The AEM 21-686C 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 is designed, tuned and dyno-tested to fit specific Honda Civic 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 above the driver's side wheel well which is designed to reduce intake air temperature and increase horsepower. The intake tubing is constructed from mandrel-bent aluminum featuring a durable gunmetal gray powder coated finish. This air intake system was developed to accommodate the engine's factory emissions control devices including the mass air flow sensor and PCV hose. The cone 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 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 21-686C vehicle applications to determine the legal status for each vehicle.
Tuned and dyno-tested to improve acceleration and engine sound
Low restriction aluminum tubing
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
Estimated Horsepower Gain
4 HP @ 3800 RPM
Air Filter Color
Air Filter Material
Air Filter Outlet Shape
AEM Cold Air Intake System
Intake Pipe Color / Finish
Intake Pipe Material
CARB EO Number
Street Legal In All US States
TUV Approved (Europe)
10 lb (4.5 kg)
Product Box Height
12.25 in (311 mm)
Product Box Length
20.25 in (514 mm)
Product Box Width
12.25 in (311 mm)
Mounting Hardware Included
No cross references found for this part
Wrench, Extension, Flat Blade Screwdriver, Allen Wrench
Custom-engineered tubes deliver better airflow than you get with a stock intake. More air means better performance.
Using cotton gauze instead of typical folded paper, our filters increase airflow while providing excellent engine protection.
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