The Greddy TD06SL2-20G turbocharger is one of the most well-known forced induction upgrades for the non-turbo Lexus IS300 and its Toyota sibling, the Altezza. Designed to bolt onto the 2JZ-GE engine with the appropriate manifold kit, this turbo promises a dramatic increase in power while maintaining the refined character of the car. For enthusiasts seeking a proven, streetable power bump, the TD06SL2-20G has become a benchmark. But the question remains: exactly how much horsepower can you expect, and what does it take to get there?

What Is the Greddy TD06SL2-20G Turbocharger?

The Greddy TD06SL2-20G is a journal-bearing turbocharger from the trusted Japanese manufacturer. It belongs to the TD06 series, which is known for its robust construction and ability to flow high volumes of air. The “SL2” designates a specific compressor housing and wheel combination, while “20G” refers to the compressor wheel size. This turbo is a popular middle-ground choice for the 2JZ-GE: it spools quickly enough for daily driving yet supports substantial horsepower when pushed.

Typical specifications include a 60.0 mm inducer compressor wheel, a 68.0 mm turbine wheel, and a 10.5 cm² turbine housing (though variations exist). It is capable of flowing roughly 45–50 lb/min of air, which theoretically supports up to 450–500 horsepower at the flywheel. However, real-world results depend heavily on the engine platform, boost level, and supporting modifications. The Greddy TD06SL2-20G is often sold as part of a complete kit (manifold, wastegate, downpipe, intercooler piping) specifically for the IS300, simplifying installation.

The IS300’s 2JZ-GE Engine: A Baseline

Before adding boost, it is essential to understand the starting point. The Lexus IS300 (2001–2005) came equipped with the 2JZ-GE, a naturally aspirated 3.0-liter inline-six. Lexus rated it at 215 horsepower and 218 lb-ft of torque at the crank in stock form. On a chassis dyno, a well-maintained IS300 typically delivers 165–175 wheel horsepower and 180–190 wheel lb-ft of torque. The engine features a strong cast-iron block and forged connecting rods, but the pistons are cast aluminum and are a known weak point above roughly 400–450 wheel horsepower. The compression ratio is 10.5:1, which is high for turbocharging and necessitates proper fueling and timing control to avoid detonation.

Despite these limitations, the 2JZ-GE is an excellent platform for turbocharging. The block can handle substantial power, and the bottom end is durable as long as knock is kept in check. Many enthusiasts have successfully run the Greddy TD06SL2-20G on a stock internal engine for years at moderate boost levels.

Real-World Horsepower Gains

Horsepower gains from the Greddy TD06SL2-20G on an IS300 vary widely based on boost pressure, supporting modifications, and tuning quality. Below are common dyno-verified results categorized by boost level.

Low Boost (6–8 psi)

At low boost, the turbo barely works, but the gains are still transformative. With a basic tune and minimal supporting mods (a front-mount intercooler, 2.5-inch exhaust, and upgraded fuel pump), owners report 280–300 wheel horsepower and 290–310 wheel lb-ft of torque. That represents roughly a 110–130 whp increase over stock. The 2JZ-GE’s high compression helps low-end response, and spool is quick—full boost arrives by 3,200–3,500 RPM. This is a safe, reliable setup suitable for daily driving.

Medium Boost (10–12 psi)

Stepping up to 10–12 psi requires a more comprehensive upgrade path: larger fuel injectors (e.g., 550–650 cc), a quality intercooler, a 3-inch exhaust, and a professional dyno tune. At this level, the Greddy TD06SL2-20G delivers 330–370 wheel horsepower and 350–380 wheel lb-ft of torque. The turbo is operating near its efficiency island, and the car pulls hard from 3,500 RPM to redline. Many owners consider this the sweet spot for a street-driven IS300—fast enough to embarrass many modern sports cars, yet still reliable if the tune is conservative.

High Boost (14–18+ psi)

Pushing beyond 14 psi on the stock engine is risky. At 15–16 psi, wheel horsepower can reach 400–430, and torque can exceed 400 lb-ft. However, the cast pistons become a ticking time bomb. To run these power levels safely, a built bottom end (forged pistons and rods) is mandatory. With a built engine and race fuel or E85, the Greddy TD06SL2-20G can produce 450–480 wheel horsepower. At this point, the turbo is near its flow limit, and the car becomes a handful. Most IS300s at this level are primarily used for track days or drag racing.

Note: All figures above are approximations based on publicly available dyno sheets from reputable IS300 tuning shops. Actual results depend on altitude, ambient temperature, fuel quality, and dyno calibration.

Factors That Influence Power Output

Several variables determine whether your IS300 will hit the lower or higher end of the gain spectrum.

  • Engine Tuning – A poor tune can leave 30–50 horsepower on the table or, worse, cause detonation and engine failure. Custom tuning via ECUs like AEM, Haltech, or Link is strongly recommended. Avoid generic “off-the-shelf” maps.
  • Fuel Quality – Pump gas with 91–93 octane is adequate up to about 12 psi. For higher boost, E85 or a mixture with race fuel allows more aggressive timing and higher power.
  • Intercooling Efficiency – A restrictive or undersized intercooler raises intake air temperatures, reducing power and increasing knock risk. A large front-mount intercooler with proper ducting is essential.
  • Exhaust Back Pressure – A 2.5-inch exhaust may suffice for 300 whp, but 3 inches is recommended for any setup exceeding 350 whp. A free-flowing downpipe and high-flow catalytic converter (or test pipe) also help.
  • Drivetrain Loss – The IS300’s automatic transmission (if equipped) saps more power than the 5-speed manual or a W58 swap. Dyno numbers for automatic cars are typically 10–15% lower.

Essential Supporting Modifications

A turbocharger is only as good as the system it lives in. To unlock the Greddy TD06SL2-20G’s potential safely, the following upgrades are highly recommended.

  • Upgraded Fuel Pump – A Walbro 255 lph or DW300 pump ensures adequate fuel delivery at boost.
  • Bigger Fuel Injectors – 550 cc injectors are the minimum for 350 whp; 650–750 cc are needed for 400+ whp.
  • Standalone ECU or Piggyback – The factory ECU cannot cope with boost. An AEM Infinity, Haltech Elite, or Link G4+ provides full control. For simpler setups, a piggyback like the Greddy e-Manage Ultimate works, but standalone is superior.
  • Front-Mount Intercooler – A core sized for 400–500 hp keeps intake temperatures in check. Greddy’s own kit includes a large intercooler, or aftermarket units from Treadstone or CSF are popular.
  • High-Performance Exhaust – A 3-inch stainless steel cat-back exhaust with a high-flow downpipe minimizes back pressure.
  • Oil Cooling – The turbo adds heat to the oil system. An oil cooler (e.g., Setrab or Mocal) is wise for sustained high-speed driving.
  • Boost Controller – A manual or electronic boost controller gives precise control over boost levels.

Installation and Tuning Considerations

Installing a Greddy TD06SL2-20G kit is not a weekend job for the inexperienced. It requires moderate to advanced mechanical skills, including fabrication work for intercooler piping and oil/coolant lines. Many owners opt for professional installation to ensure everything fits correctly and there are no leaks.

Common installation pitfalls include:

  • Insufficient oil drain line routing – the turbo must drain freely; any restriction causes seal failure.
  • Improper wastegate line routing – a boost creep issue that can cause overboost.
  • Inadequate cooling system – the added heat may require a higher-flow thermostat or electric fans.

Tuning should be performed on a dyno by a professional familiar with the 2JZ-GE. Expect 4–6 hours of tuning to dial in fuel maps, timing, and boost control. A good tuner can extract maximum power while keeping air-fuel ratios safe and knock at zero.

Budget and Cost Breakdown

The total investment to properly boost an IS300 with the Greddy TD06SL2-20G can range from $3,500 to $8,000+ depending on the scope of work. Here is a rough estimate:

  • Greddy TD06SL2-20G turbo kit (manifold, downpipe, piping, intercooler, etc.) – $2,000–$2,500
  • Fuel system upgrades (pump, injectors, lines) – $500–$1,000
  • Exhaust system (3-inch) – $600–$1,200
  • Standalone ECU and tuning – $1,500–$2,500
  • Installation labor – $1,000–$2,000
  • Oil cooler and miscellaneous – $300–$600

If the engine requires a forged rebuild for higher boost targets, add $2,500–$4,000. It is important to budget a buffer for unexpected issues (old hoses, leaks, etc.).

Reliability and Longevity

When correctly installed and tuned, a Greddy TD06SL2-20G IS300 can remain reliable for tens of thousands of miles. Key longevity factors include:

  • Oil Quality – Use a high-quality synthetic oil with proper viscosity (5W-30 or 10W-40) and change every 3,000–5,000 miles. The turbo requires clean oil to prevent coking.
  • Cool Down – After hard driving, let the engine idle for 60–90 seconds to circulate oil and cool the turbo bearings before shutdown. A turbo timer can automate this.
  • Boost Leaks – Check intercooler pipes and vacuum lines regularly. Leaks cause lean conditions and can destroy the engine.
  • Heat Management – Use a heat shield or turbo blanket to reduce radiant heat in the engine bay. Consider wrapping the downpipe to lower underhood temperatures.

At low-to-moderate boost (up to 12 psi), the stock 2JZ-GE block and heads are reliable if the tune is spot-on. Past 400 whp, a forged bottom end is strongly advised to prevent piston ring land failure.

Comparison with Other IS300 Turbo Options

The Greddy TD06SL2-20G is not the only turbo option for the IS300, but it occupies a sweet spot. Here is how it compares to common alternatives:

  • Stock IS300 Turbo (JDM Aristo/Soarer) – The smaller CT12 or CT15 turbo from a 2JZ-GTE can be adapted, but it runs out of steam around 280 whp. The Greddy offers far more headroom.
  • BorgWarner S200SX – A newer technology turbo with billet wheels and ball bearings. It spools faster and can support 450+ whp with better transient response, but costs more ($1,200+ just for the turbo).
  • Larger Greddy T67/T88 – These are for high-horsepower builds (600+ whp) but sacrifice low-end response. The TD06SL2-20G is more street-friendly.
  • Supercharger Kits – Sure or Vortech centrifugal superchargers deliver smooth linear power but produce less top-end than the TD06SL2-20G. They are easier to install but generally limited to 300–330 whp.

For most IS300 owners seeking a dramatic yet usable power gain, the Greddy TD06SL2-20G represents the best balance of cost, drivability, and peak output.

Conclusion

The Greddy TD06SL2-20G turbocharger is a proven upgrade for the Lexus IS300. With proper supporting modifications and a quality tune, owners can expect anywhere from 280 to 450 wheel horsepower depending on boost level and engine build. At low boost the car becomes a responsive, thrilling daily driver; at higher boost it can compete with dedicated sports cars. However, the power gains are only as reliable as the quality of the installation and tuning. Budget realistically, invest in a standalone ECU, and do not cut corners on fuel delivery. When done right, the TD06SL2-20G transforms the IS300 from a comfortable cruiser into a genuine performance machine that rewards the driver at every throttle input.

For further reading on the Greddy TD06SL2-20G and IS300 turbo setups, consider checking resources such as the Greddy official turbo page, the my.is IS300 forum for owner dyno threads, and tuning guides from reputable shops like Sound Performance. Always verify information against current best practices, as the aftermarket continues to evolve.