The AEM 21-478WR Performance Cold Air Intake System produces horsepower and torque gains by replacing your vehicle's restrictive factory air filter and air intake housing. This air intake system was designed, tuned and dyno-tested to fit specific Subaru WRX, WRX STI, Impreza WRX and Impreza WRX STI models. Air enters the system through an oversized AEM Dryflow synthetic washable air filter for outstanding air flow, filtration and performance. The air filter is located in the original air box space and is protected by a heat shield which is designed to reduce intake air temperature and increase horsepower. The intake tubing is constructed from mandrel-bent aluminum featuring a durable textured red powder coated finish. This air intake system was developed to accommodate the engine's factory emissions control devices including the mass air flow sensor. The cylinder shaped AEM Dryflow air filter is made from an oil-free, synthetic filter media that can be used for up to 100,000 miles before cleaning is needed (depending on driving conditions). The air intake system is easy to install with commonly available tools and it is backed by AEM's Lifetime Limited Warranty. Some AEM air intakes are not legal for sale or use in California and other states adopting California emission standards while others are 50 state legal. View the 21-478WR vehicle applications to determine the legal status for each vehicle.

• Utilizes washable, reusable, oil-free synthetic filter media that preserves airflow efficiency, traps harmful contaminants, and provides long-term value over disposable filters.
• AEM Lifetime Limited Warranty

This Part Fits:

AEM cold air intake systems are designed to increase horsepower and torque. The system includes an oversized AEM DRYFLOW synthetic washable air filter, engineered to provide outstanding airflow, filtration, and performance, and also features a mandrel-bent aluminum intake tube and high quality hardware. The oversized, conical filter design allows you to go up to 100,000 miles between filter services under normal highway driving conditions. A custom heat shield helps protect intake air from the high temperature of your engine bay, and the factory fresh air duct attaches to the heat shield. The entire system can typically be installed in less than 90 minutes.

• Utilizes washable, reusable, oil-free synthetic filter media that preserves airflow efficiency, traps harmful contaminants, and provides long-term value over disposable filters.

This Part Fits:

AEM Dryflow Universal Clamp-on Air Filters are washable synthetic air filters designed for a high-efficiency combination of air flow, filtration, and performance. AEM Dryflow filters use an innovative high performance oil-free filtration material that allows easy cleaning, durable service, and excellent filtration. This clamp-on universal air filter has a filter top for higher air flow capability making it great for everyday use.

• Supported by AEM’s trusted warranty, providing long-lasting confidence and reliability for enthusiasts who demand quality.
• Limited Lifetime Warranty

AEM Dryflow Universal Clamp-on Air Filters are washable synthetic air filters designed for a high-efficiency combination of air flow, filtration, and performance. AEM Dryflow filters use an innovative high performance oil-free filtration material that allows easy cleaning, durable service, and excellent filtration. This clamp-on universal air filter has a filter top for higher air flow capability making it great for everyday use.

• Supported by AEM’s trusted warranty, providing long-lasting confidence and reliability for enthusiasts who demand quality.
• Limited Lifetime Warranty

AEM Dryflow Universal Clamp-on Air Filters are washable synthetic air filters designed for a high-efficiency combination of air flow, filtration, and performance. AEM Dryflow filters use an innovative high performance oil-free filtration material that allows easy cleaning, durable service, and excellent filtration. This clamp-on universal air filter has a filter top for higher air flow capability making it great for everyday use.

• Supported by AEM’s trusted warranty, providing long-lasting confidence and reliability for enthusiasts who demand quality.
• Limited Lifetime Warranty

AEM Dryflow Universal Clamp-on Air Filters are washable synthetic air filters designed for a high-efficiency combination of air flow, filtration, and performance. AEM Dryflow filters use an innovative high performance oil-free filtration material that allows easy cleaning, durable service, and excellent filtration. This clamp-on universal air filter has a filter top for higher air flow capability making it great for everyday use.

• Supported by AEM’s trusted warranty, providing long-lasting confidence and reliability for enthusiasts who demand quality.
• Limited Lifetime Warranty

AEM Dryflow Air Filters were developed in collaboration with K&N, the inventor of High Flow Air Filters. We adopted some of the best elements of cotton air filters into a new generation synthetic Dryflow Air filter. The three-dimensional filtering medium uses both depth loading and structural screen wire to enhance airflow capabilities and make the filter incredibly easy to clean. The result is a true performance air filter that does not require oiling, carries a lifetime limited warranty and is capable of increasing horsepower and torque.

• Supported by AEM’s trusted warranty, providing long-lasting confidence and reliability for enthusiasts who demand quality.
• Lifetime Limited Warranty

AEM Dryflow Universal Clamp-on Air Filters are washable synthetic air filters designed for a high-efficiency combination of air flow, filtration, and performance. AEM Dryflow filters use an innovative high performance oil-free filtration material that allows easy cleaning, durable service, and excellent filtration. This clamp-on universal air filter has a filter top for higher air flow capability making it great for everyday use.

• Supported by AEM’s trusted warranty, providing long-lasting confidence and reliability for enthusiasts who demand quality.
• Limited Lifetime Warranty

AEM Dryflow Universal Clamp-on Air Filters are washable synthetic air filters designed for a high-efficiency combination of air flow, filtration, and performance. AEM Dryflow filters use an innovative high performance oil-free filtration material that allows easy cleaning, durable service, and excellent filtration. This clamp-on universal air filter has a filter top for higher air flow capability making it great for everyday use.

• Supported by AEM’s trusted warranty, providing long-lasting confidence and reliability for enthusiasts who demand quality.
• Limited Lifetime Warranty

AEM Dryflow Universal Clamp-on Air Filters are washable synthetic air filters designed for a high-efficiency combination of air flow, filtration, and performance. AEM Dryflow filters use an innovative high performance oil-free filtration material that allows easy cleaning, durable service, and excellent filtration. This clamp-on universal air filter has a filter top for higher air flow capability making it great for everyday use.

• Supported by AEM’s trusted warranty, providing long-lasting confidence and reliability for enthusiasts who demand quality.
• Limited Lifetime Warranty

AEM Dryflow Universal Clamp-on Air Filters are washable synthetic air filters designed for a high-efficiency combination of air flow, filtration, and performance. AEM Dryflow filters use an innovative high performance oil-free filtration material that allows easy cleaning, durable service, and excellent filtration. This clamp-on universal air filter has a filter top for higher air flow capability making it great for everyday use.

• Supported by AEM’s trusted warranty, providing long-lasting confidence and reliability for enthusiasts who demand quality.
• Limited Lifetime Warranty

AEM Dryflow Universal Clamp-on Air Filters are washable synthetic air filters designed for a high-efficiency combination of air flow, filtration, and performance. AEM Dryflow filters use an innovative high performance oil-free filtration material that allows easy cleaning, durable service, and excellent filtration. This clamp-on universal air filter has a filter top for higher air flow capability making it great for everyday use.

• Supported by AEM’s trusted warranty, providing long-lasting confidence and reliability for enthusiasts who demand quality.
• Limited Lifetime Warranty

AEM Dryflow Universal Clamp-on Air Filters are washable synthetic air filters designed for a high-efficiency combination of air flow, filtration, and performance. AEM Dryflow filters use an innovative high performance oil-free filtration material that allows easy cleaning, durable service, and excellent filtration. This clamp-on universal air filter has a filter top for higher air flow capability making it great for everyday use.

• Supported by AEM’s trusted warranty, providing long-lasting confidence and reliability for enthusiasts who demand quality.
• Limited Lifetime Warranty

AEM Dryflow Universal Clamp-on Air Filters are washable synthetic air filters designed for a high-efficiency combination of air flow, filtration, and performance. AEM Dryflow filters use an innovative high performance oil-free filtration material that allows easy cleaning, durable service, and excellent filtration. This clamp-on universal air filter has a filter top for higher air flow capability making it great for everyday use.

• Supported by AEM’s trusted warranty, providing long-lasting confidence and reliability for enthusiasts who demand quality.
• Limited Lifetime Warranty

This Part Fits:

AEM Dryflow Universal Clamp-on Air Filters are washable synthetic air filters designed for a high-efficiency combination of air flow, filtration, and performance. AEM Dryflow filters use an innovative high performance oil-free filtration material that allows easy cleaning, durable service, and excellent filtration. This clamp-on universal air filter has a filter top for higher air flow capability making it great for everyday use.

• Supported by AEM’s trusted warranty, providing long-lasting confidence and reliability for enthusiasts who demand quality.
• Limited Lifetime Warranty

AEM Dryflow Universal Clamp-on Air Filters are washable synthetic air filters designed for a high-efficiency combination of air flow, filtration, and performance. AEM Dryflow filters use an innovative high performance oil-free filtration material that allows easy cleaning, durable service, and excellent filtration. This clamp-on universal air filter has a filter top for higher air flow capability making it great for everyday use.

• Supported by AEM’s trusted warranty, providing long-lasting confidence and reliability for enthusiasts who demand quality.
• Lifetime Limited Warranty

AEM Dryflow Universal Clamp-on Air Filters are washable synthetic air filters designed for a high-efficiency combination of air flow, filtration, and performance. AEM Dryflow filters use an innovative high performance oil-free filtration material that allows easy cleaning, durable service, and excellent filtration. This clamp-on universal air filter has a filter top for higher air flow capability making it great for everyday use.

• Supported by AEM’s trusted warranty, providing long-lasting confidence and reliability for enthusiasts who demand quality.
• Lifetime Limited Warranty

AEM Dryflow Universal Clamp-on Air Filters are washable synthetic air filters designed for a high-efficiency combination of air flow, filtration, and performance. AEM Dryflow filters use an innovative high performance oil-free filtration material that allows easy cleaning, durable service, and excellent filtration. This clamp-on universal air filter has a filter top for higher air flow capability making it great for everyday use.

• Supported by AEM’s trusted warranty, providing long-lasting confidence and reliability for enthusiasts who demand quality.
• Limited Lifetime Warranty

AEM Dryflow Universal Clamp-on Air Filters are washable synthetic air filters designed for a high-efficiency combination of air flow, filtration, and performance. AEM Dryflow filters use an innovative high performance oil-free filtration material that allows easy cleaning, durable service, and excellent filtration. This clamp-on universal air filter has a filter top for higher air flow capability making it great for everyday use.

• Supported by AEM’s trusted warranty, providing long-lasting confidence and reliability for enthusiasts who demand quality.
• Limited Lifetime Warranty

AEM Dryflow Universal Clamp-on Air Filters are washable synthetic air filters designed for a high-efficiency combination of air flow, filtration, and performance. AEM Dryflow filters use an innovative high performance oil-free filtration material that allows easy cleaning, durable service, and excellent filtration. This clamp-on universal air filter has a filter top for higher air flow capability making it great for everyday use.

• Supported by AEM’s trusted warranty, providing long-lasting confidence and reliability for enthusiasts who demand quality.
• Lifetime Reusable Element

AEM Dryflow Universal Clamp-on Air Filters are washable synthetic air filters designed for a high-efficiency combination of air flow, filtration, and performance. AEM Dryflow filters use an innovative high performance oil-free filtration material that allows easy cleaning, durable service, and excellent filtration. This clamp-on universal air filter has a filter top for higher air flow capability making it great for everyday use.

• Supported by AEM’s trusted warranty, providing long-lasting confidence and reliability for enthusiasts who demand quality.
• Limited Lifetime Warranty

AEM Dryflow Universal Clamp-on Air Filters are washable synthetic air filters designed for a high-efficiency combination of air flow, filtration, and performance. AEM Dryflow filters use an innovative high performance oil-free filtration material that allows easy cleaning, durable service, and excellent filtration. This clamp-on universal air filter has a filter top for higher air flow capability making it great for everyday use.

• Supported by AEM’s trusted warranty, providing long-lasting confidence and reliability for enthusiasts who demand quality.
• Limited Lifetime Warranty

AEM Dryflow Air Filters were developed in collaboration with K&N, the inventor of High Flow Air Filters. We adopted some of the best elements of cotton air filters into a new generation synthetic Dryflow Air filter. The three-dimensional filtering medium uses both depth loading and structural screen wire to enhance airflow capabilities and make the filter incredibly easy to clean. The result is a true performance air filter that does not require oiling, carries a lifetime limited warranty and is capable of increasing horsepower and torque.

• Supported by AEM’s trusted warranty, providing long-lasting confidence and reliability for enthusiasts who demand quality.
• Limited Lifetime Warranty

AEM Dryflow Universal Clamp-on Air Filters are washable synthetic air filters designed for a high-efficiency combination of air flow, filtration, and performance. AEM Dryflow filters use an innovative high performance oil-free filtration material that allows easy cleaning, durable service, and excellent filtration. This clamp-on universal air filter has a filter top for higher air flow capability making it great for everyday use.

• Supported by AEM’s trusted warranty, providing long-lasting confidence and reliability for enthusiasts who demand quality.
• Limited Lifetime Warranty

AEM Dryflow Universal Clamp-on Air Filters are washable synthetic air filters designed for a high-efficiency combination of air flow, filtration, and performance. AEM Dryflow filters use an innovative high performance oil-free filtration material that allows easy cleaning, durable service, and excellent filtration. This clamp-on universal air filter has a filter top for higher air flow capability making it great for everyday use.

• Supported by AEM’s trusted warranty, providing long-lasting confidence and reliability for enthusiasts who demand quality.
• Limited Lifetime Warranty

AEM Dryflow Universal Clamp-on Air Filters are washable synthetic air filters designed for a high-efficiency combination of air flow, filtration, and performance. AEM Dryflow filters use an innovative high performance oil-free filtration material that allows easy cleaning, durable service, and excellent filtration. This clamp-on universal air filter has a filter top for higher air flow capability making it great for everyday use.

• Supported by AEM’s trusted warranty, providing long-lasting confidence and reliability for enthusiasts who demand quality.
• Lifetime Reusable Element

AEM Dryflow Air Filters were developed in collaboration with K&N, the inventor of High Flow Air Filters. We adopted some of the best elements of cotton air filters into a new generation synthetic Dryflow Air filter. The three-dimensional filtering medium uses both depth loading and structural screen wire to enhance airflow capabilities and make the filter incredibly easy to clean. The result is a true performance air filter that does not require oiling, carries a lifetime limited warranty and is capable of increasing horsepower and torque.

• Supported by AEM’s trusted warranty, providing long-lasting confidence and reliability for enthusiasts who demand quality.
• Limited Lifetime Warranty

AEM Dryflow Universal Clamp-on Air Filters are washable synthetic air filters designed for a high-efficiency combination of air flow, filtration, and performance. AEM Dryflow filters use an innovative high performance oil-free filtration material that allows easy cleaning, durable service, and excellent filtration. This clamp-on universal air filter has a filter top for higher air flow capability making it great for everyday use.

• Supported by AEM’s trusted warranty, providing long-lasting confidence and reliability for enthusiasts who demand quality.
• Limited Lifetime Warranty

AEM Dryflow Air Filters were developed in collaboration with K&N, the inventor of High Flow Air Filters. We adopted some of the best elements of cotton air filters into a new generation synthetic Dryflow Air filter. The three-dimensional filtering medium uses both depth loading and structural screen wire to enhance airflow capabilities and make the filter incredibly easy to clean. The result is a true performance air filter that does not require oiling, carries a lifetime limited warranty and is capable of increasing horsepower and torque.

• Supported by AEM’s trusted warranty, providing long-lasting confidence and reliability for enthusiasts who demand quality.
• Limited Lifetime Warranty

AEM Dryflow Universal Clamp-on Air Filters are washable synthetic air filters designed for a high-efficiency combination of air flow, filtration, and performance. AEM Dryflow filters use an innovative high performance oil-free filtration material that allows easy cleaning, durable service, and excellent filtration. This clamp-on universal air filter has a filter top for higher air flow capability making it great for everyday use.

• Supported by AEM’s trusted warranty, providing long-lasting confidence and reliability for enthusiasts who demand quality.
• Lifetime Reusable Element