Replacement for Purolator Boss Oil Filters

Joined
May 29, 2024
Messages
10
Last year I spent a considerable amount of time investigating the best oil filter(s) for my vehicles, which range from a classic 1970 Chevy to a 2002 Honda CR-V. In the mix is a supercharged Ford Modular Motor making >700 fwhp. I was able to come to that conclusion based on YouTube videos, including Brand Ranks filtration, flow and capacity testing (see attached final ranking), along with Whip City Wrencher tear downs. While the Brand Ranks testing wasn't fully exhaustive, I felt like it was a pretty good representation of what was out there. Specifically, they actually tested filters and didn't just rely upon advertised specs. Based on that testing, the Purolator Boss seemed like an excellent choice, not the best in any given category, but among some of the the best in each category. So last year I changed to this filter when conducting my oil changes.

Earlier this year I saw conversations on BITOG about Purolator changing their efficiency spec, from 99% at 25 microns to 99% at 46 microns. I'm not sure what they changed about their product, but this is simply not acceptable to me. I contacted M&H and they confirmed; the 46 microns at 99% spec on their webpage is accurate. Unbelievable! I don't even know what spec the filters I put into my vehicles last year, and early this year meet.

Therefore I am looking for opinions and specs/data about the best balanced full flow oil filters might be. I'm not looking for the best at filtration, or the best in flow or capacity, but rather, those that might do a good job at balancing all specs. This might be a fools errand, but I wanted to ask in this community for what conclusions you all have come up with.

For my supercharged motor, so far I really like the Fram Racing oil filters, at 94% efficiency at 20 microns, which might be in the 96-98% efficiency at 25 microns, which is close to where the Purolator Boss used to be. I've torn an HP4 apart, and besides coming wrapped they have tons of pleats, and very sturdy construction. I pulled out the media and measure 340 in sq. of media, which is pretty amazing. It's made in China which is a negative, but given the overall robustness and construction, I am seriously considering using for at least my supercharged motor, which has a high volume/pressure oil pump.

Brand Ranking Oil Filter Testing - Final Ranking.webp


20250520_152827.webp


20250520_152925.webp


20250520_153441.webp


20250520_153525.webp


20250520_153740.webp


20250520_153835.webp


20250520_154422.webp
 
besides coming wrapped they have tons of pleats, and very sturdy construction. I pulled out the media and measure 340 in sq. of media, which is pretty amazing. It's made in China which is a negative, but given the overall robustness and construction, I am seriously considering using for at least my supercharged motor, which has a high volume/pressure oil pump.

I didn't know Fram had a source out of China but that filter you got looks great... better than their U.S. made so in that case I would use it.
 
I was able to come to that conclusion based on YouTube videos, including Brand Ranks filtration, flow and capacity testing (see attached final ranking)
The BR "efficiency" ranking doesn't correlate well with actual official ISO 4845-12 efficiency test data ranking for many of those same filters. So take it with a grain of salt. And it's just a ranking ... tells you nothing about what the actual efficiency is (ie, xx% @ yy microns).

For my supercharged motor, so far I really like the Fram Racing oil filters, at 94% efficiency at 20 microns, which might be in the 96-98% efficiency at 25 microns, which is close to where the Purolator Boss used to be.
I don't think the Purolator Boss ever was at 99% @ 20u as formally shown on Purolator's website for the PBL30001 model.

The Fram Racing filter is a decent choice for your engine because it's meant for engines like yours. The efficiency if decent and I'm betting is flows well (meaning relatively low dP vs flow).
 
The BR "efficiency" ranking doesn't correlate well with actual official ISO 4845-12 efficiency test data ranking for many of those same filters. So take it with a grain of salt. And it's just a ranking ... tells you nothing about what the actual efficiency is (ie, xx% @ yy microns).


I don't think the Purolator Boss ever was at 99% @ 20u as formally shown on Purolator's website for the PBL30001 model.

The Fram Racing filter is a decent choice for your engine because it's meant for engines like yours. The efficiency if decent and I'm betting is flows well (meaning relatively low dP vs flow).
Thanks; the BR videos do show particle count by size, and for the Purolator Boss filter the quantity of particles it passed were among the best they tested, but to your point, it's a very crude measurement...raw weight of standardized dust. BR never shows us the distribution of the dust they introduce into the system, and is the weigh scale they use calibrated, etc. Even so, I feel like their testing is a start, and much better than anything else I've seen available out there. My problem is oil filter manufacturers only show us what they want us to see. No way I can make an educated decision on filtering efficiency alone. This is what we all need, side by side calibrated testing.
 
carquest premium across the board. even in the built motor.
Honestly I'd never considered CarQuest brand products. To me, it's kind of like buying a Wal Mart SuperTech brand filter, but I'll have to investigate. Thanks for the input.
 
I didn't know Fram had a source out of China but that filter you got looks great... better than their U.S. made so in that case I would use it.
Yeah, when I watch tear down videos of Fram products, it's seems they are always manufactured in the US, so it was a surprise to me as well that their racing filter products were manufactured in China. But like I said, my tear down showed super impressive features, very hard to ignore. This may seem silly, but I really like an oil filter to come wrapped, which the Fram Racing products do. I can't tell you how many times I've ordered oil filters from wherever (see this problem with Summit Racing mostly), and the oil filters have come out of their packaging, and are rolling around inside the box by the time I receive it. When you are trying to filter particles smaller than the eye can see, I don't understand why more oil filter manufacturers don't wrap their products to ensure minute junk isn't distributed into the motor at first startup.
 
At this point I would say Mobil 1 Walmart or carquest premium AAP got my vote for everything that you love having the best of the best .
The Mobil 1 product seems to have performed pretty well on the BR videos, but I'll have to investigate the SuperTech...I've never considered. Thanks for the suggestions.
 
Premium Guard XL all the way. Any of the variants as well, like those mentioned above.
Thanks for the suggestion, I'd never heard of Premium Guard filters before. Looks like my application calls for a PG4631: https://www.pgfilters.com/product-c...G4631/1970-Chevrolet-K20+Suburban/Oil-Filter/

I could only look this up by application, not attributes like thread size, length, height, etc. I'm definitely not running a Chevy K20 Suburban, but our 1970 Chevelle and my build Ford 4V motor take the same filter (running a 13/16-16 oil filter relocation kit on my Mustang).

I like how Premium Guard has a spec page for this product, like Fram Racing, but few others do. A couple of things...I don't see that they publish a filtering spec, they just say 15-25 micron rating. Is this 99% at 25 microns, or ?? Second, their spec'd flow rate is 25lpm (6.6gpm) minimum. I'm sure this flow rating is fine for our 1970 Chevy, but for my built motor it's probably a little on the light rating as a minimum, where I reckon I'd need a 7.5-8gpm flow rating. I actually called Fram this week and asked them about the flow rating for the HP4. Surprisingly, they told me their didn't hadn't run a test on the HP4, but their website does say the racing series of filters run from 10-18gpm flow ratings, depending on model, so I think I should covered on this product: https://www.fram.com/fram-racing-oil-filter-spin-on-hp4
 
Honestly I'd never considered CarQuest brand products. To me, it's kind of like buying a Wal Mart SuperTech brand filter, but I'll have to investigate. Thanks for the input.
carquest premium/microgard selects are built by Premium guard and they’re the XL model. Silicone ADBV/base gasket, coil spring leaf spring, 99% @20um and an extremely thick can.

here is an example after 6k miles in industrial fleet service with tons of idling in texas summer.

*edited to reflect correct mileage, i have so many filter photos in my phone it’s hard to go back and select the correct one😂

IMG_0977.webp


IMG_0978.webp


IMG_0979.webp


IMG_0980.webp


IMG_0981.webp


IMG_0982.webp


IMG_0983.webp


IMG_0984.webp


IMG_0986.webp


IMG_0985.webp
 
Last edited:
Wow, thanks! Does seem like a super robust filter as well. I especially like the large flow holes in the inside tube, and opposed to the louver slots you see on most filters. Where do you get the efficiency rating? I did a Google AI search and came up with 96% multi-pass efficiency at 20 microns, which seems to come from Amazon. Still better than the Boss, but looking for a spec page or repository I can rely on.
 
Wow, thanks! Does seem like a super robust filter as well. I especially like the large flow holes in the inside tube, and opposed to the louver slots you see on most filters. Where do you get the efficiency rating? I did a Google AI search and came up with 96% multi-pass efficiency at 20 microns, which seems to come from Amazon. Still better than the Boss, but looking for a spec page or repository I can rely on.
advance auto specs
 
Thanks; the BR videos do show particle count by size, and for the Purolator Boss filter the quantity of particles it passed were among the best they tested, but to your point, it's a very crude measurement...raw weight of standardized dust. BR never shows us the distribution of the dust they introduce into the system, and is the weigh scale they use calibrated, etc. Even so, I feel like their testing is a start, and much better than anything else I've seen available out there. My problem is oil filter manufacturers only show us what they want us to see. No way I can make an educated decision on filtering efficiency alone. This is what we all need, side by side calibrated testing.
There has been a lot of water under the bridge about oil filters in this forum. There are theories why the BR testing should be taken with a grain of salt. For instance, the official spec sheet from Purolator/M+H shows the Boss to be 99% >46 microns, yet it shows as the best filter on BR's ranking. Doesn't correlate. The Boss also comes in relatively low in efficiency in this official ISO 4548-12 test conducted by "Ascent Filtration Testing", in an ISO 4845-12 certified lab. If you want to learn about official official testing of oil filters it might be worth your time to read this long thread.

Another theory that the Boss ranked high in BR's testing is because the filters with stamped leaf springs had internal leakage going on, as discussed in many threads. So those leaky filters therefore ranked lower then they should and their efficiency went down to the level of the Boss. Whatever is the cause or causes, the Boss looks to be the best filtering filter, but based on other official test efficiency info it shouldn't rank that high.

The only BR testing I reference is their dP vs flow tests which I feel is pretty accurate. It's hard to get dP vs flow info on filters. But the bottom line on dP vs flow testing is when you look at the whole group of filters compared to each other, their flow performance difference typically isn't enough to worry about on an engine with a PD oil pump.

 
Last edited:
Honestly I'd never considered CarQuest brand products. To me, it's kind of like buying a Wal Mart SuperTech brand filter, but I'll have to investigate. Thanks for the input.
There is lots of info over the last year or so about these filters, and many others similar branded under the PGI umbrella. These PGI varients are all about the same, and have become a well liked filter option now that the Fram Ultra and Titanium have went down the tubes somewhat, and other Champ Labs filters have been getting leaf springs stamped in the ruffles factory.
 
Last edited:
The Mobil 1 product seems to have performed pretty well on the BR videos, but I'll have to investigate the SuperTech...I've never considered. Thanks for the suggestions.
It's not the new Mobil 1 under Highline Warren ... it's the old M+H made Mobil 1. The efficiency of that old Mobil 1 was 99% @ 30u if I recall correctly. The new Mobil 1 is suppose to be 99% @ 20u per what Highline Warren told me on the phone.
 
Back
Top Bottom