Hive mind on Mazda Miata filter selection.

[Ishmael]

I have purchased a new 2025 Mazda Miata with the 2.0 Skyactive G 4 2026 Subaru Outback with the non turbo 4 cylinder engine. I guess being retired give me more time to go down various rabbit holes, and the Mazda Subaru lube system offers a couple.

Everyone is aware that Mazda Subaru has a higher OFPB setting than the industry standard. I have never designed an engine in my life so I will blindly accept the Mazda Subaru engine folks have a reason.
I plan on doing 5K oil changes. I will be using the Purolator One filter as it has the specified oil bypass pressure. I will also be running Castrol Edge 0w-20.
From what I have seen, the Purolator One does a better job at filtering but as a result has higher PD across the filter. I have no idea the fluid volume the oil pump would put out at higher RPM's but could see it bumping up against the PD and going into filter bypass.
The Purolator Boss has less PD but does not filter as well. It's not a likely to hit the bypass pressure setting as easily as the One but will be allowing more of the finer particles through.

So, do I go with the One and just accept that it will go into bypass more frequently but when it does the bypassing fluid is cleaner than what the Boss may be doing on a regular basis?

Of do I just need to chill and not chase rabbits?

OK, just realized that the higher than normal bypass is actually on my wife's new Subaru....this rabbit hole too too many turns.

Need more coffee.

 

[BrendanC]

you spin a carquest premium 84356 on it and call it a day.

 

[ZeeOSix]

From what I have seen, the Purolator One does a better job at filtering but as a result has higher PD across the filter. I have no idea the fluid volume the oil pump would put out at higher RPM's but could see it bumping up against the PD and going into filter bypass.
The Purolator Boss has less PD but does not filter as well.

I will be using the Purolator One filter as it has the specified oil bypass pressure. I will also be running Castrol Edge 0w-20.

Where are you coming up with the dP vs flow of those filters with hot 0W-20 oil flowing through them? And what's the bypass valve setting on the Purolator ONE?

 

[Ishmael]

Where are you coming up with the dP vs flow of those filters with hot 0W-20 oil flowing through them? And what's the bypass valve setting on the Purolator ONE?

The valve setting for both was listed on a side by side comparison of the two Purolator filters I was looking at. The PD is based on test documents provided by Mann and Hummel on Boss and One filters that were not specific to whichever application was running through my mind at the moment. BITOG

 

[Ishmael]

you spin a carquest premium 84356 on it and call it a day.

Yeah, kicking around here I see that and the Microguard from O'Reilly's seem like quality items at a good price.

 

[BrendanC]

Yeah, kicking around here I see that and the Microguard from O'Reilly's seem like quality items at a good price.

microgard select is more expensive than the carquest premium. same OEM supplier of Premium Guard.

 

[EvoMan]

microgard select is more expensive than the carquest premium. same OEM supplier of Premium Guard.

In my area they are both the same price: $9.99.

 

[SC Maintenance]

In my area they are both the same price: $9.99.

Carquest Premium order online for 15% off if you buy $35.00 (which is 5). Free shipping.

If it matters to you. Either works.

 

[twX]

Purolator's recommendation for the Outback is the PL14615. If your goal is low restriction, you don't want to use it. It's a very small filter and only has around half the filter media of an OEM filter. It also has the smallest inlet holes of any oil filter out there.

I measured the cracking pressure of its bypass valve to be 29 psi, which, IMO, is a bit too high even for most Subaru engines.

If you can fit a wider filter, I'd recommend the PL14459. This model is now made in South Korea, and compared to the PL14615 it has better build quality, twice the amount of media, and much larger inlet holes. The 12-15 psi bypass setting is high enough. Another good option is the Pentius XL PLXL3593A.

 

[ARCOgraphite]

Ahh, the last of the wagon style. That is a smooth cruiser. We have owned many Subarus over the past 35 years from a Justy to an SVX.

O.E. service part Tokyo Roki. And something other than Castrol Edge.

I would spend more time figuring out how to disable the automatic braking and lane keeping and auto start-stop. That junk almost crashed me a few times by slamming on the brakes with no hazard with and a line cars right on my back bumper.

 

[ZeeOSix]

The valve setting for both was listed on a side by side comparison of the two Purolator filters I was looking at. The PD is based on test documents provided by Mann and Hummel on Boss and One filters that were not specific to whichever application was running through my mind at the moment. BITOG

They all show the bypass to crack open at 107 kPa (15.5 PSI) ... which is less than the Subaru OEM filter. Note that the spec sheet for the PL14610 shows "10.7" kPa, but that's obviously a misprint and should be 107 kPa.

The dP on the spec sheet is at the "nominal flow rate", which is 24 l/min (6.6 GPM) or 11.35 l/min (3.0 GPM) for the PL14610 only. The viscosity of the oil is 25 mm^/sec = 25 cSt in each case, which is about 3 times thicker than a 0W-20 at 200F.

With hot oil, the dP vs flow is going to be pretty low similar to this graph with was date collected by Purolator. Just don't hammer the throttle and do high RPM until the oil has warmed up. With hot xW-20 oil, the whole curve will shift downward on the graph. Pick points off the data sheets and see where they land on this graph for a rough comparison.

 

[Ishmael]

When using the Purolator look up page it gives three filters to fit the 2.5 naturally aspirated Subaru engine.
The Boss (PBL14615)
The One (PL14615)
The Red (L14615)
When you select the "Product Details" on any of these it states the BPVS is 20-30 pounds.

So now that I have finally figured out which car I currently am fixated on, my question is which of these filter is the better choice for a 5K oil change interval?
That makes the assumption the filtering element in these

 

[Ishmael]

you spin a carquest premium 84356 on it and call it a day.

Ok, another rabbit hole, but this one has a nice ending.
I looked up the Carquest Premium for the Subaru and it provided me with the 84712 number.
It seems to have the same filtering ability but does have the higher bypass pressure called for by Subaru.

 

[ZeeOSix]

When using the Purolator look up page it gives three filters to fit the 2.5 naturally aspirated Subaru engine.
The Boss (PBL14615)
The One (PL14615)
The Red (L14615)
When you select the "Product Details" on any of these it states the BPVS is 20-30 pounds.

So now that I have finally figured out which car I currently am fixated on, my question is which of these filter is the better choice for a 5K oil change interval?
That makes the assumption the filtering element in these

The ONE will have rhe best filtration efficiency of the Purolators. The Carquest Premium you found would be as good or better than the ONE.