Rocky Mountain Club B5

Discussion Forums => Modifications => Topic started by: aowhaus on May 02, 2005, 01:13:41 PM

Title: DIY cabin air/pollen filter (instructions here!)
Post by: aowhaus on May 02, 2005, 01:13:41 PM
Considering OEM cabin air filters are not cheap to replace (especially the pollen ones) and a bit of a neusance to order, I've came up with a very easy and cheap way of making your own filter.

I've gone to my local Home Depot to pick up a furnace filter.  There are many kinds they stock, but the one you should use is the pleated air filters made by 3M or Lysol.  I highly recommend the Lysol Elite filter as it outperforms the 3M in particle capture rating.  Check the packaging, as all have a particulate number rating to indicate its performance (the higher the number the better).  The Lysol Elite filter captures particles as small as .3 mircons and filters out dust, pollen, mold spores, bacteria, insecticide dust and oil smoke.  This is better than the stock filter and comparible (if not better) to the OEM pollen filter.

Please note that these instructions are for a B5.5, if the B5 stock filters are 1" thick or more than this will work too.

A typical large furnace filter has enough material to make 4 cabin filters and the thickness is identical to a B5.5 cabin filter.  I just traced the outline of the stock filter on a corner of the furnace filter and cut with a sharp utility knife.  The reason why you will need to cut off a corner is that the cardboard edging helps maintain the shape of the pleats of the filter material.  

I then cut 1" strips of thin cardboard to use for the two cut sides.  Apply a layer of white glue to the edge of the pleated filter material and attached the cardboard strips to it.  I used masking tape to hold it in place while the glue sets.

I then popped the new DIY filter back in (the filter is directional, like the OEM ones, so remember to install it with the proper flow direction) and it's now ready to go.
The Lysol furnace filter costs about $9.99 which means that each filter you make out of that piece will cost $2.50, much cheaper than the $13-18 you could spend for an OEM one, and you could afford replace the filter more often to maintain optimal air quailty in your car.