# List of oil filters with 99% efficiency at 20 microns.

#### SC Maintenance

I call B.S. 99 percent at 20u will have better efficiency at 5u compared to 95 at 20u. Most wear comes from the finer particles.
If you measure 99% confidence vs 97% confidence in statistics its not 2%, its the difference in the integral between 99 and 97% which is way out into the standard deviations, and again, statistically not that much. Thats the statistical argument.

If you want to argue practicality, yes you might have a small percent fewer 5um particles, but anyone that builds engines will tell you a properly maintained engine isn't going to wear out from 5um particle before something else major breaks first.

Your also assuming that 99% and 97% are absolutes across every filter across every media run which is untrue. There is a acceptable tolerance, not to mention the ratings by the manufacture is based on some specific filter.

Not telling you not to run whatever filter you feel best with, but my comment that 97 vs 99% are statistically and practically are meaningless as presented by fact. Its not BS its math.

Now the difference between 20um and 30um at 99% is a different story.

#### Vern_in_IL

The purpose of an oil filter is.... filtering oil. I want the best performance possible, yes I know the best oil filter is the air filter. and this "properly maintained engine" argument is null when we are doing extended OCI's well beyond recommendations based(hopefully) on oil analysis.

Anyone running a 3k OCI does not need max efficiency oil filter. Also that 97% could become a 99% due to "loading" of the filter media. So yes, I am biased.

#### ZeeOSix

##### \$100 site donor 2022
If you measure 99% confidence vs 97% confidence in statistics its not 2%, its the difference in the integral between 99 and 97% which is way out into the standard deviations, and again, statistically not that much. Thats the statistical argument.

If you want to argue practicality, yes you might have a small percent fewer 5um particles, but anyone that builds engines will tell you a properly maintained engine isn't going to wear out from 5um particle before something else major breaks first.

Your also assuming that 99% and 97% are absolutes across every filter across every media run which is untrue. There is a acceptable tolerance, not to mention the ratings by the manufacture is based on some specific filter.

Not telling you not to run whatever filter you feel best with, but my comment that 97 vs 99% are statistically and practically are meaningless as presented by fact. Its not BS its math.

Now the difference between 20um and 30um at 99% is a different story.
You're talking about statistics of measurements and data. The ISO 4548-12 test procedure requires specific instrumentation and calibration accuracy. All a consumer can do is compare the rated ISO efficiency numbers when shopping for filters based on efficiency. Unless you want to pay a lot of money have them ISO tested by an independent test lab.

#### ZeeOSix

##### \$100 site donor 2022
Also that 97% could become a 99% due to "loading" of the filter media.
Actually, oil filters typically become less efficient as they load up and the delta-p causes already captured debris to dislodge and go downstream. It's been discussed many times in this forum. This is a possible negative of running oil filters way longer than what they are rated for.

#### SubieRubyRoo

Actually, oil filters typically become less efficient as they load up and the delta-p causes already captured debris to dislodge and go downstream. It's been discussed many times in this forum. This is a possible negative of running oil filters way longer than what they are rated for.
This right here is probably why HPL recommends 5k filter changes regardless of what you use when you’re running their EC or oil. To extract all the benefits of their oil, 3x filters over a 15k OCI isn’t that big a penalty.

Wish I had a bypass system, because with 5k filter changes and an 8-12 ounce top-up and all that glorious TBN, you could probably make it to 50k easy and still be safe from all the “no-no’s” this board reminds people to avoid.

Anybody done a bed-mounted Frantz? 😂

#### SC Maintenance

The purpose of an oil filter is.... filtering oil. I want the best performance possible,
Your absolutely correct - if your only given those numbers as the decision factor then yes, I too would choose 99%.

Lets phrase it differently - would you rather have 99% at 30um, or 97% at 20um? I am guessing most of the public would pick 99% @ 30um, and I actually don't know much about particle size distribution in oil, but assuming it follows some standard deviation odds are good that 97% at 20um is superior. Speaking mathematically.

My point is simply people don't understand how little statistical difference in the number 99% vs 97% for the same particle size, so its used by marketing - proof being they all print 99%* - and then in the fine print somewhere else it shows particle size.

#### Plawan

You guys are worried about 99, or wait 97.3556%. I've been working on engines and cars trucks etc,since high school auto mechanics.Not once have I had an oil related failure worrying about such ridiculous miniscule difference between oil filters is a waste of time 😂
Unfortunately marketing works really well.🤣

#### SuperdutyTD

Unfortunately marketing works really well.🤣
Reminds me of when people wouldn't buy 1/3 pound burgers because they thought they were smaller than 1/4 pounders. 😅

#### kschachn

On the other hand also waiting for that study that shows lower filtering efficiency results in lower wear.

#### brianl703

Reminds me of when people wouldn't buy 1/3 pound burgers because they thought they were smaller than 1/4 pounders. 😅

Always thought that the solution for that was to call them 2/6 pound burgers..

#### Robert Scalchi

Quality cars are produced by companies who place importance on "Quality Assurance" (testing and re-testing and re-testing all the designs and parts, etc to find the bugs before production starts). That mentality is abscent from some Auto makers.
Absent from some? Yes. Intentional from others? Yes too. Remember? They profit from financing and short life cycles. Just like smartphones and software upgrades

#### SubieRubyRoo

Some people like cleaner oil more than others, and filter efficiency has nothing to do with if the filter will cause an engine related failure or not.
I don’t know anyone who ever liked a dirty lube over a clean one.

#### Bellavita

Hi,

I've been going through this filtration forum, trying to compile a list of oil filters that are rated at 99% Efficiency @ 20 microns.
Would anyone be able to supply a list, and maybe add a column on each row for whether the filter has synthetic media (as that should imply fast flow).
It would be very helpful to everyone on this forum.

FYI - I'm currently using Fram Ultra 99%+ Efficiency @ 20 microns with synthetic media for fast flow.
But am looking for alternatives.
Hi Bill7

I recently compiled a data analysis, along with excellent idea contributions from BITOG members,
of oil filters for my 2021 Subaru Forester. The list includes performance specs, how they're tested, if data is available, price and construction in the remarks area. The only one on the list that is advertised as all synthetic is the Purolator Boss. The data is about 1 month old so I've included the websites where the data was obtained. This will help you to get latest information in the event it has changed. Keep in mind that this list is for my Forester, there may be other suppliers out there for you application. Good shopping and feel free to ask questions!

#### kschachn

Hi Bill7

I recently compiled a data analysis, along with excellent idea contributions from BITOG members,
of oil filters for my 2021 Subaru Forester. The list includes performance specs, how they're tested, if data is available, price and construction in the remarks area. The only one on the list that is advertised as all synthetic is the Purolator Boss. The data is about 1 month old so I've included the websites where the data was obtained. This will help you to get latest information in the event it has changed. Keep in mind that this list is for my Forester, there may be other suppliers out there for you application. Good shopping and feel free to ask questions!
Perhaps, but the Fram Ultra is advertised as synthetic which it is. Just because the filter uses a non-synthetic support layer doesn't mean the main filtering layer isn't fully synthetic. The Boss' metal(?) support doesn't make it any less synthetic.

#### ZeeOSix

##### \$100 site donor 2022
The Boss' metal(?) support doesn't make it any less synthetic.
The Purolator Boss uses a nylon mesh backing that is bonded to the media.

#### kschachn

The Purolator Boss uses a nylon mesh backing that is bonded to the media.
Okay thanks. I wasn’t sure how that filter supported the media.

#### OVERKILL

##### \$100 Site Donor 2021
And of course actual results for "99%" can be quite different as Ascent showed us:

#### ZeeOSix

##### \$100 site donor 2022
And of course actual results for "99%" can be quite different as Ascent showed us:
A little added notation to see the "99%" particle size easier.

Replies
63
Views
7K
Replies
120
Views
25K
Replies
44
Views
4K
Replies
49
Views
7K
Replies
17
Views
2K