Much into here:
http://www.scuderiaciriani.com/rx7/oil_filter_study/
"Here is a fairly well designed filter, especially for the price."
snip: "The filter cartridge has an impressive surface area of 316 sqin,
which is very close to the AC Delco Duraguard.  The difference is that
Purolator's filter element is compressed into more pleats (51) than the AC
Delco.  This may restrict flow somewhat, but not as much in this model than
the Pure One.  It features a spring-loaded metal bypass valve and a nitrile
rubber diaphram-type anti-drainback valve"

The study doesn't like Fram:
"Fram-Years ago Fram was a quality filter manufacturer.  Now their standard
filter (the radioactive-orange cans) is one of the worst out there.  These
filters are manufactured by Allied Signal, Inc.  Please do not buy these
filters.  By boycotting it, we may be able to cause some change.  I have
personally had one if these filters fail and actually cause engine damage
due to bits of paper and glue floating around in the engine.
For some inside dirt on Fram filters, see this email from an Allied Signal
production engineer."

.. goes on to say that it has 193 sqin of surface filtering area ...
compare that to the Pur's 316.

bob

----- Original Message -----
From: "Al and Sue Brase" <albeeee@MCHSI.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Sunday, March 13, 2005 12:47 PM
Subject: Re: Denver Parts House

> If in a pinch and can't find a German filter (Mahle or Mann), perhaps
> the next best chouce would be a Purolator. I've seen good reviews of
> them on the internet. My own dissections have confirmed their quality.
> (It has also confirmed the apparent low quality of Fram.) Advance Auto
> Parts sells them for sure around here( Midwest).
> Al Brase
>
> Stan Wilder wrote:
>
> >Most NAPA or PepBoys parts counters can supply what you need.
> >If you want Mahle or Mann filters you'll probably need to go by a Dune
> >Buggy
> >shop in the area.
> >
> >
> >
>