how about a different perspective?
air filter and oil filter.

article belongs to TMOE and need to have an account to access website. register for free.
http://members.themotoroilevaluator....dex.php?id=152


Now, with all of that being said regarding quality control practices, we have still not gotten around to a DETAILED discussion of filtration efficiency and capacity which are so critical to everyday engine protection.

Many OEM brand filters are still using cellulose based filter media (while the structural components are normally of good quality to prevent "failure"). This is not true of ALL OEM oil filters, but many of them.

As such, their filtering efficiency and capacity are not nearly comparable to a high end, high efficiency oil filter using synthetic and possibly even the newer nanofiber media technology to not only increase efficiency but also capacity.

Capacity is an issue in the sense that, the lower the overall capacity of the filter, the sooner it will need to be changed. So, if the filter is being saturated with particulate and it offers low capacity, it won't be long before the bypass valve needs to open to maintain oil flow.

As long as this valve is open, oil flow is maintained, but no filtration is occurring, thus, dirty oil is circulating throughout the engine. If the media is saturated and the bypass valve fails, little if any oil flow is maintained and oil starvation will occur.

So, function of the bypass valve is important, but filter capacity is also important if you're not changing your filter very regularly because it can have just as much affect on oil flow. Many OEM filters are not super high capacity filters. Thus, they should be changed fairly frequently to avoid having them end up in "bypass mode".

Certainly, there are high capacity filters on the market. But, of course, filter capacity is really only a factor in establishing HOW LONG a filter can be effectively used to remove engine oil contaminants. It really has no bearing on how WELL the oil is filtered.

That is where filter efficiency comes into play, and this is also a very important issue, which, intuitively would make sense, but many people I don't think put enough weight on this issue.

In paper 881825 the SAE indicates that a joint study was performed between AC Spark Plug and Detroit Diesel Corp. The study found that finer oil filtration significantly reduced the rate of engine wear.

According to the paper, the tests regarding engine wear within gasoline engines were run at 40 microns, 30 microns, 25 microns and 15 microns (diesels were tested as well, at somewhat different micron ratings with similar results).

The researchers had this to say:

"Abrasive engine wear can be substantially reduced with an increase in filter single pass efficiency. Compared to a 40 micron filter, engine wear was reduced by 50 percent with 30 micron filtration. Likewise, wear was reduced by 70 percent with 15 micron filtration."

Most cellulose media based filters offer an absolute filtration rating of 40 microns - some as low as 30 but not many. A high efficiency synthetic media filter generally will offer absolute filtration efficiency at least as low as 25 microns, with at least one offering absolute filtration efficiency down to 15 microns.

According to the study, moving from a 40 micron cellulose media filter to a 15 micron synthetic media filter, engine wear would be reduced by 70%.

In fact, although it takes a little extra math to figure this out, even if you give cellulose media filters a generous 30 micron absolute efficiency rating you'd still see a 40% decrease in engine wear by moving from a cellulose media filter to a 15 micron synthetic media oil filter.

This is not filter company propaganda. Detroit Diesel had no vested interest in trying to show high efficiency oil filters to be better than cellulose media filters. That's just how the testing came out.

So, the question is, how much is that 40% or 70% decrease in engine wear worth to you? Is it worth taking the time to REALLY investigate the issue a bit to find a filter that offers you the qualities you need? Is it worth paying a bit more for your filters in order to get those qualities? I think so, but, you'll have to make your own decisions when it comes to the protection of your own vehicle.