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K&N® Introduces 69-8009TWR Air Intake System for 2018 Subaru WRX STI 2.5L

Designed to be compatible with 2018 Subaru WRX STI 2.5L models, the K&N® 69-8009TWR Air Intake System offers a guaranteed increase in horsepower and torque for WRX owners.

2018 Subaru WRX STI in World Rally Blue, courtesy of Subaru of America

2018 Subaru WRX STI in World Rally Blue, courtesy of Subaru of America

The WRX is a rally-car inspired vehicle, known for precise handling in an all-weather package. The 2018 Subaru WRX STI is a solid mixture of performance and daily-driver capability—full of conveniences and safety features including lane departure warning, automatic emergency breaking, and blind-spot monitoring—while also delivering a substantial 305-horsepower and 290 lb-ft of torque from a 2.5-liter turbocharged 4-cylinder engine.

The standard 2.5-liter engine offers quite a bit of power—but for those looking for an extra boost in horsepower, the K&N® 69-8009TWR Air Intake System can reduce unnecessary air turbulence that may slow the volume of airflow reaching the engine.

The 69-8009TWR complete with powder-coated intake tube

The 69-8009TWR complete with powder-coated intake tube

The K&N® 69-8009TWR air intake system is a free-flowing, mandrel-bent aluminum tube air induction system (powder-coated in red) designed to replace the factory air filter and air intake components. K&N® powder-coated aluminum intake tubes are meticulously designed to be aerodynamic, and when paired with the included High-Flow Air Filter™ can provide dramatic increases in airflow. The oversized conical air filter allows for up to 100,000 miles between cleanings under normal highway driving conditions, and is washable, durable, and reusable. The filter is placed in the front wheel well opening to allow for as much fresh air as possible and protect the filter from high engine temperatures. When your filter is due for a cleaning, the K&N Recharger® Kit (99-5000) contains everything you’ll need to quickly and easily wash away contaminants and restore your filter’s performance.

The 69-8009TWR system also features a custom powder-coated aluminum heat shield, protecting the air filter and intake air from the high temperatures radiating from the engine. The heat shield installs onto the lower factory air box, retaining the fresh air inlet. The air intake tube funnels airflow directly into the engine’s throttle body for a guaranteed increase in horsepower and torque.

The 69-8009TWR after installation

The 69-8009TWR after installation

Installation of your new air intake system can typically be completed in 90 minutes or less, as the kit utilizes existing factory mounting points, incorporates the factory mass air sensor, and requires only basic hand tools. Since the cold air intake system allows for the removal of unnecessary stock air intake components, your engine bay will be left with a cleaner appearance after installation.

The results are verifiable and impressive—on a chassis dynamometer, a 2018 Subaru WRX STI 2.5L with the stock air intake was recorded at 248.0-hp at 5,999rpm, and after installation of the 69-8009TWR the same vehicle was recorded at 273.2-hp at 5,999rpm—an estimated increase of 25.2-hp. The torque was also improved from 172.5 lb-ft on the stock air intake to 182.9 lb-ft with the 69-8009TWR —a total estimated increase in torque of 11.4 lb-ft at 2,907rpm. You can buy with confidence under the 10-Year/Million Mile Limited Warranty—and the knowledge that you’re guaranteed an increase in horsepower and torque.

The 69-8009TWR is designed for use in the following vehicles:

2018 Subaru WRX STI 2.5L H4 Fuel Injection: All Models


Will using a K&N® replacement air intake system void my factory warranty?

No. In the United States, in order for the manufacturer of a warranted product to void or deny warranty coverage of a repair due to the use of an aftermarket part, the manufacturer must provide proof that the aftermarket part is the cause of the necessary repair. These rights are protected under the Consumer Products Warranty Act of 1975 (also referred to as the Magnuson-Moss Warranty Act).

Are K&N® performance air intake systems or RK-series custom air cleaner assemblies emissions legal in the U.S.?

Performance intake systems are legal for street use in most areas of the United States.

In California, and in specific regions which have adopted California air quality regulations, only CARB-exempt performance intakes are legal for street use.

Check the K&N catalog or website for vehicle applications and specific CARB status for each vehicle and air intake.

Can a K&N® product cause my Check Engine Light or Service Light to come on?

It is possible that the Check Engine Light may come on after installing a K&N air filter or performance intake system. This does not necessarily mean that there is something wrong with your air filter or intake; sometimes, the higher air flow and lower restriction provided by the K&N product will uncover an existing mechanical or electronic issue with your vehicle. In rare cases, you may have a K&N product which was manufactured outside of its design tolerances, causing sensors in your vehicle to read data outside of their normal expected values. In either case, the K&N Warranty Department can work with you to narrow down the cause of the Check Engine Light and correct the issue.

How much horsepower does a K&N® cold air intake add?

Dynamometer tests indicating horsepower and torque increases over the OEM intake system will appear on the "Product Details" page for each of our performance intake systems.

What does a cold air intake do for a car?

Cold air intakes allow for increased airflow to your engine, which results in an increase in torque and acceleration for your vehicle.

Can cold air intakes improve gas mileage?

In theory, a cold air intake could increase the gas mileage of your vehicle due to improved airflow which allows the engine to run more efficiently and require less fuel. However, K&N does not make any guarantees in terms of increased gas mileage with the use of our filters or intakes.

*Some intake systems are not legal for sale or use on any pollution controlled motor vehicle in California or states adopting California emission procedures. See for CARB status on each part for a specific vehicle.

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