AEM's Performance Cold Air Intake Systems are tuned and dyno-tested to give your engine more power and acceleration by replacing the restrictive factory air filter, air intake tubing and air box assembly.
The AEM 21-681C 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 Audi A4 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 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. 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).
- Precision-tuned and dyno-validated to enhance throttle response, sharpen acceleration, and improve overall engine efficiency, helping maximize horsepower and drivability.
- Creates a deeper, more aggressive induction tone that highlights the intake system’s improved airflow.
- Features low-restriction intake tubing that increases air velocity and high-volume airflow for maximum performance gains.
- Equipped with a long-life, high-capacity air filter capable of up to 100,000 miles before servicing (depending on driving conditions), reducing maintenance while maintaining strong, clean airflow.
- Utilizes washable, reusable, oil-free synthetic filter media that preserves airflow efficiency, traps harmful contaminants, and provides long-term value over disposable filters.
Application Summary:
| Year |
Make/Model |
| 2002-2006 |
Cadillac Escalade |
| 2003-2006 |
Cadillac Escalade ESV |
| 2002-2006 |
Cadillac Escalade EXT |
| 2002-2006 |
Chevrolet Avalanche 1500 |
| 1999-2006 |
Chevrolet Silverado 1500 |
| 2007 |
Chevrolet Silverado 1500 Classic |
| 2001-2003 |
Chevrolet Silverado 1500 HD |
| 2005-2006 |
Chevrolet Silverado 1500 HD |
| 2007 |
Chevrolet Silverado 1500 HD Classic |
| 1999-2002 |
Chevrolet Silverado 2500 |
| 2004 |
Chevrolet Silverado 2500 |
| 2001-2006 |
Chevrolet Silverado 2500 HD |
| 2007 |
Chevrolet Silverado 2500 HD Classic |
| 2001-2006 |
Chevrolet Silverado 3500 |
| 2000-2006 |
Chevrolet Suburban 1500 |
| 2000-2006 |
Chevrolet Suburban 2500 |
| 2000-2006 |
Chevrolet Tahoe |
| 1999-2006 |
GMC Sierra 1500 |
| 2007 |
GMC Sierra 1500 Classic |
| 2001-2003 |
GMC Sierra 1500 HD |
| 2005-2006 |
GMC Sierra 1500 HD |
| 2007 |
GMC Sierra 1500 HD Classic |
| 1999-2004 |
GMC Sierra 2500 |
| 2001-2006 |
GMC Sierra 2500 HD |
| 2007 |
GMC Sierra 2500 HD Classic |
| 2001-2006 |
GMC Sierra 3500 |
| 2007 |
GMC Sierra 3500 Classic |
| 2000-2006 |
GMC Yukon |
| 2001-2006 |
GMC Yukon XL 1500 |
| 2000-2006 |
GMC Yukon XL 2500 |
| Attributes |
| Air Box Included |
No |
| Air Filter Color |
Red |
| Air Filter Element Washable |
Yes |
| Air Filter Height |
8.125 in (206 mm) |
| Air Filter Large End Diameter |
7.5 in (191 mm) |
| Air Filter Material |
Non-woven Synthetic |
| Air Filter Oulet Length |
6.000 in. (152mm) |
| Air Filter Oulet Width |
6.000 in. (152mm) |
| Air Filter Outlet Length |
6 in (152 mm) |
| Air Filter Outlet Shape |
Round |
| Air Filter Outlet Width |
6 in (152 mm) |
| Air Filter Washable |
Yes |
| Alternate Part Number |
AEM-21-8000DC |
| ASIN |
B000N21KOK |
| California Proposition 65 |
WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov |
| CARB EO Number |
D-670-15 |
| Clamp Color |
Natural |
| Clamp Color/Finish |
Natural |
| Clamp Material |
Steel |
| Clamp Quantity |
5 |
| Clamp Style |
Regular |
| Clamps Included |
5 |
| Country of Origin (Primary) |
US |
| Coupler Color |
Not Applicable |
| Coupler Color/Finish |
Black |
| Couplers Included |
1 |
| Emission Code |
Legal US |
| Estimated Horse Power Gain |
12.25 HP @ 4796 RPM |
| Estimated Horsepower Gain |
12.25 HP @ 4796 RPM |
| Filter Color |
Red |
| Filter Material |
Non-woven Synthetic |
| Harmonized Tariff Code (Schedule B) |
8421310000 |
| Hazardous Material Code |
N |
| Horse Power Increase |
12 HP |
| Intake Pipe Color |
Gunmetal Gray |
| Intake Pipe Color / Finish |
Gunmetal Gray |
| Intake Pipe Inlet Length |
28 in (711 mm) |
| Intake Pipe Inlet Shape |
Round |
| Intake Pipe Inlet Width |
4 in (102 mm) |
| Intake Pipe Material |
Aluminum |
| Intake Pipe Outlet Length |
28 in (711 mm) |
| Intake Pipe Outlet Shape |
Round |
| Intake Pipe Outlet Width |
4 in (102 mm) |
| Intake Pipe Ports |
All intake tube ports needed for the specified applications are included |
| Item Weight |
11.000 lbs. (5 kg) |
| Life Cycle Status Code |
Available to Order |
| Mass Air Flow Sensor Adapter Included |
No |
| Mass Air Flow Sensor Included |
Mass Air Flow Sensor Adapter Included When Required |
| Mounting Hardware Included |
Yes |
| NAFTA Preference Criterion Code |
B |
| Oil Included |
No, No Filter Oil Required |
| Package Material |
Paperboard |
| Package Type |
Box |
| Product Box Height |
14.940 in. (379mm) |
| Product Box Length |
22.200 in. (564mm) |
| Product Box Width |
14.500 in. (368mm) |
| Product Style |
AEM Brute Force Intake System |
| Replacement Filter |
21-2100DK |
| RPM |
4796 |
| SDR Required Flag |
N |
| Standard Pack |
1 |
| Street Legal |
Yes |
| Street Legal In All US States |
Legal for use in all 50 states. |
| System Type |
Cold Air Induction |
| TUV Approved (Europe) |
No |
| Warranty |
Limited Lifetime |
| Weight |
11 lb (5 kg) |
| GTIN |
00840879013684 |
