# comments on the Purolator replacement air filter...



## 31st330i (Jan 11, 2002)

the first thing I noticed about this filter is that it looks almost exactlly like the OEM filter, down to the molded orange frame. the paper is just a slightly different shade and Purolator doesn't have the layer of foam.

there is absolutly NO price advantage to using this filter. at PepBoys, it costs $16.99. a BMW filter from pacific and I presume cutter is $11.80.

the reason I got this filter was for my little ESIS project. I wanted to measure the surface area and this filter doesn't have the foam layer.

well, the bad news is that it has slightly less surface than the stock filter.

Purolator:
number of pleats: 56
width: 160mm
pleat depth: 47mm

stock:
number of pleats: 78
width: 163
pleat depth: 36mm

when calculating the surface area, be sure to double the pleat depth because each pleat has two sides.

anyway, unless the Mahle filters have any better surface area, using the older E36/Z3 2.8 filter will have the most surface area. they are essentially the same filter but the older one doesn't have the foam layer. overall height on both of these filters is the same so the newer filter has shorter pleats to accomodate the layer of foam (which is for noise muffling and perhaps prolonged filter life).

here's a pic from Shawn Fogg's page.










here's teh page I nabbed the pic from:
http://ackthud.com/shawnfogg/2_3lairbox.htm


----------



## 31st330i (Jan 11, 2002)

forgot to mention.... the Purolator filter I used was A45105. in teh old book hanging on the shelf at pep boys, this filter is listed for almost all E36, E46, E39 and Z3 6 cylinder cars. there was a note by the part numbers for the E46 cars that this filter would no longer be available. on the purolator web site, they list a new part number with a note stating "available soon." I'm guessing that they're revamping the E46 filter to give it a foam layer like the OEM one.


----------

