The K&N E-0668 is a round, straight-profile replacement air filter for the 4.2L V8 in the Audi R8. The manufacturer describes it as a high-flow engine filter built on layered, oiled cotton gauze, and it is sold as a pair of reusable elements. The manufacturer says it is engineered to last the entire lifespan of the vehicle. Swapping out a disposable paper element for a washable K&N is the main reason owners consider this part, since the same filter can be cleaned and reinstalled rather than repurchased at each service.
The manufacturer says the cleaning interval is roughly every 75,000 miles under normal highway driving conditions, which it frames as about five years at 15,000 miles a year. It also says the media is designed to increase horsepower and acceleration, and it lists filtration of up to 99 percent. No horsepower figure is confirmed for this part, so buyers should judge the value on reusability and filtration rather than a dyno number. Searches for K&N E-0668, Audi R8 4.2 V8 intake filter, and reusable R8 4.2 air filter usually lead to the same fitment question, which is covered in the FAQ below.
The manufacturer recommends cleaning about every 75,000 miles under normal highway driving, which it equates to roughly five years at 15,000 miles per year. Cleaning intervals will be shorter for dusty or stop-and-go conditions.
The manufacturer lists the E-0668 for the Audi R8 with the 4.2L V8, 2008 through 2015. Application details vary across sources, so confirm fitment with the manufacturer against your VIN and transmission before ordering.
The manufacturer lists a No-Hassle Lifetime Limited warranty on this filter. Check the manufacturer's current terms for conditions and limitations.
