I agree. But I think the better choices are Mahle, BMW and Mann, in that order. The photos show the K&N with the least Bt glow. But as soon as the bypass valve opens (and it will 5x faster than the Mahle), the K&N falls on its face. And the HiFlo had more Bt glow than all those others.

BestRest Products I wonder if it’s possible to recheck the k&n easily? I ask only because I watched a tear down of a handful of filters aside a Honda oem and the k&n had by far the stiffest bypass spring which is curious

As long as we used the same method of measuring bypass opening for every filter, it really doesn't matter. The chart shows which filter open too easily. That's not good. Easy opening means the filter media is bypassed.

@@bestrestproducts648 - did you measure the area of the bypass valves? The diameter of the bypass valve is not the same among oil filters. You have to calculate the PSI opening pressure based on the force and area of the bypass valve. A small difference in valve area can make a significant difference. Cool testing method by the way by using the UV glow material.

@@bestrestproducts648 Unfortunately, this isn’t true. If you only measured the spring force, that is only one component of a pressure measurement. Comparing spring forces of the filters tells you nothing at all about the pressure required to open the bypass valve.

We had no way to measure PSI, all we could do was measure force in pounds. Not engineers here, just a couple guys working with what we had.

@@bestrestproducts648 I understand. I just wanted you to know that measuring the force of the spring is essentially meaningless as the valve is opened by oil pressure and you need to know the area the oil pressure acts upon to relate that to force. A large valve with a 5 lb spring will open long before a small valve with a 3 lb spring.

Thanks for the feedback. Yes it was the FLO that was reusable. It didn't do very well. On a 'round-the -world ride it would be unlikely that you'd go 5,000 miles before you would find a place that sold filters. You could carry a spare. The filter on my 1200 is tiny.

I very much doubt that the BWW / Mahle filter bypass valves are wide open all the time. BMW wouldn't allow that feature, lest it cause issues. If the valve is open, the filter isn't doing anything. And since the BMW / Mahle had identical values (and every other filter had lower values), that means that all the other filters would be useless. . The Mahle and the BMW filters are identical in all respects, EXCEPT for that wire mesh screen. BMW's filter even has the brand name Mahle on the side (clearly Mahle is making the BMW filters under subcontract). So why is the UV image slightly different? I dunno. . As for the red herring of valve opening pressure and filter performance... A lower valve opening pressure means that the filtering material is bypassed, that's irrefutable. When it opens the oil goes right thru without any filtering. A lower opening pressure means that filter is useless. A higher opening pressure means the filter has a better chance of filtering (everything else being equal). . K&N had a pitifully low opening pressure. Although the filter media rated high based on square inches and thickness, it fell on its face because of the low opening value. . I think we can agree that the BMW filter is the baseline, the standard for comparison. Mahle is practically identical. All other filters must be held to that standard. . FYI - in my last oil change I used the Mahle. The costs and availability (Amazon next day) made the decision easy.

You are not understanding the pressure that the bypass valve sees. It isn’t seeing the pressure put out by the oil pump. Most engines run in the 30 - 60 psi range which means that all of the bypass valves would be open all of the time if they were activated by oil pump pressure. What the bypass valve sees is differential pressure in the filter. This is purely a function of the resistance to flow provided by the filter media. If there was no filter media, the differential pressure would be zero as if 60 psi was at the inlet of the filter there would also be 60 psi at the outlet of the filter and the valve would see 0 psi differential. Now let’s say the filter media provides 5 psi of pressure drop. The filter inlet still sees 60 psi from the pump, but the outlet sees 55 psi as 5 is lost passing through the media. Since the bypass valve is between the filter inlet cavity and outlet cavity, all it sees is the 5 psi lost while passing through the filter. If the bypass valve opens at 7 psi, it will still be closed. Now let’s assume the filter starts to get full of junk and the pressure drop through the media increases to 8 psi. Now we have our 60 at the inlet, but only 52 at the outlet. The bypass valve now sees 8 psi differential pressure and since it opens at 7 psi, it will be bypassing much of the oil.

I don't know the BMW spec. The BMW and Mahle valves opened at 12 pounds. See the chart in the video. Only the Wix had a higher reading. We didn't use a "lab" to conduct these these tests, but I once owned a Golden Lab, so I'm pretty sure I'm professionally qualified. As for the pressure readings we used a digital scale. We placed the filter housing on the scale, zeroed it, applied pressure to the valve, and recorded the weight needed to open the valve. Very low tech but very accurate.

Would it make any sense that a filter with more filtering media would need a lower bypass valve pressure because the pressure is being restricted much more by the more restrictive filtering media ? Also in combination with that would the k&n screen give it somewhat similar performance to those with less filtering media and higher psi to trigger bypass

@@Fee.1 My guess is that the more media (square inches of surface area) the less pressure is needed to get through the media. I would think that the bypass pressure needed could be lower in this case (and not get triggered as often) but seems like any filter should follow a "standard" for pressure needed to trigger the bypass regardless of filter media flow.

@@bestrestproducts648 It sounds like you were measuring the force required to open the valve, not the pressure. Force and pressure are quite different concepts. The only way to accurately measure the opening pressure of a bypass valve is to flow a fluid through it and measure the fluid pressure required to open the valve. The size and shape of the valve also affect its opening pressure, not just the spring force. It sounds like you measured spring force, unless I am not understanding your description of your method.

As each filter goes thru its life-cycle, it will accumulate more and more particulate. Eventually the buildup will be so severe that oil flow will be restricted. When that happens the bypass valve opens and the all the oil goes right past the filtering media. That's why it's important to change filters frequently. Motor oils can still do their job long after the filter needs replacing, which is why it might be a smart idea to replace them mid-way through your normal oil changing routine. Filters with a low opening value for the bypass spring (i.e. K&N) will open up during startup when the oil is cold, and it'll open up under moderate contamination build-up.

Nope. Too much work.

LOL. I don't know if there's a "best" filter, but the testing we did reveals the "worst" filters. Avoid those and you'll sleep like a baby... unless you start thinking about the "best" tire for your bike. In that case you'll never sleep.

Go to the BestRest Products website. At the bottom of the home page is an email contact

Didn't have one to test.