WE USE THEM OURSELVES....
Trying to stay out of a pissing contest here, but JA and I and a lot of friends around us use these in street (performance) applications as well as race. It's an old story but if you haven't heard it, we screwed up his FE for the 63 1/2 Galaxie when we wiped the flat tappet cam on the dyno while trying some experimental rocker arm adjusters. We thought about an adapter to run a Chevy filter, but decided to design and see if we could get some filters manufactured to our specs.
Things like multi-vis oil, proper warm-up, oil pressure gauges and even idiot lights make running no-bypas filter kind of a no-brainer, but as I've stated elsewhere YMMV! Our filter has over twice the media area of some of the competitors, more than any we've cut apart, and is 18-20 micron rated so it flows a lot of oil and stops the important chunks.
We don't "pressure" anybody to run the no-bypass filter, just try to provide the facts and let people decide for themselves. No hard feelings if you feel more comfortable with a bypass valve.
BTW, JA (Old Jomar) and his previous partner probably built over 3000 engines all with bypass blocked (Chevy) or remote full-flow filtration on Fords etc. Never had a problem with somebody "plugging" a filter and destroying an engine.
My question is this - what the heck is plugging the filter (given the issue that previous posts have referred to as in "street" application) and what would be the advantage of having a bypass valve pop open and distribute all that junk to the bearings and piston skirts?
We've had reports from a dozen or more customers who have wasted cams, lifters, roller rockers etc. (and my MSD distributor base) and who have had all of the junk get captured in the filter. It will hold a lot of debris before the oil pressure drops, and I don't think that anybody was unaware they had a problem. I just can't logically conceive that a drop in oil pressure will be the first indication that something is wrong!!!
Hope this doesn't muddy the waters too much.
ps. we've flow tested and cut apart about every major brand (Ford app.) filter out there - and they all have bypass valves. And most of them had more pressure drop at 8 gpm with their little bypass valves open than ours did still running "full-flow".
As far as "conventional" filters go, we can state with relative certainty that FL1-HP, K&N, Mobil one, and Moroso are all very good filters - with the caveat that some of these vendors appear to have a tendency to vary their product's construction without notice - perhaps shifting to a lower bidder.... There are just not that many manufacturers making filters in the USA anymore. It comes down to initial engineering, specification, testing, and then checking each shipment to make sure the filters are actually what were ordered.
Last edited by jpb6061; 03-19-2009 at 06:03 PM.
Reason: additional info