Is there any reasoning that owners of cars using high viscosity motor oil, should stay away from low micron filters for fear that flow may be restricted or the may filter by-pass the media during cold starts ?
Low micron oil filters and high viscosity oil
- Thread starter Spitty
- Start date
Only if its extremely thick but i don't think it'll be the case since most will just bypass if there's too much pressure. May be the reason why k&n the makers of supposed high flow oil filters wont state any filtration numbers since i cant find any on their sight. Gives some fuel to have a conspiracy as to why they claim higher flow but don't seem to provide figures.
There's not a direct comparison between filtration efficiency and flow. Some high efficiency filters flow very well, especially ones with synthetic media.
As far as the viscosity goes, no doubt that higher viscosity oil will be more difficult to flow through the filter regardless of the media. This will lead to more bypass events than would be seen with a lower viscosity oil. You can install a remote mount oil filter setup, making use of a larger filter to increase the flow capacity, or you can use a filter known to flow very well such as a Wix XP or K&N. I personally wouldn't stress much about it as the difference wouldn't be too drastic between say a 30 and 40 grade at operating temp.
As far as the viscosity goes, no doubt that higher viscosity oil will be more difficult to flow through the filter regardless of the media. This will lead to more bypass events than would be seen with a lower viscosity oil. You can install a remote mount oil filter setup, making use of a larger filter to increase the flow capacity, or you can use a filter known to flow very well such as a Wix XP or K&N. I personally wouldn't stress much about it as the difference wouldn't be too drastic between say a 30 and 40 grade at operating temp.
Not for any standard motor oil viscosity like 20w50 or such.
Only time to worry about that would be in very cold start-ups with thicker (higher "W" rating) oils. The way to mitigate excessive delta-p across the filter and therefore filter bypassing is to keep the engine PRM low until the oil warms up. At operating temperature, there is no concern because the viscosity difference at 100C between 20 and 50 is very small.
The only time the oil flow volume is resticted is when the PD oil pump hits pressure relief. If you fired up an engine at -20F and revved it to 5000 RPM the oil filter would be in bypass and most likely the pump in pressure relief ... that's the kind of condtion you would have to be in to reduce oil flow to the engine.
We do not know when a filter goes to internal by-pass. My fear is that if a low micron filter were to go to by-pass mode more often than a regular, say 30 micron filter, does that possible wash from the dirty side negate any benefit of getting a low micron filter in the first place ?
Also would an engine requiring, say, 20w-50, typically have larger operational clearances that might better tolerate particulates ?
Also would an engine requiring, say, 20w-50, typically have larger operational clearances that might better tolerate particulates ?
If you're worried about it, then get an oil filter that is both efficient (if you want efficiency) and also flows very well. They do exist.
Just because an oil filter is inefficient doesn't automatically mean it is free flowing, or vice versa. A low efficiency filter could very well be restrictive, which is partially the reason it's inefficient due to sloughing off captured debris from the delta-p across the media.
Read this thread from this point.
Would you all like to see ISO 4548-12 Oil Filter Lab Testing Comparison, Efficiency & Capacity, Pressure vs Flow, Bubble Point, and Burst?
I have this as a “watched” thread, so if you do happen to start a new one, could you put a note or link in this one to direct followers to the new thread? Thanks!! Yes, no problem I can do that.
bobistheoilguy.com
Not necessarily. Many new engines like the Corvette spec 0W-40, and it's not because of loose engine clearances. Those engines are just as tight as any of them.
Thank you for that.
pity there were not more filters in the comparison.
pity there were not more filters in the comparison.
All the K&N range will do the job or you could run a fram racing filter with 94% efficiency at 20 micron which is likely better than the K&N's. I'm swapping over to the fram racing filter because they are about the same price as any decent filter in Australia. I run 50 or 60 grade in a modified turbo vehicle.
The filter goes into bypass when ever the differential pressure exceeds the approximate by pass valve rating. Starting the engine would be a great example. Yes all cold oil is much "thicker" that oil at the engines stabilized operating temps.
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