Lexus IS300 Turbo Kit Upgrade Guide

While the IS300 unquestionably has some other standout features in the performance department, the real selling point was the 2JZ-GE powerplant that put out 217 horsepower and 218 lb-ft of torque in factory form. That engine should be immediately familiar for its use in the N/A MK4 Toyota Supra, where it became famous for its unparalleled strength and power potential. Of course, 218 naturally aspirated horsepower isn’t exactly anything to write home about. However, the Lexus IS300 truly comes alive when performance modifications come into play. 

The 2JZ-GE is one of the most capable engines under the sun. That’s where forced induction comes into play. Slapping a turbocharger onto your IS300 is one of the best options to add around 150-200 horsepower. With that being said, installing a turbo is a costly and research-intensive process. If you are looking into what it takes to turbocharge your IS300 and discover some turbo kit options, keep reading.

Engine Power Limits

When thinking about turbocharging your Lexus IS300, the first inevitable question is how much power you’ll be able to squeeze out of the 2JZ-GE. The 2JZ’s cast-iron block and aluminum head are capable of withstanding a remarkable amount of abuse. With that being said, the 2JZ-GE found in the IS300 is slightly different than the turbocharged 2JZ-GTE found in the Supra, and some of those differences do play a part in the maximum horsepower figures of an otherwise stock engine.

350-400hp is about the limit for reliability on stock internals. The primary limitation on an IS300 making extreme power is its higher compression ratio, as adding an excess of pressure to already highly pressurized cylinders is a recipe for issues. 7-8 PSI of boost is the higher end of the ceiling without considering rods and a head gasket in addition to other supporting mods. 

Generally speaking, an IS300 with a solid turbo kit and basic supporting mods can reliably run 350-400 hp without too much effort and without draining the bank. It’s when numbers reach 450 and beyond that, additional, and costly, steps need to be taken to prevent the engine or transmission from giving up. 

Turbo Upgrade Considerations

Before ordering the first IS300 turbo kit that jumps out at you, it is important to understand what components come in the kit and understand how they will all come together in the end. Not all turbos are created equally, and size and build quality should be a big factor in your decision. Beyond the turbo itself, you’ll also need to think about supporting modifications and a quality tune. Since the first-gen’s are an aging car at this point, you’ll have to consider the condition of your engine as well. Just because the 2JZ-GE is a tank of an engine doesn’t mean that it is fail-proof. 

Turbo Sizing

Turbo sizing determines both how much horsepower can be generated from forced induction as well as how that power is delivered. There is quite a discrepancy in the amount of power a T3 and T70 size turbo, for instance, is able to produce. While a larger turbo might be able to produce more power and run higher boost levels, there’s more to consider.

T3 and T4 turbos are the most common sizes to be fitted to the IS300. Most of the aftermarket off-the-shelf turbo kits utilize a T4 flange turbo. T4 turbos are ideal for applications in the 300-350 horsepower range. While T4 turbos are larger than T3s, their spool time is relatively low which makes them a good option for a daily-driven setup. 

While it is true that you’ll unquestionably be able to squeeze more power out of a massive T70 turbocharger, the boost characteristics won’t be ideal for a street-able turbo IS300. With a T70 or similarly sized turbo, boost lag will be immense in the lower rev range. Since the turbine will take longer to spool, you’ll have little response low in the rev range which some people cannot stand. However, if you are willing to trade low-end performance for a massive horsepower figure, a larger turbo is the way to go. A T70 turbo on an IS300 can push horsepower numbers beyond 450. Of course, you’ll have to upgrade nearly all of your 2JZ-GE internals, fuel system, and other supporting mods to do so. 

Fuel System Upgrades

One of the most important supporting systems when it comes to turbocharging a 2JZ-GE is the fuel system. With the increased airflow from applying a turbo to the equation, your fuel system will need to compensate. While the stock fuel system will work with a turbo application up to a point, turbo IS300s running more than 300 horsepower will need some fueling upgrades. 

Perhaps the most important upgrade that you’ll need to think about is a stronger fuel pump. The most common fuel pump upgrade is the Walbro 225, which can support up to 500 horsepower to the crank. With an upgraded fuel pump, an upgraded fuel pressure regulator might also be necessary depending on how crazy you intend your turbo build to be. 

It is generally concluded that stock IS300 injectors aren’t the best option as far as forced induction is concerned. The stock 260-290cc injectors are only good for around that amount of horsepower. As a general rule, 1cc equals around 1rwhp. So, if you are looking for power in the 350-400 range, larger injectors are a necessity. 440cc injectors are extremely popular and a great option.

Engine Management System and Tuning

When it comes to turbocharging an IS300, one of the most important aspects is tuning it properly. Unfortunately, it is a notoriously difficult car to tune properly. The factory ECU is finicky in terms of what it is able to handle with a piggyback tune. Piggyback options like an S-AFC, are possible to use for turbo applications, but it generally isn’t worth the headache.

The other alternative is swapping in an aftermarket ECU, which is the much more common option. With an aftermarket ECU, you’ll also need a PNP wiring harness adapter. That will allow the new ECU to communicate with the auxiliary systems. Some PNP adapters allow the new ECU to run in parallel with the factory IS300 ECU. This is necessary on cars with automatic transmissions, as automatics have to be managed by the stock ECU. 

The AEM Infinity 506 is the most popular aftermarket IS300 ECU on the market. It allows you to make the necessary adjustments to your air/fuel mixture and has engine protection strategies built in. In addition, you’ll be able to make changes to your drive-by-wire system, cam timing, boost control, traction control, and essentially anything else that you can think of. As such, you’ll need to consult a professional that can make these adjustments to best suit your turbo setup’s needs. Generally speaking, a quality dyno tune can be an expensive endeavor. However, it is entirely necessary to get the most out of your IS300 setup.

Lexus IS300 Turbo Kits

Alright. Finally onto the more exciting part. Once you’ve determined your budget and goals it’s time to choose a turbo kit. This list is by no means exhaustive, and best is subjective. As the IS300 is over 20 years old at this point, turbo kits are getting harder to find. Most of the popular kits from 10+ years ago have since been discontinued. However, there are still a few solid contenders out there that shine in different ways. As such, these are a few kits that we believe provide a great balance of price, quality, and performance.

1) CXRacing Turbo Kit

Price: $2,332.81

Turbo: T4 GT35 Turbo with or without ceramic dual ball bearing

The CXRacing kit is one of the most comprehensive IS300 turbo kits on the market. Unlike many other kits for the 2JZ-GE-powered IS300, the CX kit comes with pretty much all of the turbo hardware including a manifold, downpipe, turbo and intercooler. It truly is the full package. 

Some other IS300 turbo kits require additional modifications to stock hardware for fitment reasons. With that being said, the CXRacing kit keeps the stock ABS unit in place. The turbo is also mounted in a backward configuration for more clearance. The provided GT35 turbo falls in the T4 class and is rated for between 300-500 horsepower. With a 0.86 AR housing and 4” inlet, the GT35 is a turbo that spools fast for low-end power.

The CXRacing IS300 turbo kit also comes with a direct fit front mount intercooler. The included intercooler is designed to provide the maximum amount of cooling capacity. It can also be installed without the need to make any modifications to the front bumper. 

This kit is the perfect option for someone looking to boost their 2JZ-GE with the maximum amount of ease. This kit removes the need to scour the internet to build a piecemeal turbo setup as all of the necessary hardware is ready to go. At $2.3k, you aren’t likely to find another all-inclusive kit that provides the quality that the CXRacing kit provides. 

2) DriftMotion Billet T04 Turbo Kit

Price: $1,999.00

Turbo: 67mm Billet Turbo with Garrett internals / Area over Radius available from 0.58 – 0.84 AR

The DriftMotion IS300 turbo kit is a good option for those that already have a downpipe and intercooler solution. In terms of quality, it is hard to beat the turbo provided with the DriftMotion kit. The T04 turbo comes with a ceramic coated exhaust housing and an anti-surge compressor housing for maximum strength. The turbo is available with either a standard aluminum cast compressor wheel or billet 11-blade wheel for an additional cost. The billet wheel can withstand more abuse and higher pressure, making it a good option for those with high-horsepower 2JZ aspirations.

In addition to the compressor wheel, the DriftMotion turbo’s area over radius can also be customized for your preference. A smaller AR will move the power and torque curve lower in the rev range, with the opposite being true for larger ARs. Changing turbo AR also affects how the turbo spools, with smaller AR figure turbos spooling faster than turbos with a higher AR. As far as how that affects the characteristics of the 2JZ-GE in your IS300, it all depends on where you want the boost to come on. 

As stated previously, the DriftMotion kit does not come with an IS300 turbo downpipe or intercooler. Those are components that you’ll have to source from elsewhere. That isn’t necessarily a bad thing, as most people have specific downpipe and intercooler preferences anyway. To install the kit, the factory ABS unit needs to be relocated.

3) XS-Power 2001-2005 Turbo Kit

Price: $1,350.00

Turbo: 67mm T4 Turbo 

Turbo kits for any car can get mighty expensive and there’s really no ceiling as to what you can spend. However, that doesn’t have to be the case, as proven by the XS-Power IS300 turbo kit. While it might not be the most premium kit on the market, there are a number of positive reports that the XS-Power kit will get the job done reliably. Especially if run at low to moderate boost levels. 

For just over $1,300, it’s hard to believe that there is a complete IS300 turbo kit for that price range. But, that’s exactly what the XS-Power kit is. It comes with virtually everything you’ll need hardware-wise. That includes the turbo, manifold, wastegate, FMIC, piping, gaskets, chargepipe, and downpipe. While most of the necessary parts are included, some modification is required for the kit to work with an IS300. For instance, the intercooler piping needs to be cut to fit. The front radiator support will also need to be slightly modified for the massive front mount intercooler to fit. 

With the factory 2JZ-GE head gasket, 350 horsepower is a reasonable figure to expect. That is, without getting too heavily involved with other supporting modifications. 8 psi on the turbo is the sweet spot for both power and reliability on this setup.

Summary

There is a very important element standing between the Lexus IS300 and its full potential: a turbo. While the factory 2JZ-GE engine is very capable, it can be stretched far beyond its stock form. Since the 2JZ-GE is such a strong engine, it is an ideal candidate for forced induction.

Turbocharging your IS300 is the best way to see massive performance gains. Turbo upgrades can be a very expensive venture depending on your horsepower goal. However, a “moderate” 75-100 horsepower increase can be achieved without draining your bank account. It isn’t until you reach the internal limits of the 2JZ-GE that things get truly expensive.

When turbocharging an IS300, there are quite a few considerations that you’ll need to take into account. Some of the main ones include turbo sizing, fueling requirements, engine management, and tuning. All of these considerations will determine how much power your turbo is capable of making and its reliability.

If you enjoyed this article, also check out our Best IS300 Performance Mods article! As always, safe driving!