Fram TG vs. XG Oil Filter for 5K mile / 6 month OCI ?

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Soot is an ages-old Diesel engine issue. As was said, centrifugal separators are how it is removed from those lubes. One could consider employing the same on a GDI engine. I seriously doubt the cost-benefit is there, and the soot particles are likely not the same general size range.

I am sympathetic to the concern about running filters for extended periods in a GDI soot-generator, but I think it is misplaced. Changing the oil clears the soot.

I think the advice to buy the cheap filter and change it often is exactly wrong. Run the best-filtering, highest-capacity filter of the 3 you’re considering, and run it for a minimum of two, and possibly as many as 3 or 4 of the short-ish OCIs you’ve planned. Use a particle count or similar if you want to verify, or just trust the filter company’s recommendations for miles. That captures both best filtration and lowest cost per mile. It’s also the lowest-waste option.
 

dnewton3

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Soot is a VERY misunderstood thing in ICEs.
Here's a great article/study.

In a nutshell, soot never gets large enough in any quantity to make any issues. It would have to grow (amalgamate) 100x in size just to become 4um, and that would be smaller than any FF filter would ever hope to capture. And that size enlargement does not happen in just mere miles.

The anti-agglomerate/dispersant part of the add-pack should be keeping soot from co-joining. At some point, way into a deep and long OCI, the soot might become a sizeable problem. Otherwise, it's nothing to worry about. The full flow filter will catch any anomally that might get to a size of concern, and the add-pack keeps the bulk of it from getting too large in the first place.

Gas or diesel, I would not worry about soot unless you're over 15k miles into your OCI. Otherwise, soot it moot. I say this because in all the UOAs I've seen, soot (insolubles) are RARELY ever called out as being intrustive, and there's ZERO correlation between the wear rates in those UOAs and the soot loading. This is true esentially because an OCI less than 15k miles just does not allow soot to grow large enough to matter in mass quantity.
 
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I they old days before DI no sweat now with DI there is no way I'm going to run a filter over six months.
I've run wire-backed Fram Ultra's in my Chevy AWD Equinox with a 2.5L DI L4 (a notorious pig with bad rings) for two and three OCI's. That change interval put them at typically 8 to 12K miles. I found they could handle those intervals -- even in Alaska's severe service environment.

Those double and triple change out extensions made them quite effective and affordable.
 
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Joined
Jan 16, 2017
Messages
1,404
Soot is a VERY misunderstood thing in ICEs.
Here's a great article/study.

In a nutshell, soot never gets large enough in any quantity to make any issues. It would have to grow (amalgamate) 100x in size just to become 4um, and that would be smaller than any FF filter would ever hope to capture. And that size enlargement does not happen in just mere miles.

The anti-agglomerate/dispersant part of the add-pack should be keeping soot from co-joining. At some point, way into a deep and long OCI, the soot might become a sizeable problem. Otherwise, it's nothing to worry about. The full flow filter will catch any anomally that might get to a size of concern, and the add-pack keeps the bulk of it from getting too large in the first place.

Gas or diesel, I would not worry about soot unless you're over 15k miles into your OCI. Otherwise, soot it moot. I say this because in all the UOAs I've seen, soot (insolubles) are RARELY ever called out as being intrustive, and there's ZERO correlation between the wear rates in those UOAs and the soot loading. This is true esentially because an OCI less than 15k miles just does not allow soot to grow large enough to matter in mass quantity.
Interesting bits I pulled from this article:
  • Various investigators [10,11] have shown that diesel soot build up in oil gives rise to increased engine wear rates; Gautam et al. [12] reported that wear increases with higher soot concentration.
  • Soot reduces the effectiveness of anti-wear additives and its effect on wear depends upon the characteristics of the particles and agglomerates of soot. Abrasive wear occurs and wear scar width closely matches the primary particle size [10].
  • Oil thickening was found to enhance timing chain elongation due to abrasive action of soot on pins and bushing [13].
  • Bardasz et al. [14] studied the influence of high number of engine cycles on lubricant oil and that of oil characteristics on engine wear, comparing direct injection and port fuel injection engines and finding increased wear for the first category.
  • At the macro scale, the GDI soot agglomerates are remarkably similar to agglomerates from light duty diesel engines as reported in the literature.
  • Conversely, the primary particles differ in nanostructure from a typical diesel soot particle. GDI primary particles are spherical in shape, with some irregularities.
It helped cement commonly held beliefs as presented on this website. :)
 
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* With a DI soot producing engine and a TG/XG Fram rated for 99% @ 20 microns , what is the affect of soot on / in such a oil filter ? Does it pass soot or filter soot ?
Soot is too small to filter with a full flow filter until it agglomerates . You should change the oil before that.
 
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I've run wire-backed Fram Ultra's in my Chevy AWD Equinox with a 2.5L DI L4 (a notorious pig with bad rings) for two and three OCI's. That change interval put them at typically 8 to 12K miles. I found they could handle those intervals -- even in Alaska's severe service environment.

Those double and triple change out extensions made them quite effective and affordable.
I'm not talking the filter failing I'm talking adding to your engines oil dilution problems.
 

dnewton3

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Interesting bits I pulled from this article:

... helped cement commonly held beliefs as presented on this website. :)
I would politely disagree and say that there are no "commonly held beliefs", because if you asked 100 BITOGers about soot, you're going to get 95 different answers. The five who don't answer are too busy posting photos of kittens licking dogs in G&OT ... but I digress ...

My point to linking the article was to illuminate to folks that soot is WAY, WAY smaller than they think when it starts out. Soot initialization and growth are simiar, but not the same, in diesel vs GDI engines. But one commonality is that soot starts out measured in nm (nano-meters). A nm is 1000x smaller than a um. Most engine clearances are senstive to particles 5um and larger. This is why BP filtration has a very effective meause of success; once the particles are large enough, they catch the particles before they can be damaging. But even the best BP filter is only measurably effective (absolute) at perhaps 2 or 3 um. Soot doesn't get anywhere close to that large until the OCI is very long. One could reasonably claim that the average size of a soot particle is around 40nm when it begins it's lifecycle; that's 100x smaller than 4um, and at 4um it still would not be large enough to be caught by a typical FF filter. The key concept to understand is that we should not be confusing soot size with soot quantity. The soot particle count will go up as the OCI matures, but the size of the soot particles is not going up proportionallly with the OCI. Only AFTER the add-pack is heavily compromised will the soot amalgamation rate exponentially escalate; that doesn happen in the typical "normal" OCI.

As I said previously, even out to 15k miles, I've seen no correlation between UOA wear data and soot loads. Without correlation, there can be no causation proven. The conclusion to make is that between the initially small soot size, and the excellent work of the add-pack, soot is being kept at bay in a typical OCI. (I define an extended OCI is one that goes out past 15k miles).

Let's not forget that soot is not the only wear-causing entity; other hard particles such as hard metals generated from asperity, and silica ingested or otherwise introduced into the engine, do damage also. Particulate loading includes soot, silica, hard metals and even softer insolubles such as oxidation byproducts. All these together combine to make "wear" happen.

There are several SAE studies that have shown good correlation between the UOA metal counts and the PC particulate loading. Whereas UOAs will only see the lower end of wear metals due to the limitations of spectral analysis, they do show a very good correlation to the particle counts. Think of UOAs not as reporting all wear, but reporting a sample of all wear; that's what UOAs are good at. And so it's reasonable to conclude that when the wear metal counts are low, the PC loading is not yet high enough to cause real damage; you cannot have high wear without evidence showing up in a UOA. (I'm excluding catastrophic wear, which typically isn't caught in a UOA because it happens way too fast for a sample to be taken and analyzed before doom occurs). If soot were a big concern, we'd see the evidence in a typical UOA, as generated by a continuing escalation of wear metals. But the VAST MAJORITY of UOAs don't show this. Typically the wear metal rates actually go DOWN as the OCI matures; this is a very common phenomenon. Hence, it is impossible to claim that the rising soot load is hurting the enginge, when there's no corresponding rise in wear metals. This is because the soot, though accumulating in quanity, it's not gaining in a size yet able to produce wear. The population of soot is growing, but not the size of each individual particle in a tangible manner. It is illogical to conclude that soot matters, when the wear-rates are going down as the soot population is going up.

It is true to say that soot can be very damaging, and many SAE studies have proven that. However, that is true ONLY IF THE OCI DURATION IS AT A POINT WHICH THE OIL IS OVERWHELMED. Most OCIs never get past 15k miles, hence the oil is not heavily compromised, and therefore the soot never becomes a problem large enough to affect wear.

My simple point is this:
Soot does not matter in a typical, normal OCI. Few BITOGers understand this fact, and the reasons behind why it doesn't matter.
 

ChrisD46

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Soot is an ages-old Diesel engine issue. As was said, centrifugal separators are how it is removed from those lubes. One could consider employing the same on a GDI engine. I seriously doubt the cost-benefit is there, and the soot particles are likely not the same general size range.

I am sympathetic to the concern about running filters for extended periods in a GDI soot-generator, but I think it is misplaced. Changing the oil clears the soot.

I think the advice to buy the cheap filter and change it often is exactly wrong. Run the best-filtering, highest-capacity filter of the 3 you’re considering, and run it for a minimum of two, and possibly as many as 3 or 4 of the short-ish OCIs you’ve planned. Use a particle count or similar if you want to verify, or just trust the filter company’s recommendations for miles. That captures both best filtration and lowest cost per mile. It’s also the lowest-waste option.
Good reply I believe makes sense for a GDI engine: If I run a Fram Tough Guard or Ultra for two or possibly three 4K ~ 5K mile / 6 month OCI's - then I have already got my money's worth out of the oil filter .
 
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I would politely disagree and say that there are no "commonly held beliefs", because if you asked 100 BITOGers about soot, you're going to get 95 different answers. The five who don't answer are too busy posting photos of kittens licking dogs in G&OT ... but I digress ...

My point to linking the article was to illuminate to folks that soot is WAY, WAY smaller than they think when it starts out. Soot initialization and growth are simiar, but not the same, in diesel vs GDI engines. But one commonality is that soot starts out measured in nm (nano-meters). A nm is 1000x smaller than a um. Most engine clearances are senstive to particles 5um and larger. This is why BP filtration has a very effective meause of success; once the particles are large enough, they catch the particles before they can be damaging. But even the best BP filter is only measurably effective (absolute) at perhaps 2 or 3 um. Soot doesn't get anywhere close to that large until the OCI is very long. One could reasonably claim that the average size of a soot particle is around 40nm when it begins it's lifecycle; that's 100x smaller than 4um, and at 4um it still would not be large enough to be caught by a typical FF filter. The key concept to understand is that we should not be confusing soot size with soot quantity. The soot particle count will go up as the OCI matures, but the size of the soot particles is not going up proportionallly with the OCI. Only AFTER the add-pack is heavily compromised will the soot amalgamation rate exponentially escalate; that doesn happen in the typical "normal" OCI.

As I said previously, even out to 15k miles, I've seen no correlation between UOA wear data and soot loads. Without correlation, there can be no causation proven. The conclusion to make is that between the initially small soot size, and the excellent work of the add-pack, soot is being kept at bay in a typical OCI. (I define an extended OCI is one that goes out past 15k miles).

Let's not forget that soot is not the only wear-causing entity; other hard particles such as hard metals generated from asperity, and silica ingested or otherwise introduced into the engine, do damage also. Particulate loading includes soot, silica, hard metals and even softer insolubles such as oxidation byproducts. All these together combine to make "wear" happen.

There are several SAE studies that have shown good correlation between the UOA metal counts and the PC particulate loading. Whereas UOAs will only see the lower end of wear metals due to the limitations of spectral analysis, they do show a very good correlation to the particle counts. Think of UOAs not as reporting all wear, but reporting a sample of all wear; that's what UOAs are good at. And so it's reasonable to conclude that when the wear metal counts are low, the PC loading is not yet high enough to cause real damage; you cannot have high wear without evidence showing up in a UOA. (I'm excluding catastrophic wear, which typically isn't caught in a UOA because it happens way too fast for a sample to be taken and analyzed before doom occurs). If soot were a big concern, we'd see the evidence in a typical UOA, as generated by a continuing escalation of wear metals. But the VAST MAJORITY of UOAs don't show this. Typically the wear metal rates actually go DOWN as the OCI matures; this is a very common phenomenon. Hence, it is impossible to claim that the rising soot load is hurting the enginge, when there's no corresponding rise in wear metals. This is because the soot, though accumulating in quantity, it's not gaining in a size yet able to produce wear. The population of soot is growing, but not the size of each individual particle in a tangible manner. It is illogical to conclude that soot matters, when the wear-rates are going down as the soot population is going up.

It is true to say that soot can be very damaging, and many SAE studies have proven that. However, that is true ONLY IF THE OCI DURATION IS AT A POINT WHICH THE OIL IS OVERWHELMED. Most OCIs never get past 15k miles, hence the oil is not heavily compromised, and therefore the soot never becomes a problem large enough to affect wear.

My simple point is this:
Soot does not matter in a typical, normal OCI. Few BITOGers understand this fact, and the reasons behind why it doesn't matter.
Thank you for the expounding illumination. I would have ranked soot as a wear leader in today's DI engines, despite its micrometer size. It travels freely throughout our engines -- unimpeded by filters. Yet, your past exhaustive research says otherwise. You're driving that home. Continue to do so. I'm a pedestrian here and am continually learning. Some day, perhaps "common beliefs" will sink in. ;) :)

And yes, I was fully aware of the large size difference. As radio and telecom engineer and manager, I've been working with micro (1x10-6 ), nano (1x10-9) and pico (1x10-12) capacitance conversions (measured in Farads) for decades. In electronics, microfarad and picofarad capacitors are hugely important, with picofarad capacitance having its place at higher frequencies. Units, their designations, and their math conversions seem to be a lost art to all but the studious nerds of the world.

Note: I'm not up on website superscript or subscript markup. I suppose it's not difficult.
 
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