Why should I upgrade my OEM Air Filter?

By: David John Stevenson

Changing your stock restrictive OEM air filter to a high flow reusable filter should be one of the first modifications performed on any vehicle. Time and time again, independent airflow tests have shown that high flow filters allow more airflow into your engine, thus creating an increase in horsepower and improved fuel economy. 

Contrary to popular belief, changing your stock filter to an aftermarket unit will not void your new car warranty.  In 1982, The Magnuson-Moss Warranty Act was passed.  This Act makes it illegal for a manufacturer to void a new vehicle warranty if the consumer decides to use a non-OEM filter unless that manufacturer provides filters free of charge.  If your vehicle's manufacturer does not provide replacement filters free of charge, they cannot void that vehicle's warranty simply because you have installed an aftermarket filter. 

Stock OEM filters typically use bonded paper as the filter media, which is easily clogged by dirt, oil blow-by and moisture.  For this reason, paper filters are disposable and may only last up to 10,000 miles or so in the best case scenario.   Most reusable high flow filters use either porous foam or the more popular multi-layered cotton gauze.  The cotton gauze approach allows higher airflow capabilities but with the added benefit of maximum filtration.  Prior to installation, special oil is applied on these filters to catch dirt particles and help prevent the cotton gauze from drying out.  Cotton type filters are easily washed using dedicated cleaning solutions that loosen embedded debris and rinsed clean with regular low-pressure tap water.  Because of their superior designs and low maintenance, some aftermarket cotton filters can last up to 50,000 miles or more without servicing.  However, under extremely dusty and or off road racing conditions, it is recommended to clean high flow filters at smaller intervals or just simply when needed.

The only considerations when upgrading the OEM filter is the initial cost of purchase and the added intake noise associated with more airflow.  Although more expensive than a paper filter, the initial cost is still very reasonable and will pay for itself after only a few tune-ups. Disposable paper filters will cost you at every tune up but reusable high flow filters are bought just once and should last the entire life of the vehicle. The added intake noise is not that severe under normal throttle and many enthusiasts actually prefer the new sound to stock.  

This modification is extremely cost effective at approximately $50-$60 for the typical drop in type filter that replaces the stock OEM filter located in the factory air box.  Installation times may vary but most applications are fewer than 10 minutes.  Quick, cheap and easy sounds good to me…how about you?