Air Filter Study, Flow Rate and Filtration Options

[pvollma]

I found the link to this study on a Lincoln Town Car forum:

Air Filter Comparison Study

While it was done using air filters for a GM Truck, the conclusions are interesting:

1. choosing a filter type or style for ‘more flow’ for either performance or fuel mileage is useless, as they all flow about the same

2. there is a wide variance in the ability to filter contaminants; the best was an unoiled synthetic fiber passing less than 1% of the contaminants introduced, while the worst was an oiled foam allowing 40% to pass. To bring in some 914 relevance, the K&N was second-worst, passing 35%.

I make no claim that this applies directly to our 914s, but I found it interesting since I've always used K&N filters on my performance cars.

[Chi-town]

That is classic forum crap

I see these tests on every forum there is but there are always variables not taken into consideration such as air box design, acoustic tuning of intake manifolds, and many others when it comes to flow.

A flow bench made from a used MAF sensor (and one that was known to be inaccurate even when new!) and a 5hp vacuum is useless.

Every car is different, pick up a few different filters (foam, cotton, synthetic), strap your car to a Dyno and see which one works best for you.

As far as contamination, let me know when you find a pile of 5 micron dust in your intake (IMG:style_emoticons/default/laugh.gif)