Originally Posted By: goodtimes
Originally Posted By: Jim Allen
Originally Posted By: goodtimes
My two cars I service, still doing even at this point in life, are easy to change the filter on. New filter every time with fresh clean media is what I want. Graph supports this. I want the least restriction everywhere in the oil filter. The notion large pores fill first is counter intuitive. If it was the case, the Fram Ultra would have it's inner fine layer on the outside and the coarse on the inside. Coarse screens would clog before fine screens, which just isn't so.
Graph does NOT support this! One snippet, where all the parameters are not known, is not the whole picture.
One thing we do know is that the test artificially fed high amounts of contaminants to load the filter quickly. That isn't anything close to the real world, unless your real world involves dumping dirt into your crankcase or running without an air filter in the Sahara Desert for 5,000 miles. You are WAY overestimating the amount of contamination a normal engine in the real world generates. A good wearing engine is a product of it's design and the lubricant. Modern engines, especially those with roller cams and no timing chains, once broken in, generate very little in the way of wear metals. An average oil filter can hold 16-18 grams of material before it reaches a high enough differential pressure that it begins to bypass often. If 18 grams of metal, about 6/10s of an ounce, came from various parts in your engine over a normal OCI, you'd have other things to worry about besides whether your oil filter was full.
Much, most, of what a filter catches is other stuff... dust that gets in through the intake somehow, carbon or soot, and oxidation residue. If you eliminate/minimize what comes in thru the intake, and eliminate the oxidation residue part by using a good oil and having a good driving routine, all you have left are combustion byproducts like carbon and soot (in a diesel). These can be minimized as well and the efficient combustion of a modern EFI engine does that... especially if the owner uses good fuel that leaves few deposits or ash. So when you get right down to it, there is very little for the oil filter to do with a modern EFI engine... if the outside inputs are low... and that's why oil filters can last a long time. Different deal on old school engines.
I have asked for an average engine contaminant generation rate from various industry people and they don't have one. If it's ever been tested, it would be specific to one engine in a particular situation. The only answer I get is "low" with the caveat that "low" only applies to engines with efficient air filtration systems. Almost everyone agrees that an efficient air filtration system is the most important part of controlling contamination inputs. Anything that comes into the combustion chamber is going to get into the oil. Those particles will cause wear, which creates more particles and an endless chain of wear is begun. In many ways, the air filter is the most important part of having clean oil, low wear and long life. An efficient oil filter comes into play more when there are high contamination rates from outside sources...such as from an inefficient or defective air filtration system.
On top of that some oil filters have higher than average capacity. As I said, from the specs I've gathered, the average sized oil filter can hold 16-18 grams. Some premium (syn) filters can hold around 30 grams before nearing their bypass limit. If you want to know how much the filter you use can hold, ask the mfr.
As to FCI recommendations, most of them are based on a CYA. Filter mfrs want the engine manufacturer to take responsibility for that. If you see a 3K interval, there is usually a caveat nearby that says "or according to the OEM recommendation." A "worst case" situation is envisioned and then it's given a safety factor (in industry typically X2 or X3) and there you have it... CYA.
"You are WAY overestimating the amount of contamination a normal engine in the real world generates."
Not really, what you said above about the multiple pass test is what I have also been saying for a couple years or more, with no takers. Motorking from Fram has stated one gram per thousand miles is an average contamination value. That is a completely different use situation than the multi pass test represents. The multi pass test has to be done in some kind of cost and time frame is my take on it, and the values do represent something tested, but not like real world use unless one is driving in a dust storm without an air filter. I also hold an unpopular view that a cellulose synthetic blend is better than full synthetic because cellulose, being made from wood fibers, is a far finer filter over time. Synthetic fibers don't absorb, cellulose does. Cellulose even traps water molecules.
Yep, I think I have been quoting the 1 gram/1000 mile for ten years or so. Not sure where I got it. I think from Parker Filtration. I think many engines are far less than that, especially if you consider the statistic may apply more to older engines than today's. BUT using that number, it would take 16,000 miles for the average engine to plug an average filter. With that spec, once you know the capacity of YOUR filter, you could estimate a useful FCI with whatever safety factor you deem appropriate. For my late Ford it was over 30K miles... not that I would have gone that far. Well, I might have after I installed a 3 micron bypass system on it, but that turns this into an apples and oranges thing.
I agree with you about the cellulose media... and it shouldn't be popular, unpopular or a "viewpoint" at all. It's a FACT, making it worth consideration. I considered it in the evaluations for my personal filter choices but concluded since my driving cycle is such that the cars are almost never short hopped, I don't need that capability. I would rather have a more durable, freer-flowing media (flows better with a higher efficiency rating... plus I am somewhat obsessed about cold start bypassing). Because I live in the boondocks, my rigs are almost never run less than 10 miles at every start (@55-60mph)... usually lots more. So they are almost always run long enough to evaporate moisture by heat. May not be true of everyone, so a cellulose media (or a blend) would be a choice worth considering for some folks.
