., 700cc–1000cc) and a 255 LPH or 340 LPH fuel pump. The kit may include these, but verify before purchase. A fuel pressure regulator can also help maintain a stable rail pressure.

Cooling System Enhancements

For track use or extended high-load driving, an upgraded radiator (e.g., Koyo or Mishimoto) and an oil cooler are wise investments. The FA20 is known for high oil temperatures under hard driving, and oil temps above 270°F can reduce viscosity and accelerate wear. A thermostatic oil cooler sandwich plate is a common addition.

Clutch and Drivetrain

The stock BRZ clutch can handle about 250–280 whp before slipping. At 300+ whp, a stage 1 or stage 2 clutch kit (e.g., ACT or Exedy) is strongly recommended. The lightweight flywheel that comes with some kits also helps the engine rev quicker. Additionally, the factory differential and axles generally hold up to 300 whp, but if you plan to launch aggressively or run sticky tires, upgrading to stronger axles may be prudent.

Brake and Suspension Changes

With more speed comes more stopping force. Upgraded brake pads (e.g., Carbotech XP10/XP8) and high-temperature brake fluid are minimums. A master cylinder brace and stainless steel lines reduce pedal feel loss. For suspension, stiffer springs and dampers help control the extra weight and higher cornering speeds, but the BRZ’s platform remains balanced.

Tuning and ECU Calibration: Getting the Most Out of the Kit

Proper tuning is the single most important factor in achieving both power and reliability with the AEM kit. The base calibration provided by AEM is a safe, universal map, but it may not be optimized for your specific fuel, altitude, or driving conditions.

Choosing a Tuner

Look for a shop with experience tuning FA20 engines and ECUTek software. Remote tuning is also possible with datalogging and email-based map revisions. Some well-known names in the Subaru BRZ turbo tuning community include:

Common Tuning Considerations

  • Air-Fuel Ratio (AFR): Target 11.5:1 – 12.0:1 under boost for safety on pump gas. Leaner ratios risk detonation; richer ones waste power and fuel.
  • Ignition Timing: Conservative timing is safe; aggressive timing requires excellent fuel and cooling. Many tuners use a “boost vs. ignition” map with a safety buffer.
  • Boost Control: Electronic boost controllers (e.g., Mac valve) allow precise boost ramping. AEM’s base map often targets 10 psi, but a tune can safely run 12–13 psi on 93 octane.
  • Flex Fuel: If you have access to E85, a flex fuel sensor enables the ECU to adjust timing and fueling automatically based on ethanol content. This can unlock 330+ whp with room to spare.

Reliability and Longevity: What to Expect

When properly installed and tuned, the AEM 300 HP Turbo System is known for being reliable and durable. Many owners have logged tens of thousands of miles without major issues. However, longevity depends on proper maintenance and respecting the limits of the FA20 engine.

Engine Preparation

The FA20 has a few weak points that should be addressed before adding boost:

  • Direct injection carbon buildup: Since the FA20 uses direct injection, intake valves tend to accumulate carbon deposits over time. A catch can (e.g., Radium Engineering) helps reduce oil vapor entering the intake tract, but periodic media blasting of the valves may still be needed.
  • Oil starvation issues: Under high lateral g-forces, the FA20 can experience oil pickup starvation. An oil pan baffle and possibly a larger oil cooler can mitigate this.
  • Timing chain and tensioners: Stock components generally hold up to 300 whp, but using a high-quality synthetic oil (5W-30 or 0W-40) with frequent changes (every 3,000–4,000 miles) is critical.

Daily Driving and Track Use

On the street, the kit delivers excellent daily drivability with smooth power delivery and no drivability annoyances. On track, the system holds up well, but cooling upgrades and a high-temperature oil become necessary if you push the car for 20-minute sessions. Many track-oriented BRZ owners pair the AEM kit with a radiator duct kit and hood vents to extract hot air from the engine bay.

Comparing the AEM 300 HP System to Other Turbo Kits

The BRZ/86 aftermarket is rich with turbo options. How does the AEM system stack up?

  • VS. AVO Turbo Kit: AVO offers a similar stage 1 kit targeting 300 HP, but it uses a smaller turbo (TD04) that falls off earlier. AEM’s turbo is often a bit larger and supports higher peak power.
  • VS. Jackson Racing Supercharger: Centrifugal superchargers like Jackson Racing offer instant linear power but lack the high-end punch of a turbo. The AEM turbo produces more torque at lower RPMs.
  • VS. Full-Race or PTuning Turbo Kits: These are high-end custom kits with ball-bearing turbos and top-mount intercoolers. They can make 400+ whp, but cost much more and require more fabrication. The AEM kit is a more accessible entry point to 300 HP.
  • VS. Tuning vs. Self-Sourced Turbo Kits: Some owners piece together their own turbo setup using used parts. While cheaper, that path often leads to fitment issues and longer downtime. The AEM kit saves hours of frustration and includes a known calibration.

For the vast majority of BRZ enthusiasts seeking a proven, reliable 300 HP solution, the AEM system represents the best balance of performance, quality, and value.

Cost Considerations and Budget Planning

Purchasing the AEM 300 HP Turbo System itself costs between $4,500 and $5,500 depending on the retailer and whether it includes upgraded injectors and pump. Installation labor at a competent shop can add $1,500–$2,500. Professional tuning costs an additional $500–$1,000. Supporting modifications (clutch, cooling, fuel system) can add another $1,500–$3,000.

Total investment to get the car running reliably at 300 whp is often $7,500–$10,000. That might seem high, but it’s comparable to buying a turbo from a factory (e.g., a used BMW 335i) and comes with the knowledge that the components are matched. Resale value of a well-modded BRZ can also remain strong if the parts are kept clean and the car is not abused.

Conclusion

The AEM 300 HP Turbo System is a carefully engineered solution that transforms the Subaru BRZ from a fun, momentum car into a serious performance machine. By targeting a power level that respects the engine’s structural limits and leveraging high-quality components, AEM has created a kit that delivers exhilarating acceleration, improved daily drivability, and long-term reliability when installed and tuned correctly. For owners ready to move beyond bolt-on intake and exhaust mods, this turbo system offers a clear path to 300 horsepower without the headaches of a custom fabrication project.

Whether you plan to carve canyon roads, attack track days, or simply enjoy a quicker commute, the AEM system brings out the true potential of the FA20 engine. Pair it with proper supporting mods, invest in a professional dyno tune, and you’ll have a BRZ that not only handles like a dream but also accelerates like a sports car should. The journey to 300 HP is exciting, and AEM makes the destination well within reach.