Fram Ultra Synthetic: Flow Restriction, Bypass Setting, and Fine Filtration

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Jun 6, 2020
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I'm contemplating installing a Fram Ultra Synthetic (XG) filter. Fram specifies a shorter filter for my application (different model number in the PH series), but this XG filter has the same threads and a similar bypass setting.

1. Are Fram XG filters restrictive to flow? Some have suggested the high efficiency rating leads to flow restriction, while others say the synthetic media makes it easy-flowing.

2. Is it a problem that the bypass rating of the Fram XG is slightly higher than that of the OEM filter I plan to replace? Is this problem mitigated or exacerbated by the Fram XG's flow properties.

3. As the Fram XG filter is designed for a long OCI, are there any drawbacks (besides the price) to using it for short OCIs? Someone suggested that it may sacrifice fine filtration at the expense of high capacity, but I've seen other reports to the contrary.
 
I have run Fram XG series for the last 12 years, almost exclusively. From 2K OCI to 17K OCI, and never had any problems with it. This is only a personal experience, but you will find tons of posts on this board speaking of their quality. Just run them in you car and sleep well.
 
In real life we will never see any differences with the choice of oil filters Over the owner ship unless there is a catastrophic failure then a major brand will be the best at covering the costs. The Air filter is the most important filter and yes other will regurgitate some white paper they read but I worked most of my life in fleet maintenance..
 
Originally Posted by CT8
In real life we will never see any differences with the choice of oil filters Over the owner ship unless there is a catastrophic failure then a major brand will be the best at covering the costs. The Air filter is the most important filter and yes other will regurgitate some white paper they read but I worked most of my life in fleet maintenance..

Well said.
 
Originally Posted by kschachn
Today seems to be the day for oil filter flow posts.

1. No.
2. No, no.
3. No.

"Flow" is not a concern in a passenger car oil filter.


+1
 
Originally Posted by kschachn
"Flow" is not a concern in a passenger car oil filter.
Why not? Would it be a concern in smaller 4-cycle engines?
 
Originally Posted by viscous
Originally Posted by kschachn
"Flow" is not a concern in a passenger car oil filter.
Why not? Would it be a concern in smaller 4-cycle engines?



It's not a concern... The positive displacement pump will only pull but so much oil through the oil filter... And the pressure difference across the filter media is so very small it will be no where near enough to be a concern.
 
^^^ Exactly

Only thing to be concerned about with oil filter restriction is, when the oil is hot, that either the oil filter goes into bypass at high RPM, or the oil pump hits pressure relief at high RPM. The former will allow oil to not be filtered, and the latter will slightly cut the flow volume of oil going to the engine.

When the oil if cold, it's possible to do both those things if you rev the engine high. The "fix" is to let the oil warm up all the way before going crazy with engine revs.
 
Originally Posted by kschachn
Today seems to be the day for oil filter flow posts.

1. No.
2. No, no.
3. No.

"Flow" is not a concern in a passenger car oil filter.



Agreed. So technically any other motor with a larger filter then Honda Should be ok. See next paragraph. So flow is not the issue. Of course myself with Hyundai's, I will take the Hail Mary "hope" that larger base plate holes in the Titanium will help the limited oiling problem with some Hyundai's. That may stop a remote chance of possible foam, because of the very small holes in only the Hyundai Fram filters, including the only Fram filter I will use, the Ultra and Titanium. Fleeting hope, I know. Ha Ha.

A Honda V6/all Honda 4 cylinders/except S2000 has a thimble sized oil filter. Could be said to be the smallest or second smallest spin on filter in modern automobile use. Honda S2000 sports car with it's 9,000 rpm redline, and just a hair larger sized thimble sized filter then the V6/4 cylinder filter. Yet Honda have one of the most reliable and high mileage motor on earth. So yes, flow is not an issue as you said.

.
 
Originally Posted by viscous
I'm contemplating installing a Fram Ultra Synthetic (XG) filter. Fram specifies a shorter filter for my application (different model number in the PH series), but this XG filter has the same threads and a similar bypass setting.

1. Are Fram XG filters restrictive to flow? Some have suggested the high efficiency rating leads to flow restriction, while others say the synthetic media makes it easy-flowing.

2. Is it a problem that the bypass rating of the Fram XG is slightly higher than that of the OEM filter I plan to replace? Is this problem mitigated or exacerbated by the Fram XG's flow properties.

3. As the Fram XG filter is designed for a long OCI, are there any drawbacks (besides the price) to using it for short OCIs? Someone suggested that it may sacrifice fine filtration at the expense of high capacity, but I've seen other reports to the contrary.


1. Yes, all oil filters are restrictive to flow.
In a brand new Fram Ultra it isn't a problem, and the two ply structure helps thwart excessive early restriction. Any filter as it is loaded restricts more until eventually it no longer filters. But during restriction, smaller pores in the clogged media, or "pipes" increase pressure across them, and this "increased dp" maintains the same flow. So inspect your element if you are worried about restriction. Flow will be the same always and nearly instantaneous, so a clogged filter can quickly open the oil pump relief valve, which reduces flow.

2. Yes, but only if you have an engine that uses a variable oil pump which requires a specific bypass pressure. Bypass pressure ratings are sort of iffy, they don't often give a range, but Fram does and you can assume the single rating is in the middle of the range they give. And no, the Fram flows fine until like any filter, it is plugged up.

3. No drawbacks at all except price . The two layers give it higher capacity, The inner finer layer clogs slower because the outer coarser layer is dong the heavy lifting with large particles while still maintaining low flow restriction.

I hope some explanation helps rather than single word answers and all I said is best effort, my opinion, basis.

cheers3.gif
 
Originally Posted by Farnsworth
Originally Posted by viscous
2. Is it a problem that the bypass rating of the Fram XG is slightly higher than that of the OEM filter I plan to replace? Is this problem mitigated or exacerbated by the Fram XG's flow properties.

2. Yes, but only if you have an engine that uses a variable oil pump which requires a specific bypass pressure. Bypass pressure ratings are sort of iffy, they don't often give a range, but Fram does and you can assume the single rating is in the middle of the range they give. And no, the Fram flows fine until like any filter, it is plugged up.


Variable volume PD oil pumps put out less oil volume at lower RPM because the engine doesn't need as much oil volume to properly lubricate it. And variable volume oil pumps typically don't put out as much oil volume over the RPM range as an "old fashioned" non-variable PD oil pump because engineers are always trying to reduce the oil volume flow to gain that extra 0.01 MPG, and still provide adequate oil flow for proper lubrication.

So if an oiling system has a variable output pump, it doesn't dictate what the filter's bypass valve is going to be set at. A bypass valve setting is dependent on the filter's flow performance, and what the expected max oil viscosity and flow rates are expected. One filter can be specified for hundreds of different engines, so the bypass valve setting is not specified specially for each application.
 
ZeeOSix,

Before my account is deleted, I want to ask aren't PD oil pumps variable flow with engine rpm? The amount of oil flowed is dependent on unit time, with lower speed the unit time is reduced.

I've appreciated your fact-based posts with your knowledge and background, not resorting to personal attacks on those trying to learn more. Thanks.
 
Originally Posted by Farnsworth
Yes, but only if you have an engine that uses a variable oil pump which requires a specific bypass pressure.
Which types of engines have this? Is this feature common only to certain categories of engines?
Originally Posted by Farnsworth
I hope some explanation helps rather than single word answers and all I said is best effort, my opinion, basis.
Yes, good info. Thanks.
Originally Posted by ZeeOSix
A bypass valve setting is dependent on the filter's flow performance, and what the expected max oil viscosity and flow rates are expected.
So if an OEM filter for a particular application has a certain bypass setting, an alternative filter could match the OEM's performance specifications without necessarily having the same bypass setting, because the alternative filter's media could have different flow properties? The easier-flowing the media is, the higher the bypass setting can be, such that as media flow restriction approaches "no restriction", bypass requirement approaches "no bypass valve necessary"?
 
Originally Posted by LubricatusObsess
ZeeOSix,

Before my account is deleted, I want to ask aren't PD oil pumps variable flow with engine rpm? The amount of oil flowed is dependent on unit time, with lower speed the unit time is reduced.


All PD oil pumps (even non-variable output pumps) are variable flow because as the engine RPM goes up so does the flow rate - basically in a linear fashion up to the pump's pressure relief setting.

However, with a variable output PD oil pump, the ECU will change the flow output while at a constant engine RPM. An example would be say with a non-variable oil pump it would put out 3 GPM at 2500 RPM, but with a variable output pump on the same engine it may put out 2 GPM to reduce the small amount of HP that it takes to pump the oil. The whole reason variable flow PD pumps exist it so save a very small amount of fuel.
 
Originally Posted by LubricatusObsess
... Before my account is deleted, I want to ask aren't PD oil pumps variable flow with engine rpm? The amount of oil flowed is dependent on unit time, with lower speed the unit time is reduced....
Positive displacement means fixed volume pumped per engine revolution, therefore flow rate varies directly proportional to engine speed (regardless of pressure, hypothetically).
 
Originally Posted by viscous
Originally Posted by ZeeOSix
A bypass valve setting is dependent on the filter's flow performance, and what the expected max oil viscosity and flow rates are expected.
So if an OEM filter for a particular application has a certain bypass setting, an alternative filter could match the OEM's performance specifications without necessarily having the same bypass setting, because the alternative filter's media could have different flow properties?


Yes, that's why different brands of oil filters for the same exact engine might have a slight difference in the filter's bypass valve setting.

Originally Posted by viscous
The easier-flowing the media is, the higher the bypass setting can be, such that as media flow restriction approaches "no restriction", bypass requirement approaches "no bypass valve necessary"?


Opposite in the part in red ... the more free flowing the filter, the lower the bypass setting can be. If a filter was very flow restrictive, the bypass valve setting would have to be set higher so the filter didn't go into bypass all the time.

If a filter had zero delta-p because of flow there wouldn't even be a need for a bypass valve. The last part of your comment is correct.
 
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