K&N's replacement air filters are designed to increase horsepower and acceleration while providing excellent filtration. We make over 1,200 different replacement air filters for the majority of vehicles on the road. These filters are washable and reusable and are custom designed to fit into your existing factory air box. Their drop-in design means adding performance is simple. With most vehicles you simply remove the disposable air filter and replace it with a K&N. See applicable instructionsheet for details. Our stock replacement air filters for street vehicles are covered by our famous K&N Million-Mile Limited Warranty and will be the last air filter your vehicle will ever need.

Application

2008-2015 Audi R8 4.2L

Rebates

K&N 20% Off Select Filters Quarter 3 Promo Sale

KN20%OFFSELECTFILTERSQ3SALE2026

K&N's 20% Off Select Air and Cabin Filters Quarter 3 Promo Sale, running from July 21, 2026, through August 24, 2026. For a limited time, customers can save up to 20% off select air and cabin filters across the K&N, AEM, Airaid lineup, making it the perfect opportunity to upgrade with high-quality Air and Cabin Filters. The sale prices are applicable only to purchases made within the specified sale period, from July 21, 2026, through August 24, 2026. No rainchecks or exceptions will be provided. Regular MAP Pricing will be reinforced on August 25, 2026. This sale cannot be combined with any other offers, discounts, or promotions. Co-ops will be honored.

Warranty Information

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K&N Warranty Info (PDF)

CARB warning

K&N E-0668 Specifications

KEY SPECS
MFG. Part #	E-0668
Brand	K&N

GENERAL
Material Type	Cotton Gauze
Overall Height	6.625"
Shape	Round Straight
GTIN Code	024844312167

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Fitment

2008-2015 Audi R8