I personally am open to non-OEM parts if I have confidence that the parts
meet the requirements. This comes down more to believing in the company
making the parts, or getting access to the specs of the part. I use
non-OEM filters (such as Amsoil, Mobil-1 etc.) but there are some brands I
will not use, such as anything FRAM, which has recently gotten the repuation
of being junk.
I cut open a Yamaha OEM filter and compared it to a Amsoil filter (SDF-20,
which fits late model Honda cars and the GTS), and both appeared to be very
high quality for an oil filter. keep in mind that they have to make these
things for about $2 to $5 each (for the better ones) and still have to make
a profit. There was nothing I saw that made the Denso filter better, other
than the color. The Amsoil had higher capacity (slightly bigger filter). I
also had my dad (the late Joe Crisler Ph.D chemist) examine the filter
material and case under a microscope. He has a great deal of experience in
filtering material, and he pronounced the Amsoil filter a bit better than
the Denso filter, but he was not sure if it would make a difference in the
real world.
The Amsoil would filter to a finer degree (remove smaller particals). This
is good. What is bad is that it can restrict oil flow more than a coarser
filter. This was offset by the fact that the Amsoil was much bigger, and
had more filtering area. He felt this offset the reduced flow because there
was more than enough fitler area to offset the flow rate, so the total flow
capacity should be better than the stock.
Now, he could only eyeball it and use a microscope. We had no access to
any gizmo that would actually do flow testing/filtering testing, although he
used that stuff way back when making machines for making propellent for
missle motors. (Posiden, Trident, Sidewinder, Sparrow etc.). He was mostly
solid rocket motors, but also worked on liquid fuel too.
Somebody has a website somewhere where he cut open and examined tons of
filters. I will try to find the link.
