That depth filtration OEM JDM Toyota filter is pretty interesting. (If I was still running a spin on disposable filter, I'd go that route now.)
But I belive that depth filtration on both your full flow and bypass filters are the way to go.
Canton makes spin on adapters that will fit the 7M. They use replacement filter elements that run about 15.00 each, but you only have to change them every 25k or so if your running synthetic oil, and you should have your oil analyzed at 10 to 15k, and see how it's doing. If it's in good shape, change your filter at 25k, and top off the oil.
If you run a true bypass depth filter like I do, you could do like JetJock suggests and run your oil pretty much forever if you use the right oil, and change your filters every 25k. (Just to be sure, have your oil tested every year if you want as well.)
Here is the facts.
Your spin on filters (Except for that depth type JJ posted, and possibly some of the new spun media filters) will stop most particles down to about 20 microns in size. Some are slightly better, but most are quite a bit worse only stopping particles down into the 40 micron range at best.
Wear is caused by particles larger than 10 microns according to agreed on sources. (There is some debate on this, but not at our level anyway
)
A good bypass filter will trap particles down to 1 micron or better. A simple and very old design uses a roll of toilet paper compressed into a can that the oil is then pushed through. It comes out the other end very clean, and TP rolls are pretty cheap to replace. Paper when soaked with oil is actually very strong, so the likelyhood of the TP roll coming apart is slim too.
Some of the new designs use celulose (paper by another name) material in woven or wound up cords v/s layers of pleated paper like the TP roll. All the designs are very effective at trapping debris down into the 1 micron or better range, so the oil coming out of these bypass filters is super clean. Possibly cleaner than it was when you poured it out of your container new. (not kidding here.)
So, why don't new cars have these filters built into them? I don't know, but it'd imagine it would have to do with how long the engine runs with clean oil all the time. (Why buy a new car when your old one is running so well? You do the math>)
The location for the vapor canister makes a great spot to mount a bypass filter. If your running a ball bearing turbo, you could even have the oil run through the bypass filter first, then into the turbo since BB CHRA turbo's really don't like excess oil pressure and volume.
I just used the normally plugged port on the main galley to the rear of the main oil return fitting on the block. You could just use a simple T fitting between your turbo and your bypass filter, and use the stock oil cooler dump to return the super clean oil back to the pan. (That's where mine dumps.) I use a full flow cooler and thermostat.)
So, recap. Full flow, depth filter from Canton, blue canister with a AN10 going in, and AN10 going out, and replaceable Mecca filter inside of it that you change every 25k. (It filters ALL of the oil all of the time down to 8 microns.)
Green topped oil guard bypass filter in the vapor canister location, it filters some of the oil from the main galley, and then dumps it back into the pan. The maker estimates that about every 45 min of operation, 6 quarts of oil passes through the filter. So every hour I drive my car, most of the oil in my engine has passed through the bypass filter, and if I really want to clean my oil, I could take the car out for a long drive of 8 hours or so, and get it really clean...This filter I plan on changing every 25k depending on how the oil samples come back. (I only have a few thousand miles on the engine at this time, but have changed the oil from the group III 30 weight oil I used for the initial fill. I also changed the filters in both to get rid of the assembly lube and any huge debris that all new engines have laying around that you just can't get out of the engine any other way for some reason.)
