When we're talking about oil flow and which filters do best with this, I think it's important to talk about what oil they were used with.
Petroleum oils which tend to sludge up with hot engines will cause high performance filtering units like Mobil 1 to become plugged up sooner than if a synthetic is used.
Other factors to consider include the engine and driving habits of the user. High and fast-revving engines cause a lot of problems when a large amount of oil is suddenly sent to the filter. This may cause the separation between pleats to be lost substantially increasing backpressure. Also the bypass valve may not flow sufficient oil under such conditions and lead to oil starvation.
In general, petroleum users should use "lower" quality filters. That is, ones that don't filter down to say 15-20 microns. They catch more sludge than solid particles. The Mobil 1 filter should only be used by synthetic users as a general rule IMO.
My favorite filter which is supplied to me by
SynLube and is manufactured by GM. It has a synthetic filter element which has a wire mesh backing to keep the pleats separate. It flows substantially more oil than most cellulose-based filters and can last up to 5 years which is important with a lubricant that has a 3000 hour service life. SynLube has advised me that most of the time, unless the filter was used on an off-road vehicle, that they seldom find anything in the filter element and the only reason for replacing the filter is that eventually, the filter element wears out. SynLube filters are labeled as Duraguard Gold or Hard Driver.
[ February 18, 2003, 12:22 PM: Message edited by: Houckster ]