dnewton3
Staff member
Originally Posted by ZeeOSix
Originally Posted by Davejam
Yeah, as particles build up on a filter the filtration efficiency will increase.
Pressure drop will increase and therefore flow decrease, but as long as a filter is designed for extended use you will be ok.
So yes, wear should decrease.
Pushing things beyond filter/vehicle recommendations is at your own risk. But if you know what you're doing you'll be fine and perhaps better off.
Oil filters and air filters behave differently when they start loading up and the delta-p really starts to increase. Oil filters experience way more delta-p than air filters.
Studies show that some oil filters can start sloughing off captured particulate as the delta-p becomes higher and higher from debris loading (see graph below). So in that case, the filter is actually becoming less efficient as it loads up. A filter would have to be very good at retaining captured debris and become more efficient as the delta-p becomes higher.
I wouldn't run a filter much past the rated use indicated by the manufacturer unless it was on a very clean engine. As far as the OP's use ... 25K kilometers is still within Fram's rating.
And just because the delta-p becomes higher doesn't mean you're losing oil flow. Oiling systems use a positive displacement oil pump, so if the filter becomes a bit more restrictive the oil pump still forces the same volume of oil through it. Engine oiling systems are not like a water system in your house where a clogged filter will reduce the flow out of the water faucet.
Zee - when you get a chance can you please provide a link to the study/article that produced that chart? Is it an SAE study, or what? I'd like to get a copy so I can read the entire item.
Originally Posted by Davejam
Yeah, as particles build up on a filter the filtration efficiency will increase.
Pressure drop will increase and therefore flow decrease, but as long as a filter is designed for extended use you will be ok.
So yes, wear should decrease.
Pushing things beyond filter/vehicle recommendations is at your own risk. But if you know what you're doing you'll be fine and perhaps better off.
Oil filters and air filters behave differently when they start loading up and the delta-p really starts to increase. Oil filters experience way more delta-p than air filters.
Studies show that some oil filters can start sloughing off captured particulate as the delta-p becomes higher and higher from debris loading (see graph below). So in that case, the filter is actually becoming less efficient as it loads up. A filter would have to be very good at retaining captured debris and become more efficient as the delta-p becomes higher.
I wouldn't run a filter much past the rated use indicated by the manufacturer unless it was on a very clean engine. As far as the OP's use ... 25K kilometers is still within Fram's rating.
And just because the delta-p becomes higher doesn't mean you're losing oil flow. Oiling systems use a positive displacement oil pump, so if the filter becomes a bit more restrictive the oil pump still forces the same volume of oil through it. Engine oiling systems are not like a water system in your house where a clogged filter will reduce the flow out of the water faucet.
Zee - when you get a chance can you please provide a link to the study/article that produced that chart? Is it an SAE study, or what? I'd like to get a copy so I can read the entire item.