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Part:   21-735WR

AEM 21-735WR Cold Air Intake

AEM Cold Air Intake System
Rating Star 1 Rating Star 2 Rating Star 3 Rating Star 4 Rating Star 5   5.0
  • Increased horsepower
  • Tuned and dyno-tested to improve acceleration and engine sound
  • Low restriction aluminum tubing
  • Easy to install using commonly available tools
  • Air filter lasts up to 100,000 miles before cleaning is required (depending on driving conditions)
  • Washable and reusable oil-free filter media
  • AEM Lifetime Limited Warranty

The AEM 21-735WR fits some Subaru Impreza WRX STi, and Subaru WRX STI models. See vehicle applications for details.
The AEM 21-735WR 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 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 tapered 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 21-735WR vehicle applications to determine the legal status for each vehicle.

[More Information on AEM Cold Air Intake Systems]
Specifications AEM 21-735WR Product Specifications
Air Filter ColorRed
Air Filter Height9 in (229 mm)
Air Filter MaterialNon-woven Synthetic
Air Filter Outlet ShapeRound
CARB EO NumberD-670-18
Clamp MaterialStainless Steel
Clamp StyleRegular
Clamps Included3
Intake Pipe Color / FinishWrinkle Red
Intake Pipe MaterialAluminum
Product Box Height12.25 in (311 mm)
Product Box Length20.25 in (514 mm)
Product Box Width12.25 in (311 mm)
Product StyleAEM Cold Air Intake System
Replacement Filter21-2029D
Street Legal In All US StatesSee Application Link Above
TUV Approved (Europe)No
Weight8.9 lb (4 kg)
Accessories / Related Items Accessories / Related Items
Reviews Product Reviews

Scott Jefferies from Sussex, United Kingdom
September 5, 2015 - Part 21-735WR
Just fitted to my UK spec 2015 STi - Very happy with this product, very easy to fit in less than 40 minutes with clear instructions. Sounds fantastic and the car feels noticeably faster with better throttle response in SportNo. setting. Love the flutter noise when you change gear too. Highly recommended modification.
Anthony Chavez from Colorado
April 25, 2015 - Part 21-735WR
Easy install, sounds great, and definitely felt that my engine was breathing better with the CAI. I highly recommend!
Dee Childs from Victorville, California
November 21, 2014 - Part 21-735WR
Excellent Product!
Aaron from Virginia
November 11, 2014 - Part 21-735WR
Great Product! Installed this on my 2015 Subaru STi. Sounds amazing, way better than the sound generator on the stock intake. Intake Air Temp, matched OEM intake levels of ambient temperature at idle. Power was improved on the top end, as I hit 20psi via sport sharp. I am tuned for the AEM intake via a Visconti (ECUTek) 93 Octane Stage 1 + AEM flash though so I can not comment on how this will preform on the stock ECU flash. Thanks AEM!!