Why Upgrade Your Lexus IS300 with a Turbo Kit?

The Lexus IS300, powered by the legendary 2JZ-GE engine, is one of the most rewarding platforms for forced induction. While the naturally aspirated 2JZ delivers smooth power and renowned reliability, adding a turbocharger transforms the car into a genuine performance machine capable of competing with modern sports sedans. In 2024, the aftermarket support for the IS300 remains strong, with several turbo kits designed to push wheel horsepower from the factory 250whp range well past 400whp.

Choosing the right turbo kit requires understanding your power goals, budget, and how much fabrication you are willing to tackle. Some kits bolt on with minimal fuss, while others demand professional installation and supporting modifications like upgraded fuel systems, intercoolers, and standalone engine management. Below, we break down the top five turbo kits available this year, each with unique strengths for different types of builders.

1. Greddy Turbo Kit – The Reliable Workhorse

Greddy has been a household name in the Japanese performance scene for decades, and their IS300 turbo kit remains a top seller for good reason. This kit is engineered specifically for the 2JZ-GE and delivers proven power gains without the headaches that come with piecing together a custom setup.

Power and Performance

The Greddy kit is capable of supporting up to 400whp on a stock internal 2JZ-GE, provided you have proper tuning and fuel system upgrades. The included Greddy T518Z turbocharger spools quickly, offering strong mid-range torque that makes the car feel significantly faster in daily driving situations. Many owners report hitting 350whp on pump gas with a safe tune, making this kit ideal for those who want a reliable street car that can still surprise more expensive machinery.

Installation and Fitment

One of the biggest selling points of the Greddy kit is its bolt-on design. The manifold, downpipe, and intercooler piping are all manufactured to factory tolerances, meaning you won't spend hours fighting with misaligned flanges or cutting bumper supports. A mechanically inclined enthusiast with basic tools can complete the installation over a weekend. Greddy provides detailed instructions, and the kit includes all necessary gaskets and hardware. For IS300 owners who want a straightforward path to 400whp without custom fabrication, the Greddy kit is hard to beat.

  • Power Output: Up to 400whp
  • Key Features: High-quality cast manifold, T518Z turbo, precision wastegate, full intercooler piping
  • Installation: Bolt-on design, moderate DIY skill level required
  • Best For: Street-driven cars prioritizing reliability and ease of installation

2. HKS GT Turbo Kit – Japanese Engineering Excellence

HKS is synonymous with high-performance Japanese tuning, and their GT turbo kit for the IS300 lives up to that reputation. This kit is designed for enthusiasts who demand the highest quality components and are willing to invest in a system that can grow with their power goals.

Turbocharger Technology

The HKS GT kit features the GT2835 or GT3037 turbocharger, depending on the specific version you choose. These turbos utilize HKS's advanced wheel technology to deliver excellent flow efficiency and durability. The GT2835 spools slightly faster and is perfect for a responsive 350-400whp setup, while the GT3037 can push closer to 500whp with the right supporting modifications. Both options feature a T3 flange and HKS's proprietary bearing system for long service life.

Build Quality and Materials

HKS uses high-grade stainless steel for the manifold and downpipe, ensuring resistance to cracking under the extreme thermal cycles of forced induction. The intercooler is a bar-and-plate design with cast end tanks, offering superior heat rejection compared to tube-and-fin designs found in cheaper kits. Every coupler and clamp included in the kit is sourced from HKS's industrial supply chain, meaning you won't be replacing silicone hoses after a year of use. This attention to detail makes the HKS kit a favorite among enthusiasts who plan to keep their IS300 for the long haul.

  • Power Output: Up to 400whp with GT2835, 500whp with GT3037
  • Key Features: Stainless steel manifold, HKS GT series turbo, high-flow intercooler
  • Installation: Requires some modification to factory piping and wiring
  • Best For: Enthusiasts who want a premium kit with expansion potential

3. Full Race Turbo Kit – Maximum Performance, Maximum Flow

Full Race Motorsports has built a reputation around high-horsepower turbo systems that push the boundaries of what is possible with the 2JZ platform. Their IS300 turbo kit is designed for serious builders who are not satisfied with 400whp and have their sights set on much higher numbers.

Engineering and Custom Options

Full Race offers their manifold and downpipe as a base, with the flexibility to pair with a wide range of turbochargers based on your specific goals. The manifold is constructed from thick-wall 304 stainless steel, TIG-welded by hand, and features a divided T4 flange that minimizes exhaust pulse interference. This design reduces turbo lag and allows for more efficient spool, especially when using larger frame turbos like the Precision 6266 or Garrett G35-1050. The kit also includes a Full Race intercooler with a large core that supports engines producing well over 600whp.

Installation Considerations

Unlike the Greddy kit, the Full Race system is not a simple weekend bolt-on. The manifold and downpipe require careful positioning, and you will likely need to relocate or modify the factory radiator fan shroud, power steering lines, and occasionally the AC compressor bracket. Professional installation is strongly recommended unless you have significant fabrication experience. However, for owners who are building a dedicated track car or a high-horsepower street monster, the flow characteristics of the Full Race kit provide a clear advantage over mass-produced cast manifolds.

  • Power Output: 400+ whp, capable of 800+ whp with larger turbos
  • Key Features: Hand-welded stainless manifold, T4 divided flange, customizable turbo options
  • Installation: Professional installation recommended
  • Best For: High-horsepower builds and track-focused vehicles

4. Precision Turbo Kit – Affordable Power Meets Proven Hardware

Precision Turbo & Engine is a name that resonates deeply in the American high-performance community. Their turbo kit for the IS300 offers a compelling value proposition, delivering serious power gains at a price point that undercuts many Japanese competitors.

The Precision Turbo Value

Precision uses their own PT6262 or PT6466 turbochargers, both of which are battle-tested in drag racing and street performance applications. The PT6262 is a 62mm unit that spools well and supports up to 450whp on a 2JZ-GE, while the PT6466 can push 550whp or more. Precision has optimized the compressor wheel design for high flow without sacrificing response, making these turbos a strong choice for street cars that occasionally see track time. The manifold is a cast iron unit that offers excellent heat retention and durability, though it is heavier than stainless steel alternatives.

Installation and Tuning

The Precision kit is straightforward to install, with most components bolting directly to the factory mounting points. The intercooler piping uses bead-lock couplers to prevent blow-off at high boost levels, and the included blow-off valve is adjustable for different boost pressures. One important consideration is that Precision kits are often sold as a base configuration, meaning you may need to purchase additional items such as a boost controller, wastegate spring, and fuel system upgrades separately. This a la carte approach allows you to customize the setup, but it also means the total cost can rise quickly if you are not careful.

  • Power Output: Up to 450whp with PT6262, 550whp with PT6466
  • Key Features: Cast iron manifold, Precision turbocharger, adjustable blow-off valve
  • Installation: Straightforward, some supporting parts sold separately
  • Best For: Budget-conscious builders who still want proven performance

5. AEM Turbo Kit – The Complete Turnkey System

AEM Electronics is known primarily for their engine management systems, but their turbo kit for the IS300 is a comprehensive package that leaves little to chance. Designed as a turnkey solution, this kit includes everything from the turbo manifold to the intercooler, piping, wastegate, and even a pre-calibrated AEM ECU in some versions.

Integrated Engine Management

The standout feature of the AEM kit is the inclusion of the AEM Series 2 or Infinity standalone ECU, pre-loaded with a base tune calibrated for the kit's hardware. This dramatically reduces the time and complexity associated with tuning, as the base map is safe enough to start the engine and drive to the dyno. The ECU also provides full control over fuel, ignition, boost, and auxiliary systems, giving you the flexibility to refine the tune later. For enthusiasts who are new to forced induction, the AEM kit removes much of the guesswork from the process.

Component Quality

The turbocharger in the AEM kit is a Garrett GT3582R, one of the most popular and well-supported turbos in the aftermarket. Garrett's reputation for consistency and performance is unmatched, and the GT3582R offers a broad power band that works well with the 2JZ-GE's displacement. The intercooler is a large bar-and-plate core with CNC-machined end tanks, and the piping uses silicone couplers with T-bolt clamps for secure connections. AEM also includes a billet wastegate and a high-flow blow-off valve, ensuring that boost control and surge protection are handled properly from day one.

  • Power Output: Up to 400whp
  • Key Features: Garrett GT3582R turbo, AEM standalone ECU, comprehensive hardware
  • Installation: User-friendly with base tune included
  • Best For: Enthusiasts seeking a complete, integrated solution

Supporting Modifications You Cannot Ignore

Installing a turbo kit is only half the battle. Reaching 400whp reliably on a 2JZ-GE requires attention to the fuel system, cooling, and drivetrain. The factory fuel injectors and fuel pump are insufficient for forced induction, so plan on upgrading to 550cc or larger injectors and a high-flow in-tank fuel pump. A standalone ECU or a piggyback fuel controller is essential to manage the increased fuel demand and adjust ignition timing. On the cooling side, consider an upgraded radiator, oil cooler, and possibly a transmission cooler if you are pushing the car hard on a track or during extended pulls. The factory automatic transmission in the IS300 is not particularly robust, so manual swaps or upgraded torque converters are common on high-horsepower builds.

Tuning for Safety and Performance

Regardless of which turbo kit you choose, professional tuning on a chassis dynamometer is the single most important step to ensure the longevity of your engine. A good tuner will dial in the air-fuel ratio, ignition timing, and boost curve to maximize power while keeping knock and exhaust gas temperatures within safe limits. Many shops offer remote tuning options if you have a compatible standalone ECU, but nothing beats having a skilled tuner adjust the calibration in real time as the car is loaded on the dyno. Expect to budget $500 to $1,000 for a professional tune, and do not skip this step even if the kit comes with a base map.

Final Thoughts on Choosing Your IS300 Turbo Kit

The Lexus IS300 is a car that rewards careful modification. Each of the turbo kits featured here has a distinct personality, from the bolt-in convenience of the Greddy kit to the raw performance potential of the Full Race system. Your choice should be guided by your power goals, your tolerance for fabrication work, and your budget for supporting modifications. For most street-driven cars aiming for 400whp, the Greddy or HKS kits offer the best balance of performance, reliability, and installation ease. If you are building a dedicated high-horsepower car and have the resources for professional fabrication, the Full Race or Precision kits will serve you well into the 500-800whp range. Whatever path you choose, invest in quality tuning, upgrade your fuel system, and enjoy the transformation of your IS300 into a genuine performance sedan.

For further reading on 2JZ engine building and turbo selection, consult resources like Pro Street Online's IS300 turbo guide and Lexus Parts Now's turbo FAQ for owner experiences and hardware compatibility. Always verify current pricing and availability directly with manufacturers, as supply chain conditions can affect lead times.