Ducatiz's Filter Forensics (you will like this)

I finally got time to do surgery on the filters

Special thanks to RB, Langanobob, and dlearl476, who contributed brand-new filters for this tomfoolery!

FYI ALL PHOTOS ARE THUMBNAILS, CLICK FOR BIG-ASS PICS:

(Group shot of the victims:)

HiFlo HF153
K&N KN153
Baldwin B7292
Fram PH6019
Parts Unlimited 01-0066
Perf-Form OF-0008

All of this took place in my high-tech forensic laboratory (I love Harbor Freight):

Tools:
Handheld bandsaw
60 lb table vise (sans table)
5 lb electronic postal scale, accurate to 0.1 oz.
Beer

Summary:

What I was looking at here was filter construction. Filter performance is much trickier to measure, esp since I don't have the setup to run fluid testing. I was more interested in what is inside these filters. All filters perform well within some limitations, and obviously we all want the best flowing, highest filtration, lowest rate of failure. I can't answer the first two here, but I think construction affects rate of failure and you can learn a lot by poking around inside them (or just gutting them and taking pictures...)

There weren't a LOT of surprises. All of the filter elements are about 2" (47-51mm) except for the Fram, coming in at 42mm. The backflow diaphragms varied from a sub-1mm flat piece of rubber to the 5mm thick monster in the Baldwin. You will NEVER get backflow in a Baldwin filter, that's my guess. Additionally, all of the filters had metal ends with metal crimped edges. That is a big difference than some of the paper/glued ends I've seen on some car filters (cough cough.. Fram..cough)

One big "AHA!" moment was figuring out that the HiFlo and K&N are the same filter. Period. Except for the red dyed element and the nut on the K&N, the two could have rolled off the same assembly line. The filter elements are identical except for the dyed filter media. The diaphragm, spring, base plate -- all identical. The base plates both have the same tool marks, the filters have the same stamp/weld spots. I would stake my legal career on this. They are the same filter. Period. And this is not difficult to see -- the other filters' components vary significantly from each other (except for the Parts Unlimited and Fram, which are probably both made by Fram/Fiamm).

Unsurprisingly, the Fram filter was crap. I say this from a lifetime of being disappointed with Fram filters for cars and trucks. I would not use this filter unless you have no other choice. The backflow diaphragm is absurdly tiny, the element itself is paper, and so small. The filter construction seems decent though. The Parts Unlimited is identical, except that they used a taller element -- but other than the height, the elements are identical, same tool marks, same bends. I doubt either will fail on you with short mileage, but I would not plan to take these to the track or use them for significant amounts of time. I could not believe the backflow diaphragms in these filters though. Pathetic.

The Baldwin filter was both impressive and disappointing. They use a paper filter element, which is fine, but is not as good as modern materials [[**edit I've been informed that the Baldwin filter uses a composite poly and paper element]]. On the other hand, the filter's construction was remarkably solid. It has more convolutions than all of the other filters (folds per inch). The backflow diaphragm is monstrous, by far the heaviest of the lot coming in 0.3 oz and more than 4mm thick. Compare that with the Fram/Parts Unlimited diaphragm which did not even register on my scale and is less than 1mm thick. (a postal scale, accurate to 0.1 oz). Maybe I need to pull out my old finger-postal scale.

One comment about filter medias: I don't have the ability to test the actual materials. Poly and composite filter media has fibreglass, which glistens under light so you can quickly tell which filters use poly or composite (which is poly and paper together). Also, when wet with oil, they do not change color like paper since they are not real fibers to absorb fluid. They are also generally superior to paper. Filter paper is pretty good stuff and comes in a variety of qualities/strengths so I wouldn't automatically discount a filter using paper versus more modern poly.

I also weighed the various components to get an idea where the weight lay. The lightest filter was the Fram/Parts Unlimited at 8.8 oz. I thought this was odd at first since the PU filter is about 0.25 inches taller, but opening it I saw why. The outer shell + bottom plate is the bulk of the weight. I think the chromed surface of the Fram made it a bit heavier. The heaviest was the K&N at 10.8 oz which isn't surprising given they spot weld a nut on the top. And it's not really a nut, it is a pressed-metal cap with a nut-like hex at the top. For each filter, I measured the element height (they all had the same diameter), weighed the element, the diaphragm, and then the "shell" which is the completely outer shell including the bottom plate (minus some metal from my bandsaw).

One thing I don't comment on is the spring. All of these filters have a spring behind the element which pushes the element against the baseplate. This helps with sealing the backflow diaphragm. I examined all of the springs and they all look sufficient. That's all I have to say.

Another thing I couldn't do too much with is the bypass spring/valve. All oil filters have a bypass mechanism in the top of the element which allows oil to go thru - unfiltered - if the oil pressure inside the filter is too high. This is often the result of a dirty filter, but can be caused by other things like a surge in pressure. Testing this would require more than I have the ability to do right now. Ducati filters are supposed to have a bypass at about 8 psi.

I also decided to rate each filter with a letter grade. This is totally unscientific and based on my unprofessional opinion of the filter's CONSTRUCTION and my examination of COMPONENT QUALITY only, nothing else. I kept in mind my experience with a Ducati factory filter, which I assign an "A" to.

Here is the data, accompanied with photos:

Hi Flo HF153
Weight: 10.2 oz
Element: 51mm tall, composite media (poly or poly + paper)
Element: 3.1 oz
Shell: 6.4 oz
Diaphragm: 0.2 oz
Rating: B+. Very good overall, quality welds, thick baseplate. Bypass mechanism is solid, poly filter has a lot of convolutions, and backflow diaphragm is very good.

Parts Unlimited 01-0066
Weight: 8.8 oz
Element: 51mm tall, paper filter media
Element: 2.8 oz
Shell: 5.6 oz
Diaphragm: 0 (less than 0.1 oz)
Rating: C-. This filter is reasonably well built, but the paper filter media with a lower number of folds and the pathetic backflow diaphragm means it can't score high. The construction isn't bad, but the components are less than stellar.

K&N KN153
Weight: 10.9 oz
Element: 51mm tall, composite media (poly or poly + paper)
Element: 3.1 oz
Shell: 7.1 oz
Diaphragm: 0.2 oz
Rating: B+. Same as the HiFlo. Very good overall, quality welds, thick baseplate. Bypass mechanism is solid, poly filter has a lot of convolutions, and backflow diaphragm is very good.

Perf-Form OF-0008
Weight: 8.9 oz
Element: 47mm tall, composite media (poly or poly + paper) (Their website claims 100% poly)
Element: 2.7 oz
Shell: 5.6 oz
Diaphragm: 0.1 oz
Rating: B-. Good overall, quality welds, heavy baseplate. Bypass mechanism is solid, poly filter has a lot of convolutions, and backflow diaphragm is good but lighter than the HiFlo or KN. Perf-Form has a lot of info about their filter media on their website.

Baldwin B7292
Weight: 9.8 oz
Element: 48mm tall, paper media
Element: 2.4 oz
Shell: 6.7 oz
Diaphragm: 0.3 oz
Rating: A-/B+. The only downside of this filter is the paper media, but I might be wrong about that, it needs to have its flow rate tested. It is a VERY dense fold filter, with a very significant number of convolutions. The Element is shorter than the others, but by about 6-7% which can be made up by the folds. The diaphragm in this filter is something to behold. I would use this filter any day.

Fram PH6019
Weight: 8.8 oz
Element: 42mm tall, paper media
Element: 2.5 oz
Shell: 5.9 oz
Diaphragm: 0 (less than 0.1 oz)
Rating: D+. This filter is reasonably well built like the similar Parts Unlimited, but the MUCH shorter paper filter media with a lower fold count and the pathetic backflow diaphragm means it can't score high. The construction isn't bad, the baseplate is good, but the components are crap.

Comparing the K&N and HiFlo side by side:
Top of elements:

Their diaphragms are indistinguishable:

Filter elements are identical except for color. Tool marks, welds, everything in the same place.

Base plates are identical. Same welds. Side view of the diaphragms. Very good quality.

Comparing the Parts Unlimited and Fram.
Baseplates are identical, diaphragms are identical, but what is up with the elements?

PU version is 51mm tall, the Fram is 9mm shorter. Both look the same otherwise, same construction. I would say the filter elements are well constructed, but are not high-tech poly, they are clearly paper.

Baldwin vs Fram

The Baldwin is only 48mm but towers over the Fram 42mm. The Baldwin filter is built like a tank, but comes in very light. The element is paper, but it could be poly. The number of convolutions is very high, over twice the number in the Fram.

Baldwin monster diaphragm vs Fram's condom-thickness version

This is all 6 diaphragms in order: Hiflo, KN, Perf-Form, Baldwin, PU, Fram. You can barely see the last two.

This is my Ducati factory Filter I cut a while back. I did not weigh or measure it except for the element. Just for reference:

Filter element is 51mm

Well constructed inside.

Heavy diaphragm and unusual metal spring retainer for it.