Why Forced Induction on the Lexus IS300?

The Lexus IS300, with its iconic 2JZ-GE engine, offers a reliable and smooth platform that begs for more power. While the naturally aspirated 2JZ is praised for its durability, it leaves significant untapped potential. A properly selected turbo kit transforms the IS300 from a comfortable daily driver into a serious performer. Forced induction not only increases horsepower but also dramatically improves torque delivery, making the car more responsive and fun to drive. However, not all turbo kits are created equal. Performance gains, build quality, price, and ease of installation vary widely. This guide breaks down the top five turbo kits from forced induction experts, comparing power outputs, costs, and key features to help you choose the right setup for your goals and budget.

Before diving into specific kits, it’s important to understand that adding a turbocharger to an IS300 requires careful preparation. The stock fuel system, engine management, and cooling can become limiting factors. Many kits include essential components like intercoolers, wastegates, blow-off valves, and upgraded fuel injectors, but you should always plan for supporting modifications and professional tuning. The horsepower figures listed are realistic maximums achieved with proper supporting mods and a quality tune on pump gas (93 octane).

1. GReddy Turbo Kit

GReddy has long been a trusted name in Japanese performance, and their turbo kit for the IS300 (also sold as the JZA80 Supra kit with modifications) remains a benchmark for quality and reliability. This kit is engineered to bolt onto the 2JZ-GE with minimal fabrication, making it a favorite among enthusiasts who want a straightforward installation. The GReddy kit uses a T67-25G turbocharger, which provides excellent mid-range power without sacrificing top-end pull.

Key Components

  • GReddy T67-25G turbocharger (0.84 A/R)
  • Cast iron exhaust manifold
  • Wastegate and blow-off valve (often GReddy Type R or Type S)
  • Front-mount intercooler with piping
  • Oil feed and drain lines
  • Downpipe and intake piping

Power Gains and Real-World Performance

With the GReddy kit and proper tuning, IS300 owners consistently report gains from stock (around 215 hp at the crank) to over 300 wheel horsepower. Many achieve 320-340 wheel horsepower on 93 octane with a conservative tune. The torque curve is broad and usable, with boost onset around 3000 RPM and full spool by 3800 RPM. Reliability is excellent when paired with a quality engine management system like an AEM EMS, Haltech, or a standalone ECU.

Pricing and Final Verdict

Price: Approximately $3,500-$4,000 (kit only, tuning and supporting mods extra)

The GReddy kit is an excellent choice for those seeking a proven, reliable setup. Its cast manifold reduces warping risk, and the T67 turbo is a classic choice for the 2JZ. However, the kit is somewhat older in design, and sourcing new units can be challenging. Expect to add $1,000-$1,500 for a standalone ECU, fuel system upgrades, and professional tuning. This kit typically delivers 300-340 RWHP safely.

External link: GReddy Performance Products

2. HKS Turbo Kit

HKS is another legendary Japanese tuning company, and their turbo kit for the IS300 (often referred to as the HKS GT3037 or HKS GT2835 kit depending on the generation) is designed for maximum performance without compromise. HKS components are known for precision engineering and durable construction, making this kit a premium option. The kit typically uses an HKS GT3037S turbo, which is capable of supporting up to 400 wheel horsepower with the right supporting mods.

Key Components

  • HKS GT3037S ball-bearing turbocharger
  • HKS cast exhaust manifold (or stainless steel, depending on version)
  • HKS wastegate and blow-off valve
  • Large front-mount intercooler with aluminum piping
  • Comprehensive hardware, gaskets, and installation instructions

Power Gains and Tuning Potential

HKS rates this kit for up to 320 horsepower at the crank, but with proper fuel and tuning, many owners see 350-380 wheel horsepower. The ball-bearing turbo spools faster than journal bearing units, providing boost as early as 3200 RPM. The power delivery is smooth, making the car feel significantly quicker throughout the rev range. Because HKS components are modular, upgrading the turbo to a larger unit down the road is possible without replacing the entire setup.

Pricing and Considerations

Price: Approximately $4,200-$4,800

The HKS kit commands a premium for its name and engineering excellence. It includes high-quality gaskets and hardware, which reduces the chance of leaks. Installation is straightforward but requires careful routing of intercooler piping on the IS300 chassis. You will need a standalone ECU and upgraded fuel pump/injectors to realize the full potential. Many shops recommend the HKS kit for those who plan to build the engine later, as the turbo can support a 2JZ-GTE head gasket and ARP studs.

External link: HKS Official Site

3. AEM Turbo Kit

AEM (Advanced Engine Management) is well-known for its engine management systems, but their turbo kits offer a complete package focused on reliability and value. The AEM turbo kit for the IS300 is less common than the GReddy or HKS kits but represents a solid entry-level forced induction solution. It uses a Garrett GT3071R turbo (or similar AEM-spec unit), which is robust and well-supported.

Key Components

  • AEM/Garrett GT3071R turbocharger
  • Stainless steel exhaust manifold
  • AEM in-house wastegate and blow-off valve
  • Bar-and-plate front intercooler
  • Pre-bent mandrel piping
  • Oil line kit

Power Gains and Value

AEM states this kit can produce up to 280 horsepower at the wheels on a conservative tune with 93 octane. However, many users have reported 300-320 wheel horsepower after refining the tune and adding a boost controller. The GT3071R turbo is a known performer, capable of supporting 400+ wheel horsepower with a larger exhaust housing. The kit is designed to work with AEM’s own engine management, which simplifies tuning. The price point makes it an attractive option for budget-conscious builders.

Pricing and Limitations

Price: Approximately $2,800-$3,300

While the AEM kit is affordable, it does not include a standalone ECU, injectors, or a fuel pump. You will need to budget at least $1,500 for an AEM EMS-4 or EMS-2, plus injectors and a fuel pump. The stainless steel manifold can crack over time with high heat cycles, though this is a common issue with many turbo manifolds. If you are looking for a solid base to build upon, the AEM kit is a strong contender.

External link: AEM Performance Electronics

4. Precision Turbo Kit

Precision Turbo and Engine is a U.S.-based company with a stellar reputation for high-performance turbochargers. Their turbo kit for the IS300 is often a custom or semi-custom affair, but several vendors offer complete Precision-based kits. Typically, these kits use a Precision Journal Bearing or Ball Bearing turbo, such as the PT5858 or PT6262, which are known for their efficiency and ability to handle high boost.

Key Components

  • Precision PT5858 or PT6262 turbocharger (choice of A/R)
  • Custom tubular or cast exhaust manifold (sourced from various fabricators)
  • Tial wastegate (included in most quality kits)
  • Tial blow-off valve
  • High-quality intercooler core with silicone hoses

Power Gains and Engine Safety

With the Precision PT5858, owners typically achieve 350-400 wheel horsepower on 93 octane and about 450 wheel horsepower on E85 with the proper fuel system. The PT6262 can push beyond 500 wheel horsepower, but this requires built internals (rods, pistons, head studs) and a standalone ECU. Precision turbo kits are often chosen by those planning to upgrade the bottom end eventually. The reliability is high when properly tuned, but the kit’s price reflects the quality of the components.

Pricing and Availability

Price: Approximately $4,500-$5,500 (complete kit, depending on turbo size and manifold choice)

Precision-based kits are less of a “one-box” solution and more of a curated combination. Many suppliers like Sound Performance (SP) or Raptor Racing offer complete packages. Be prepared to spend extra for a quality standalone ECU, upgraded fuel system, and professional installation if you are not experienced. The Precision kit is best for those who want a serious power upgrade and plan to support it with extensive modifications.

External link: Precision Turbo and Engine

5. Full Race Turbo Kit

Full Race is renowned for its high-quality, race-oriented turbo manifolds and complete systems. Their turbo kit for the IS300 (often based on the 2JZ platform) is a premium choice that leaves little to be desired in terms of performance and engineering. The kit uses a Full Race proprietary turbo manifold and pairs it with a BorgWarner EFR turbocharger or a Garrett GTX series, depending on the customer’s choice. The EFR turbochargers are known for their integrated wastegate and recirculation valve, simplifying installation and improving reliability.

Key Components

  • Full Race tubular stainless steel exhaust manifold (T4 or T3 flange)
  • BorgWarner EFR 6758, 7064, or 7670 turbo (or Garrett GTX3071R/GTX3076R)
  • Integrated recirculation valve (on EFR turbos)
  • Custom downpipe
  • Intercooler piping (often V-band connections)
  • Full Race intercooler core (bar-and-plate, high-flow)

Power Gains and Top-End Performance

The Full Race kit is built for big power. Even with the smaller EFR 6758, you can expect 350-400 wheel horsepower with a safe tune. The EFR 7670 can support up to 650 wheel horsepower on built engines. The tubular manifold design reduces turbo lag compared to cast manifolds, especially with the EFR’s quick-spool turbine. This kit demands excellent fuel delivery and tuning; most owners pair it with a Syvecs, Haltech, or MoTeC ECU.

Pricing and Target Audience

Price: Approximately $5,500-$7,000 (complete kit with turbo)

This is the most expensive kit on the list, but it offers the highest quality components, the best spool characteristics, and the greatest power potential. Full Race provides excellent technical support. The kit is not for beginners; you need a built engine and fuel system to take full advantage. If your goal is 500+ wheel horsepower and you have the budget, the Full Race kit is the ultimate choice.

External link: Full Race Motorsports

Comparison Summary: Power, Price, and Purpose

Choosing a turbo kit involves trade-offs. Here is a quick reference table to compare the five kits:

  • GReddy – 300-340 RWHP / ~$3,500 / Proven reliability, simple install. Good for daily drivers.
  • HKS – 350-380 RWHP / ~$4,500 / Premium engineering, ball-bearing turbo. Good for enthusiasts wanting a safe upgrade path.
  • AEM – 280-320 RWHP / ~$2,800 / Budget-friendly, solid foundation. Needs separate ECU.
  • Precision – 350-500+ RWHP / ~$4,500-$5,500 / High potential, modular. Best for builders.
  • Full Race – 400-650+ RWHP / ~$5,500-$7,000 / Top-tier performance, fastest spool. For serious power seekers.

Essential Supporting Mods for Any Turbo Kit

Regardless of which turbo kit you choose, the following modifications are highly recommended (or required) to ensure reliability and performance:

  • Engine Management: A standalone ECU (AEM, Haltech, Link, MoTeC) is essential for controlling fuel, ignition, and boost. The stock IS300 ECU cannot handle forced induction.
  • Fuel System: Upgraded injectors (550-1000cc depending on power goals), a higher-flow fuel pump (Walbro 450 or AEM 340), and a fuel pressure regulator.
  • Intercooling: Most kits include a front-mount intercooler, but ensure it is efficient for your power level.
  • Exhaust: A 3-inch turbo-back exhaust system reduces backpressure and helps spool.
  • Cooling: An upgraded radiator and oil cooler are recommended for sustained high-performance driving.
  • Drivetrain: The IS300 automatic transmission may need reinforcement (or a manual swap) above 400 wheel horsepower. The manual transmission (W55/W58) should be upgraded to an R154 or CD009 for 450+ wheel horsepower.

Installation Considerations and Tuning Costs

Installing a turbo kit on an IS300 is a complex project requiring mechanical skill, welding, and electrical knowledge. Many owners choose professional installation, which can cost $1,000-$2,500 depending on the shop. Tuning costs range from $500 to $1,500 for a street tune or $1,500-$3,000 for a dyno tune with a reputable tuner. Do not skip proper tuning—a bad tune can destroy the engine quickly.

Conclusion

The Lexus IS300 is one of the most rewarding cars to turbocharge, thanks to its bulletproof 2JZ engine and vast aftermarket support. The five turbo kits covered here represent the best options available from forced induction experts, each tailored to different budgets and performance goals.

If you want a reliable daily driver with a noticeable power increase, the GReddy kit offers proven performance at a reasonable price. For those who value brand prestige and a ball-bearing turbo, the HKS kit is a premium step up. Budget-minded builders will appreciate the AEM kit as a solid starting point. Enthusiasts planning a high-horsepower build should consider the Precision kit for its cost-per-horsepower value. And if nothing but the best is acceptable and you have deep pockets, the Full Race kit delivers unrivaled quality and power potential.

Remember that the turbo kit is just the beginning. Factor in the cost of a standalone ECU, fuel system upgrades, tuning, and possibly engine and drivetrain reinforcement. A well-planned build with a matched turbo kit will result in a reliable, exhilarating IS300 that can compete with modern sports cars. Research thoroughly, consult with experienced builders, and enjoy the process of transforming your Lexus into a forced-induction legend.