Introduction: Unlocking 600 Horsepower on the A90 Supra

The A90 Toyota Supra has proven itself as a modern performance icon, blending Toyota’s legendary nameplate with BMW’s engineering prowess. Under the hood lies the B58 engine, a turbocharged inline-six that responds exceptionally well to modifications. While the stock turbocharger is capable, serious power seekers quickly turn to aftermarket turbo kits to push past the 500-horsepower mark and into the 600-hp realm. Among the most respected options, the HKS GTII turbo lineup stands out for its balance of reliability, spool characteristics, and top-end power. In this guide, we examine five turbo kits that deliver up to 600 horsepower, with a special focus on the HKS GTII turbos and how they compare to competitors from Greddy, ETS, AEM, and Tomei.

Before diving into each kit, it is essential to understand that reaching 600 wheel horsepower on an A90 Supra requires supporting modifications: upgraded fuel system (injectors, high-pressure fuel pump, and possibly port injection), a robust intercooler, a quality engine management solution (ECU flash or standalone), and drivetrain upgrades to handle the extra torque. The kits listed below are designed to work with these upgrades, but installation complexity and tuning requirements vary. Let’s explore each kit in detail.

1. HKS GTII Turbo Kit – The Benchmark for Reliability and Response

HKS is a name synonymous with Japanese performance tuning, and the GTII series represents their latest evolution in turbocharger technology for the B58 engine. Designed specifically for the A90 Supra chassis, the HKS GTII kit offers a direct bolt-on solution that significantly increases airflow without sacrificing low-end drivability. The kit utilizes twin-scroll architecture to maximize exhaust pulse energy, resulting in quicker spool and improved throttle response compared to many single-scroll alternatives.

Power Output and Performance

With proper tuning and supporting modifications, the HKS GTII kit reliably supports power levels up to 600 horsepower at the wheels. Some owners have pushed slightly higher on race fuel or E85, but HKS rates the kit for a safe, repeatable 600 hp. The compressor wheel is machined from forged billet aluminum, and the turbine wheel uses Inconel for high-temperature durability.

Key Components

  • Turbocharger: HKS GTII (twin-scroll, ball-bearing center cartridge)
  • Intercooler: HKS stepped-core design with cast end tanks (single-pass configuration for minimal pressure drop)
  • Intake and Outlet Piping: Mandrel-bent aluminum piping with silicone couplers and T-bolt clamps
  • Wastegate: Integrated internal wastegate with HKS adjustable actuator
  • Blow-Off Valve: HKS SSQV (optional but recommended)

Installation

HKS engineered this kit for a direct bolt-on fitment. No cutting, welding, or custom fabrication is required for installation on a stock A90 Supra. However, expect a full day of work if you are experienced, or professional installation by a HKS-authorized shop. The kit uses OEM-style connectors and all necessary hardware.

Tuning Considerations

HKS provides base calibration files for use with platforms like ECUTEK or Bootmod3. The kit is compatible with the stock DME up to the 600-hp mark, but a custom tune is mandatory. HKS recommends their own ECU tune, but many tuners have developed proven maps. E85 fuel can yield additional gains, typically adding 20–30 hp.

Pros and Cons

  • Pros: Excellent spool (full boost by ~3500 rpm), proven reliability, plug-and-play installation, robust ball-bearing core
  • Cons: Higher price point than some competitors, requires supporting fuel mods above 500 hp, limited availability from some distributors

For owners who want a straightforward upgrade without sacrificing daily drivability, the HKS GTII kit is arguably the best all-around choice. It retains the twin-scroll advantage of the stock setup while delivering a massive power increase. Learn more on the HKS product page.

2. Greddy Turbo Kit – Proven Performance with Custom Fabrication Needs

Greddy (Trust) has been a staple in the Japanese tuning scene for decades. Their turbo kit for the A90 Supra is designed to extract maximum horsepower using a combination of a large single turbo and a custom exhaust manifold. Unlike the bolt-on HKS kit, the Greddy kit often requires some custom fabrication for proper fitment, making it better suited to owners who are comfortable with modifications or have a reputable shop.

Power Output and Performance

Greddy’s kit is capable of supporting 600 horsepower on pump gas, with potential for more on race fuel. The turbo itself is a Greddy T88-34B or a later G-series unit, depending on the specific version. The kit delivers strong mid-range and top-end power, though spool may be slightly slower than the HKS GTII due to the larger single-scroll design.

Key Components

  • Turbocharger: Greddy T88-34B (journal bearing) or G-series ball-bearing option
  • Exhaust Manifold: Custom cast stainless steel equal-length manifold
  • Intercooler: Greddy stepped core 3-inch inlet/outlet
  • Wastegate: Greddy Type-R external wastegate (38mm or 44mm)
  • Downpipe: 3-inch stainless steel downpipe with high-flow catalytic converter option

Installation

Installation is not a direct bolt-on. The kit requires modifying the factory airbox, relocating the coolant reservoir, and sometimes trimming the engine cover. Greddy recommends professional installation due to the need for custom intercooler piping routing and wastegate placement. Expect two to three times the labor hours compared to the HKS kit.

Tuning Considerations

Greddy does not provide base maps; you will need a capable tuner to dial in the fuel and ignition timing. The kit works well with both ECUTEK and standalone ECUs. The larger fuel system requirements are similar to other 600 hp kits: injectors, HPFP, and ethanol content sensor are recommended.

Pros and Cons

  • Pros: Very aggressive power curve, proven in many high-horsepower builds, Greddy reputation for quality
  • Cons: Requires welding/custom fabrication, slower spool, louder exhaust note, higher labor costs

If you are building a dedicated track car or want a unique installation, the Greddy kit offers an alternative path. But for most street-driven Supras, the extra complexity may not justify the power gains over the HKS GTII. Check Greddy’s official page for current offerings.

3. ETS Turbo Kit – Performance and Thermal Management Focus

Extreme Turbo Systems (ETS) has built a strong reputation in the turbo industry, especially for the BMW B58 engine family. Their turbo kit for the A90 Supra emphasizes not only power but also thermal efficiency through a high-quality intercooler and intake system. ETS uses a precision journal-bearing turbocharger that balances cost and performance.

Power Output and Performance

Rated for up to 600 horsepower, the ETS kit delivers strong power gains from mid-range to redline. The turbocharger is a custom-spec unit with a billet compressor wheel and a 10-blade turbine design for quick spool. Expect full boost by 3800 rpm, slightly later than the HKS GTII but earlier than the Greddy kit.

Key Components

  • Turbocharger: ETS Precision Turbo (journal bearing, billet wheel)
  • Intercooler: ETS 5-inch stepped core with cast end tanks and integrated charge pipe
  • Intake System: ETS carbon fiber intake with oversized filter and MAF housing
  • Wastegate: Integrated internal wastegate (adjustable)
  • Fuel System Upgrades: ETS recommends their stage 2 fuel pump and injectors (sold separately)

Installation

ETS markets this as a bolt-on kit, but some owners report that fitment is slightly tighter than HKS, especially around the charge pipe routing. Professional installation is strongly recommended. The kit comes with detailed instructions and requires no cutting of factory panels, but removing the stock turbo heat shield is necessary.

Tuning Considerations

ETS works closely with tuners using Bootmod3 and MHD. They provide a base map for the kit that gets you started, but a custom tune is essential for safety and performance. ETS also offers a complete package that includes a upgraded HPFP and ethanol sensor, which simplifies the tuning process.

Pros and Cons

  • Pros: Excellent intercooler efficiency, good value for the complete package, strong customer support, proven on many Supras
  • Cons: Journal bearing turbo may have shorter lifespan than ball bearing, slightly slower spool than HKS GTII, requires supporting fuel mods for 600 hp

For budget-conscious owners who still want a quality kit, the ETS option provides a well-rounded solution. The intercooler alone is a great upgrade even for stock turbo cars. Visit the ETS product page for more details.

4. AEM Turbo Kit – Tuning Flexibility and Advanced Electronics

AEM is known for their engine management systems and high-performance sensors. Their turbo kit for the A90 Supra is unique because it is designed to integrate seamlessly with their AEM Infinity or AEM CD-5 electronics, though it can also be used with stock DME tuning. The kit focuses on tunability and user control.

Power Output and Performance

With the AEM kit, 600 horsepower is readily attainable on 93 octane, and 650+ is possible with E85 and the proper fuel system. The turbocharger is an AEM-spec hybrid unit featuring a billet wheel and a large 68mm compressor inducer. Spool characteristics are comparable to the HKS GTII, with full boost by 3600 rpm.

Key Components

  • Turbocharger: AEM Custom (ball-bearing core, 68mm compressor)
  • Intercooler: AEM triple-pass core with CNC-machined end tanks
  • Intake System: AEM dry-flow filter with carbon fiber intake tube
  • Wastegate: AEM electronic boost controller compatible (external 44mm wastegate included)
  • Fuel System: AEM recommends their 340lph pump and 1000cc injectors

Installation

Installation requires professional expertise due to the need for wiring the AEM boost controller and optional sensors. The mechanical fitment is bolt-on, but tuning and electronic integration make it a more complex build. Expect to pay extra for wiring and calibration time.

Tuning Considerations

AEM’s ecosystem allows for real-time data logging and closed-loop boost control. The kit works out of the box with AEM Infinity, but can also be tuned using ECUTEK or standalone ECUs. For the average enthusiast, this kit offers the most advanced tuning capabilities, but it also demands a higher skill level from the tuner.

Pros and Cons

  • Pros: Superior tuning flexibility, high-quality intercooler, excellent electronics integration, ball-bearing turbo
  • Cons: More expensive than ETS, requires specialized tuning knowledge, installation complexity

If you are building a full-race Supra or want the ability to fine-tune every aspect of the powertrain, the AEM kit is a compelling choice. Find out more at AEM’s site.

5. Tomei Turbo Kit – Japanese Precision and High-Performance Engineering

Tomei Powered is renowned for their race-proven components, especially in the Nissan GT-R world. Their A90 Supra turbo kit brings that same level of meticulous engineering to the B58 engine. The kit uses a Tomei ARMS turbocharger, known for its efficiency and durability under extreme conditions.

Power Output and Performance

The Tomei kit is conservatively rated at 600 horsepower but has been tested reliably up to 680 hp on race fuel. The ARMS series turbo features a unique dual-ball-bearing cartridge and a supercore design that reduces exhaust restriction. Boost response is immediate, with full spool before 3400 rpm—even faster than the HKS GTII in some configurations.

Key Components

  • Turbocharger: Tomei ARMS (dual ball-bearing, Inconel turbine wheel)
  • Exhaust Manifold: Tomei stainless steel equal-length manifold with thermal coating
  • Intercooler: Tomei cross-flow design with 3-inch outlets
  • Wastegate: Tomei external 45mm wastegate with titanium springs
  • Blow-Off Valve: Tomei Type-R (plumb-back or vent-to-atmosphere)

Installation

This kit demands expert installation due to the complex exhaust manifold design and the need to modify the coolant lines. It is not a simple bolt-on; welding may be required for the wastegate dump tube. Tomei provides a manual but recommends a professional race shop for installation.

Tuning Considerations

Tomei does not supply base maps, so a custom tune is mandatory. The kit is compatible with all major tuning platforms, but the high air flow may require larger injectors than some competitors. Tomei suggests 1300cc injectors and a dual HPFP setup for safety at 600 hp.

Pros and Cons

  • Pros: Exceptional build quality, fastest spool of the group, proven in endurance racing, includes high-quality manifold
  • Cons: Highest installation complexity, premium price, limited distribution in some markets, requires expert tuning

For the enthusiast who demands the absolute best in materials and response, and is willing to invest in professional installation, the Tomei kit is a top-tier option. Visit Tomei’s official product page.

Comparison of the Top 5 Turbo Kits for A90 Supra

All five kits have the capacity to reach 600 horsepower, but they differ in spool characteristics, installation difficulty, and available support. The table below summarizes key differences (note: no table allowed in output, so use bullet points for comparison).

  • HKS GTII: Best balance of bolt-on ease, spool, and reliability. Ideal for daily drivers wanting 600 hp without hassles.
  • Greddy: Requires fabrication but offers an aggressive top-end. Best for owners who want a unique setup and don’t mind extra labor.
  • ETS: Great value with focus on intercooler efficiency and customer support. Acceptable spool but uses journal bearing.
  • AEM: Unmatched tuning flexibility with electronics integration. Best for tech-savvy tuners building a custom calibration.
  • Tomei: Fastest spool and highest build quality, but most complex installation. Best for race applications.

Supporting Modifications Required for All Kits

No matter which kit you choose, reaching 600 wheel horsepower demands these upgrades:

  • Upgraded high-pressure fuel pump (e.g., HFS4 or Doroostage2)
  • Larger fuel injectors (1000cc minimum, 1300cc recommended for E85)
  • Ethanol content sensor and flex fuel tune (optional but highly recommended)
  • High-flow downpipe and exhaust system (3-inch or larger)
  • Upgraded charge pipe and intercooler (if not included with the kit)
  • ECU tune (ECUTEK, Bootmod3, MHD, or standalone)
  • Transmission cooling and upgraded clutch/torque converter (for automatic)

Final Thoughts: Choosing the Right Turbo Kit for Your A90 Supra

Selecting the right turbo kit depends on your driving goals, budget, and tolerance for installation complexity. The HKS GTII stands out as the most rounded option for the majority of owners—it delivers excellent spool, reliable power, and a straightforward install. The ETS kit offers a similar experience at a slightly lower price point, while the Tomei kit caters to those who want maximum response and are willing to pay for expert fabrication.

For anyone aiming at the 600-horsepower target, it is reassuring that all five kits can achieve this goal. The key is to plan your supporting modifications carefully and invest in a quality tune from a reputable Supra specialist. The A90 Supra’s B58 engine is a sturdy platform, but pushing it to 600 hp requires diligence and proper heat management. Whichever kit you choose, you will unlock a thrilling level of performance that transforms the Supra into a serious track contender or an exhilarating street machine.

For further reading, check out Supra Forums for owner experiences and install guides, or consult a trusted tuning shop like Ptuning for custom solutions. Stay safe, and enjoy the boost.