Comparison of OEM and K&N oil filters for Ducati motorcycles
We at TPO parts work on Ducatis regularly. One thing that you will hear from many Ducati mechanics is that you should only use OEM oil filters. That can be a major inconvenience with Ducatis. The OEM filters are hard to find and they are also very expensive. We were excited when we heard that K&N--makers of what is probably the world's best performance air filters--started making oil filters for Ducatis. We decided to purchase one and sacrifice it in the name of science to see just how they compare to the OEM filter. In this article we will show you the step-by-step dissection and comparison of an UFI oil filter (Ducati's OEM supplier) and a K&N Ducati oil filter. You will be able to see exactly how the two compare...and we think the results will be suprising!
Here you can see our test subjects. One K&N filter and one UFI brand filter. UFI is the OEM supplier for Ducati, and this filter is exactly the same as the filters that come factory installed on Ducatis. The ugly tool in the foreground is an oil filter cutter. This tool works a bit like a can opener. It allows a mechanic to open up an oil filter so that he can inspect the inside for engine debris. Race mechanics do this becasue it lets them monitor the condition of an engine without having to tear it down. The practice of opening and inspecting used oil filters is common in all forms of motorsports. We'll get to that part in a little while.
First looks: Out of the box.
Here you can see the K&N filter (left) and the OEM filter (right). The K&N filter came with a heat-shrunk plastic cover over the open end of the filter. The OEM filter did not. You can see some cardboard particles from the box are inside the OEM filter. That doesn't make me very happy, but then again cardboard bits are not likely to cause problems. The mounting plate of both filters are essentially identical, and so are the gaskets.
Here you can see the filters flipped over. It is a bit difficult to see in the photograph, but the K&N filter has a "nut" welded to the top whereas the OEM filter is smooth. This means that you can use an ordinary wrench to tighten or loosen the K&N filter. This is a very handy feature. If you have ever had to remove a "stuck" oil filter, you would be very happy to have this feature. No more fumbling with strap wrenches or the infamous "screwdriver trick". Furthermore, the nut has holes in it so you can safety wire the filter to your bike. This is very handy for those of us that race. The following two photos show the K&N nut in more detail:
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Surgery time: A look inside the filters:
Here we have cut open the filters and laid out the internal parts. The OEM filter is on the top, and the K&N filter is on the bottom. The parts, from left to right, are:
- The outer shell or housing
- The spring, which seats the filter against the mounting plate
- The filter core itself
- The anti-drainback valve (this keeps oil inside the engine when the motorcycle is parked)
- The mounting plate
- The box
However, if we look closely we can see a few differences.
First, the K&N filter has a taller core. This could mean that it has a higher surface area, and therefore can trap more dirt while having a lower pressure drop. We will investigate this further later. You can clearly see the difference in cores here:
Also, the K&N core uses resin-treated paper (notice the red color) whereas the OEM filter has plain paper media. Resin-treated media lasts longer and offers better filtration than plain paper.
Finally, the OEM filter has a plain rubber anti-drainback valve, whereas the K&N valve is made of silicone rubber. Silicone rubber has better chemical resistance, maintains better flexibility (which means better sealing), and it also can withstand much higher temperatures than natural rubber.
At this point it is clear that the K&N filter has some significant advantages over the OEM filter.
A closer look inside the filter cores:
Now we have cut the filter media away from the metal core. This will let us examine the cores and the media in more detail.
Notice that the OEM core (on the left) is obviously shorter than the K&N core. You can also see that the OEM inner core support has relatively few holes, whereas the K&N core has more holes visible. This means the K&N core can support higher oil flow.
Now let's see how the filter surface area compares. We took the filter media from the core and laid it out on a workbench so that we can measure how much area it has.
Here you can see how we aligned the media and stapled it to a wooden workbench. Then we stretched it out so that it is flat and put down a measuring tape.
You can see that the OEM media is 57 1/4 inches long, whereas the K&N Media measures 65 1/2 inches long.
Now we can compute the area of the media.
OEM: 57.25 inches long x 1.25" high = 71.56 square inches
K&N: 65.50 inches long x 1.56" high = 102.18 square inches
The K&N filter has 43% MORE useable filter area than the OEM filter.
Conclusions:
Based on examining these filters thouroughly, it is clear that the K&N filter is superior to the Ducati OEM filter.- The two filters are of comporable mechanical construction.
- The K&N filter has a nut for easy installation and removal, whereas the OEM does not.
- The K&N filter is able to be safety wired. The OEM is not.
- The K&N filter has a silicone anti-drainback valve that is more durable than the OEM.
- The K&N filter has superior resin-impregnated filter media.
- The K&N filter has a perforated core that can support more flow.
- The K&N filter has 43% more filter area, which means greater dirt holding capacity and less pressure drop.
