AEM® 20-402S - Nylon Air Bypass Valve (2.75")

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AEM® - Air Bypass Valve
AEM® - Air Bypass ValveAEM® - Air Bypass ValveAEM® - Air Bypass Valve on CarAEM® - Air Bypass Valve Installation InstructionMade In USAAEM Authorized DealerAEM Special Offers
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Universal Fit
Fitment Notes:
  • Not Vehicle Specific
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Product Details

AEM Accessories

Universal Air Bypass Valve (20-402S) by AEM®. Includes: 1 Bypass Valve. AEM's patented air bypass valve is cheap insurance for your engine. Should the air filter become submerged, the air bypass valve automatically takes over, shutting off induction from the filter and instead drawing air through the valve’s external diaphragm.

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Material: Nylon
Size: 2.75"
Includes: 1 Bypass Valve


  • Virtually eliminates the chance of the intake system ingesting water if the air filter becomes submerged
  • Installs along the upper portion of the air intake pipe
  • Includes complete hardware and installation instructions

Whether you cross over water when four-wheeling off-road or you drive in an area where the roads are frequently flooded, you should think about the possibility of the air filter on your cold air intake system becoming submerged in water. If your engine ingests water you could have catastrophic and expensive engine damage! The patented AEM Air Bypass Valve is cheap insurance against such an occurrence. The bypass valve installs on the upper portion of the intake pipe. If the air filter becomes submerged, the valve closes off induction at the filter, rerouting air through its external diaphragm to keep water out and air flowing in. The Air Bypass Valve comes with complete instructions and all necessary mounting hardware.

John Concialdi and Bob Sullivan co founded AEM® in 1987 as a tuning performance shop in Compton California. Both men had extensive technical backgrounds in engines and engine airflow, and in a short time AEM became the go-to company for performance modifications. By 1993, when the company relocated to Gardena California, it had become commonplace to see cars wearing the bright yellow AEM logo winning races. AEM tirelessly dyno tested and worked closely with racers and auto manufacturers in an effort to understand intake energy dynamics. This resulted in the sale of their first air intake kit in 1994. AEM can boast a number of firsts and unique products: They’re the first manufacturer to make an intake system with specific tube lengths and diameters to take advantage of pressure waves in the inlet tract; they developed the first dual chamber intake kit; they designed an air bypass valve to prevent hydro-lock should the air filter ingest water; and they created one of the first hybrid intake systems for modified cars. AEM continues to create innovative products to help you get more power from your car.

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Warranty Information

AEM warrants that its air intake systems and Dryflow™ air filters will last for the life of your vehicle. AEM will not honor this warranty due to mechanical damage (i.e. improper installation or fitment), damage from misuse, accidents or flying debris. On air intakes AEM will not warrant its powder coating if the finish has been cleaned with a hydrocarbon-based solvent. The powder coating should only be cleaned with a mild soap and water solution. Proof of purchase of both the vehicle and AEM part is required for redemption of a warranty claim. This warranty is limited to the repair or replacement of the AEM part. In no event shall this warranty exceed the original purchase price of the AEM part nor shall AEM be responsible for special, incidental or consequential damages or cost incurred due to the failure of this product. Warranty claims to AEM must be transportation prepaid and accompanied with dated proof of purchase. This warranty applies only to the original purchaser of product and is non-transferable. Improper use or installation, use for racing, accident, abuse, unauthorized repairs or alterations voids this warranty. AEM disclaims any liability for consequential damages due to breach of any written or implied warranty on all products manufactured by AEM. Warranty returns will only be accepted by AEM when accompanied by a valid Return Merchandise Authorization (RMA) number. Credit for defective products will be issued pending inspection. Product must be received by AEM within 30 days of the date RMA is issued. If you have a warranty issue, please contact AEM and thier customer service department will assist you. A proof of purchase is required for all AEM warranty claims.

Magnuson-Moss Warranty Act:
Legally, a vehicle manufacturer cannot void the warranty on a vehicle due to an aftermarket part unless they can prove that the aftermarket part caused or contributed to the failure in the vehicle (per the Magnuson Moss Warranty Act (15 U.S.C. 2302(C)) Learn More

Vehicle Fitment

This part is universal

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