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Lexus IS: Supercharging, Turbocharging and Nitrous Modifications

This article covers the ways to most effectively add power to your Lexus IS.

By Pizzaman711 - January 6, 2015

This article applies to the Lexus IS 250 and IS 350 (2005-2014).

Superchargers, turbochargers and nitrous are the only options for true power gains on the Lexus IS. Unfortunately, adding power is not cheap and will definitely void any form of a warranty on the vehicle's powertrain. Modifying a Lexus is especially difficult because the engine control module is locked down to tuners. Typically, a modified Lexus IS gains around 40-60hp at the rear wheels. The car will have more pep, but you won't be able to build it into a monster race car without extensive rebuilding.

Pro Tip

The Lexus IS 250 and IS 350 are notoriously bad platforms for aspiring tuners. However, the Lexus IS 300 is a stout and easily tunable performance vehicle. Turbocharging kits, supercharging kits, nitrous, engine swaps and more are readily available at a considerably lower price. Alternatively, if money is no object, the Lexus IS F is also a great option.

Superchargers

Superchargers function by forcing more air into the motor. This extra air allows the motor to burn more fuel, thus creating more power. Unlike turbochargers, superchargers are driven by the belt off of the engine's crankshaft, so that's spinning in unison with the engine's. Boost is built by pressurizing the air coming into the supercharger. The faster the impeller spins, the more boost it builds.

Figure 1. A typical supercharger.

Arma Speed

DIY Cost – $7,480

Professional Cost – $8,500-$9,500

Skill Level – Difficult

Arma makes a well-built supercharger kit, which claims to give gains of around 100hp before driveline loss. This kit is only made for the IS 250 which makes it somewhat unreasonable to purchase with the price. The huge price tag attached is more than what you'd spend to trade in your 250 and upgrade to a 350, which will make more power stock than your 250 will supercharged. But those who prefer to keep the 250, because of the manual transmission or any other reason, definitely won't be disappointed with this kit.

LMS

DIY Cost– $5,000

Professional Cost – $6,000-$7,000

Skill Level – Difficult

The LMS kit is a well-built supercharger for the IS 350. Gains are around 100hp at the crank with around 40-60 at the rear wheels being seen during dyno testing. LMS' kit is one of the few kits available for the IS 350. While you can't customize the tune to run higher boost pressures, this kit offers the most HP per dollar on any mod for the IS. Installation of this kit is straightforward. It should take a day at most for the mechanically inclined.

Custom

DIY Cost – $3,000-$10,000 and up

Professional Cost – $1,000-$2,000 plus parts

Skill Level – Difficult

Custom setups open all new options for how to put your system together. Depending on what you are going for, it can save you money or end up costing you a lot more. A custom supercharger setup will require brackets for mounting, custom accessory belts, supporting hardware and several other considerations. It is suggested doing research prior to purchasing components. Keep in mind that the Lexus' computer is hard to tune. A custom supercharged Lexus needs components that work well together and won't damage the motor by creating too much boost. A custom build can be done using the highest quality parts available or other people's leftover parts. It's totally up to you.

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Turbochargers

Similar to superchargers, turbochargers use an impeller or turbine to force more air into the motor. The difference is that turbochargers use the exhaust gas to spin the turbine whereas the supercharger is driven by the crankshaft.

Figure 2. A typical turbocharger.

Custom

DIY Cost – $4,000-$10,000

Professional Cost – $1,000-$2,000 plus parts

Skill Level – Difficult

There are no full production turbocharger kits on the market for the 3IS's currently; however, there are a lot of similar kits you can pull parts from. The biggest problem you'll have with a turbo on these motors is that, with the high compression ratio, you can only run a low amount of boost. Turbos are popular because they can make high-boost amounts, easily translating to huge gains. In a low-boost scenario like that of the IS, they lose a lot of appeal. This is due to turbochargers affecting a smaller region of the powerband, as well as requiring extra maintenance such as oiling them.

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Nitrous

Nitrous has two main effects that improve performance, so it gives you that quick burst of energy. The first is that when nitrous (N2O) gets warm enough, like when being sprayed into a motor, it splits into nitrogen and oxygen, thus providing more oxygen for the motor. The second effect is that when it burns off it provides a cooling effect to the air, which causes the air to become more dense, which also provides the motor with more oxygen.

Figure 3. Typical nitrous setup.

Custom

DIY Cost – $500-$1,500

Professional Cost– $500-$1,000 plus parts

Skill Level– Difficult

Nitrous can give you a short boost of power that is normally controlled via a window switch. Window switches allow the driver to set the RPM range and the gear for the nitrous to start and stop spraying. The result is on-demand power similar to the kind provided by a supercharger. The downside to nitrous is that too large of a shot (the amount sprayed) can easily damage the motor. Getting the bottle filled can also quickly add up depending on driving style. The average nitrous bottle is around 10-15lb and the cost to fill is around $4-$10 per pound, depending on location. There is no Lexus IS specific kit off the shelf for nitrous; however, most kits are made to be universal. Adapting a nitrous system to any Lexus is the same as it is in any other car.

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