Skipping oil filter change
- Thread starter Nuclear_42
- Start date
By all means if you know your oil is severely contaminated and running a cheap filter replace both.
But spend a little more on a better filter, and it wont risk coming apart every oil change or not filtering well, and it will go a year. 1 cup of oil residual in a filter , much more than that through out the motor that you will never get out.
But yeah if you change oil every six months, and filter every year, life aint too bad.
But spend a little more on a better filter, and it wont risk coming apart every oil change or not filtering well, and it will go a year. 1 cup of oil residual in a filter , much more than that through out the motor that you will never get out.
But yeah if you change oil every six months, and filter every year, life aint too bad.
Isn’t the filter easily accessible. I wouldn’t be spending money on amsoil and filters with their stickers on it. Mobil 1 EP or pennzoil ultra platinum and filter really wouldn’t matter much just change it every oc. The oe subie filters are nothing special.
I still have a tough time believing those Subaru engines actually flow that much oil volume in real use. 60 L/min is 15.85 GPM, which is 63.4 quarts/min (1.06 qt/sec). If the sump was 5 quarts, then at that flow rate it means the sump is exchanged every 5.3 seconds. Pretty hard to believe that's actually happening, and if so the level in the sump would be dangerously low and risk of sucking air. Besides, who drives around at length at near redline unless you're on a race track. How do these engines fair on the race track ... any cases of engines blowing up because they suck air from low sump levels with the pump pushing 15.85 GPM?
The Amsoil filter is $2-3 cheaper than the fram endurance and about $1 cheaper than Mobil 1 filter. Both Amsoil and fram appear to be made by the same company
I’m pretty sure the Amsoil filter is about as good as it gets aside from a Fram endurance. Why would you call the Amsoil a cheap filter. Doesn’t seem to be of cheap quality.
It's difficult to compare filters based on UOAs. The reason is that filtration hardly makes a difference to wear rates in normal conditions, when wear rates and oil contamination are low. In these conditions I'd expect the Amsoil filter to do a better job despite the bypassing, but these aren't the conditions where filtration is important.
Filtration becomes really important when wear rates are abnormally high. When this happens, the wear metal particles will be much larger than normal, and the vast majority of abrasive wear can be caused by the larger particles. If the Amsoil filter is bypassing 30% of the oil flow, it's allowing 30 times more 40+ micron particles through than the 99% efficient Wix.
If you look at enough photos of cut open oil filters, you'll find examples of filters that contain sludge, chunks of carbon, RTV, large metal shavings, mystery materials, etc. You don't want this stuff circulating through your engine. Chances are your engine will live a long life regardless of your oil filter choice, but you could get unlucky.
I wouldn’t recommend Mobil 1 filters they’re ok but not worth the coin. I would go with the wix protec pxl57055 or the wix 57055. Both filters available through rock auto and will easily ride your oci’s. As you mentioned fuel dilution is your culprit not filtration.The Amsoil filter is $2-3 cheaper than the fram endurance and about $1 cheaper than Mobil 1 filter. Both Amsoil and fram appear to be made by the same company
The Boss PBL14615 isn't what I'd call a "high efficiency" filter. What do you mean the test didn't seem to be based on that filter model, when it was the Spec Sheet for that filter model?
Purolator's website claims 99% @ 25u based o PBL30001. But the official Spec Sheet shows it to be 99% >46u. Every M+H Spec Sheet I've seen posted in this forum have shown other smaller Boss models to also be 99% >46u. Why doesn't Purolator's website reflect the official Spec Sheet data for PBL30001? There is a big difference in efficiency between 99% @ 25u vs >46u.
I can't believe that the Boss that Brand Ranks tested was as efficient as the Ultra. Something was going on with the testing IMO that skewed results.
UOAs like what Blackstone uses only measures wear particles that are 5u and smaller. Most filters won't catch most of those particles, but a high efficiency filter that's 99% @20 will catch more than a less efficient filter. Motorking posted a few times that the OG Ultra was 80% @ 5u, and looking at Ascent's test data I can believe that. A particle count of UOAs in real use can show the difference in oil cleanliness between high efficiency filter and ones not so efficient. I've posted UOA particle count data taken from the UOA forum on this site, and it shows how the filter efficiency can effect the oil cleanliness.
Most engine wear studies say that it's particles smaller that 20 microns that do the most wear. That's why you want a filter as efficient as possible, especially if doing longer OCIs. The longer the OCI, the more important the oil filter efficiency becomes.
A lot of Subaru models are known for oil starvation on track. With the BRZ with the new FA24 engine the oil pressure can drop by 30 psi when going around right hand corners on track, and rod bearing failures are common on tracked cars. The old turbo EJ engines had similar issues. Larger sumps with baffling were pretty much required for reliable track use.
I believe it was you who showed me this in another thread:
If you look at the particle sizes for the Advanced Failure Mode for example, they skew much larger than when wear is normal. Most of the particles are still under 10 micron by particle count, but if you were to look at it in terms of total particle mass instead of particle count, almost all of the mass is from larger particles, since the particle mass scales with the cube of the diameter.
In the study I posted a while back with unfiltered oil, wear rates were only a bit lower for particles larger than 20 microns compared to 10-20 micron, when compared by equal mass of dust. Since almost all particle mass is from large particles during advanced wear, we could expect almost all of the wear will be caused by large particles in these conditions.
This is gold.
That figure basically shows that once wear from particulate starts getting above the "normal" realm, that 3-body wear from already existing particulate can start increasing the wear particulate concentration ... essentially a wear snowball effect. Of course a good oil filter should help prevent the 3-body wear snowball factor for the most part.I believe it was you who showed me this in another thread:
If you look at the particle sizes for the Advanced Failure Mode for example, they skew much larger than when wear is normal. Most of the particles are still under 10 micron by particle count, but if you were to look at it in terms of total particle mass instead of particle count, almost all of the mass is from larger particles, since the particle mass scales with the cube of the diameter.
In the study I posted a while back with unfiltered oil, wear rates were only a bit lower for particles larger than 20 microns compared to 10-20 micron, when compared by equal mass of dust. Since almost all particle mass is from large particles during advanced wear, we could expect almost all of the wear will be caused by large particles in these conditions.
In the "Benign" wear realm per that figure, most of the particulate is less than 1 micron. Not sure how accurate a Blackstone type of UOA is at measuring wear particles of 1u or less (?). If not very accurate below 1u, then the sliver of visible data in a standard UOA is even smaller. This figure also shows why a Blackstone type UOA that can not accurately see particulate over ~5u is virtually blind to any major engine wear issues going on unless you have a lot of UOA history on a specific engine. This is a good reason to cut open oil filters and look for visible wear metal particles that are too large for a UOA to detect. With lots of UOA history, you can still only look at a small sliver of wear particle size in the oil (5u or less). You would have to get near the Advanced and Catastrophic wear realms to see a significant up-tick in the 5u and less particle range over a history of UOAs on the same engine. You could actually have what look like a decent UOA based on one or two UOAs, but there could be crazy wear going on and visible particles in the oil filter.
I would think that wear rate is proportional to the number of wear particles and the size of them, and not the mass factor of those particles. The figure y-axis is number of particles per 10 mL, which are the same basic units of a standard particle count except they are typically units of number of particles per 1 mL.
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Patman
Staff member
You do realize that every time you change your oil there is still probably a good half to a full quart of old oil left behind anyways. You can never get 100% of the oil out just by pulling the drain plug. Lots of oil gets trapped in the heads, oil passages, etc.
. lol
I’ve left oil filter on for 3 OCI’s before without issues.
Yes that’s correct however my personal issue isn’t about the oil that’s left behind, it’s what’s trapped in that used filter. New oil with the detergent package being at its best can loosen the trapped contaminants. Then they are in the clean oil. Why risk degrading the whole oil change trying to save $8?
