The Subaru WRX has long been a favorite among driving enthusiasts, offering a turbocharged boxer engine that responds exceptionally well to modification. If you own a 2015+ WRX (or even older models) and are looking to break past the factory 270-horsepower ceiling, upgrading the turbocharger is one of the most effective paths to a 350+ horsepower build. In 2023, several turbo upgrades stand out for their ability to deliver reliable, streetable power while maintaining the WRX's characteristic responsiveness. Below we explore five top-tier turbocharger options, along with the supporting modifications and tuning considerations you'll need to maximize your investment.

1. Garrett GTX2860R Turbocharger

Garrett’s GTX2860R is a staple in the Subaru aftermarket world, and for good reason. This turbocharger uses Garrett’s dual-ball bearing system and a lightweight, low-inertia turbine wheel to achieve rapid spool that feels almost stock. The advanced aerodynamics of the GTX2860R allow it to flow enough air to support up to 350 wheel horsepower while retaining quick throttle response on the factory 2.0L and 2.5L engines.

Key specifications include a 50mm inducer compressor wheel and a 54mm turbine wheel with a 0.64 A/R housing. The compact design makes it a direct bolt-on for many WRX generations, requiring minimal modification to the intercooler piping or oil lines. Spool time is typically in the 3000–3500 rpm range, which means you get strong boost pressure early in the rev range for daily driving fun.

Expect to pair this turbo with a quality downpipe (catted or catless), a high-flow intake, and a thorough tune via an Accessport or other engine management system. Fuel system upgrades are generally not required at this power level, though a high-pressure fuel pump provides extra safety. The GTX2860R is ideal for the enthusiast who wants a responsive, easy-to-live-with upgrade that keeps the WRX reliable on pump gas.

2. Blouch 20G Turbocharger

Blouch Performance has built a strong reputation in the Subaru community for producing robust, high-flow turbochargers. The Blouch 20G is based on the Mitsubishi TD06H-20G compressor wheel but optimized for Subaru applications. It delivers a power band that feels linear and strong, with output ranging from 320 to 360 horsepower depending on the engine configuration and supporting mods.

The 20G uses a large 20G compressor wheel coupled with a high-torque turbine housing to produce excellent mid-range and top-end power. Spool is slightly later than the GTX2860R (typically around 3500–4000 rpm), but the payoff is stronger top-end pull. The Blouch 20G is available in both standard and billet wheel configurations; the billet version offers slightly faster spool and greater efficiency.

This turbocharger works especially well on the WRX when combined with an upgraded intercooler (Garrett core or similar), a full 3-inch turbo-back exhaust, and a capable fuel system with larger injectors or a fuel pump. The 20G is a favorite for road racing and autocross due to its predictable power delivery. Be prepared to invest in a solid tune—protuning or an e-tune from a Subaru specialist is highly recommended to avoid detonation and ensure safe air/fuel ratios.

3. IHI VF48 Turbocharger

The IHI VF48 is a factory option found on the JDM Subaru WRX STI (V11 and V12), making it a popular "OEM+" upgrade for USDM WRX owners. It offers a direct bolt-on fitment with no modification to the exhaust manifold or oil lines. The VF48 features a twin-scroll turbine housing (on newer versions) that helps reduce lag, giving the car a responsive feel similar to the VF52 but with better top-end flow.

With a compressor inducer of approximately 49mm and a turbine wheel designed for quick spool, the VF48 can support 300–350 wheel horsepower when paired with proper mods. The twin-scroll design is particularly beneficial on the 2.0L FA20 and 2.5L EJ engines, improving exhaust pulse separation for a broader power curve.

Installation is straightforward—the VF48 bolts directly to the factory up-pipe and downpipe, though using a larger downpipe will help reduce backpressure. A tune is mandatory, and many owners report noticeable gains in mid-range torque over the stock unit. Because it is a used factory turbo, sourcing a VF48 in good condition is key. Check for shaft play and ensure the wastegate actuates smoothly. This upgrade is best for budget-conscious enthusiasts who want a reliable step up without custom fabrication.

4. Tomei M8250 Turbocharger

Tomei is a name synonymous with high-performance Subaru builds, and the M8250 is one of their most aggressive offerings. This turbocharger uses a custom-designed compressor wheel that flows air more efficiently than many comparable units. With a 66mm compressor inducer and a 58mm turbine wheel, the M8250 is capable of pushing over 350 horsepower on pump gas and can exceed 400 horsepower with ethanol blends.

The M8250 employs a journal bearing system (not dual-ball bearing), which is chosen for its durability under high heat and high boost conditions. Spool starts around 3800–4200 rpm, making it a bit laggier than the other options listed, but the reward is substantial top-end airflow that keeps pulling to redline. This turbocharger is best suited for a heavily modified WRX with upgraded fuel system (larger injectors, fuel pump, and possibly flex-fuel), a front-mount intercooler, and a built engine if you plan to run high boost levels.

Owners report excellent results on E85, where the M8250's high flow capacity really shines. The Tomei comes with a 10cm² turbine housing, which is optimized for Subaru's unequal-length header design. Expect to need a custom calibration from a professional tuner. Because of its high flow, the M8250 can stress the stock internals beyond 400 horsepower, so a forged piston and rod kit should be considered if reliability is paramount.

5. Forced Performance FP Black Turbocharger

The Forced Performance FP Black is the heavy hitter of the bunch. Engineered for maximum power, this turbocharger uses a billet compressor wheel and a high-flow turbine wheel to produce north of 400 wheel horsepower with appropriate supporting modifications. The FP Black is a frequent choice for WRX owners aiming for 450–500 horsepower on a built engine.

The turbo features a 71mm HTA (High-Tech Aero) compressor inducer and a 65mm turbine wheel, housed in a 0.85 A/R turbine housing. Spool occurs around 4000–4500 rpm, which means the power comes on strong but later than a more modest upgrade. On a 2.5L engine, the FP Black can still deliver a thrilling mid-range punch, while on a 2.0L it will feel more like a top-end monster.

To safely run an FP Black, you will need a full suite of supporting mods: upgraded fuel system (1000cc+ injectors, upgraded fuel pump, and possibly surge tank), a front-mount intercooler, 3-inch turbo-back exhaust, and a built short block with forged pistons and rods. A stand-alone engine management system or a Cobb Accessport with a professional dyno tune is essential. The FP Black is not a “bolt-on and go” upgrade; it is for serious builds where massive power is the goal. When properly tuned, it offers exceptional reliability for its output level.

Essential Supporting Modifications for Any Turbo Upgrade

Installing a larger turbo without upgrading the supporting systems is a recipe for disappointment or, worse, engine failure. At a minimum, plan for the following parts when going from 270 to 350+ horsepower:

  • Fuel System: The stock fuel pump and injectors will run out of capacity. Upgrade to a higher-flow pump (e.g., AEM 340) and injectors sized 750cc or larger. For Ethanol blends, consider 1000cc+ injectors.
  • Intercooling: The stock top-mount intercooler becomes heat-soaked quickly. A larger top-mount or a front-mount intercooler (FMIC) is recommended for any turbo larger than the stock VF52.
  • Exhaust: A catted or catless downpipe and a cat-back exhaust with a 3-inch diameter will reduce backpressure and allow the turbo to flow freely.
  • Intake: A high-flow intake (e.g., Cobb SF Intake or Process West) helps the turbo breathe and can improve spool time.
  • Engine Management: An Accessport by Cobb Tuning is the most common platform for tuning a WRX. Access to a professional tuner is critical for safe air/fuel ratios and timing.

If you push toward the 400-plus horsepower range, internal engine modifications such as forged pistons, connecting rods, and upgraded valve springs become necessary to handle the increased cylinder pressure.

Tuning Considerations

Regardless of which turbo you choose, a proper tune is non-negotiable. The factory ECU calibration cannot adapt to the increased airflow of a larger turbo. Using an Accessport or a stand-alone ECU (like a Haltech or ECUTek) allows a tuner to adjust fuel, spark, boost, and wastegate duty cycles. Always seek out a tuner who has experience tuning Subarus with the specific turbo you are using. Many owners find that pro-tuner results on a dyno provide the most reliable and powerful calibration compared to off-the-shelf maps.

For those on a budget, e-tuning via data logs is also a viable option and has yielded excellent results with the turbos listed above. Monitor knock, fuel trims, and boost targets carefully after installation.

Reliability and Long-Term Expectations

Adding 80–130 horsepower over stock inevitably increases stress on the engine. The Subaru FA20 and EJ25 are tough engines, but they have limits. With a proper tune and quality parts, the GTX2860R or Blouch 20G can provide tens of thousands of miles of reliable service. The more aggressive FP Black or Tomei M8250 require a higher level of maintenance and a built engine to avoid failure. Service intervals for oil changes should be reduced (every 2500–3000 miles), and using a high-quality synthetic oil is essential for turbo longevity.

Consider upgrading the oil pickup tube and baffles to avoid starvation in hard corners, especially if you plan to track the car. An oil cooler is also a smart addition for sustained high-boost driving.

Conclusion

Upgrading the turbocharger on your Subaru WRX is the single most effective way to transform its character from a peppy daily driver to a serious performance machine. The five turbos highlighted here – the Garrett GTX2860R, Blouch 20G, IHI VF48, Tomei M8250, and Forced Performance FP Black – offer a clear progression in power, spool characteristics, and required investment. Choose the one that aligns with your power goals, budget, and willingness to support the upgrade with proper parts and tuning. With the right combination, you can confidently push your WRX from 270 to 350+ horsepower and enjoy a thrilling, reliable driving experience for years to come.