Originally Posted By: The_Eric
Originally Posted By: jsinton
Originally Posted By: gathermewool
How much oil is replenished during a filter change?
If you're not generating much in the way of contaminants and your goal is resource conservation, then wouldn't using a better filter for twice the interval or longer make more sense?
Many of us who do change our oil every 7-10k miles leave the filter for up to twice that that long (for my Honda - 6k interval for the Subie). In fact, if you change your oil filter every 3k miles you're tossing 5 filters away for every one I toss.
Yeah, I don't believe keeping a filter on for a long time is such a great idea. If you've ever owned a vacuum cleaner, a fish tank, changed a air con filter, etc. you can see the logic. It's important to keep oil pressure high. An oil filter might still work after 12k, but for sure you've lost oil pressure. So I don't believe the kool-aid about "high mileage" oil filters. You lose pressure, it's as simple as that.
You've taken a reasonably sound approach to this, but your knowledge is lacking when it comes to oil filters and TBN.
Excess TBN's floating around????
Also, running an oil filter longer will result in greater efficiency and lower solids- this I'm sure you know. What you seem to be missing is that the same amount of oil WILL pass through the filter, no matter it's state of loading. This is because the type of oil pump autos use is called positive displacement. They WILL push a set amount of oil through a given restriction, or restrictions (filter, oil galleries) no matter what. Your concern of LOWER oil pressure is unfounded. In fact, the greater the restriction, the GREATER the pressure (pressure is a measure of restriction). If a filter becomes so loaded that it can no longer filter or pass oil without self destructing, then it or engine (depending on design) will by-pass the filter media. This is set to happen on PSID (pressure differential or delta). Typically around 7-10 lbs. Member Jim Allen has some excellent info on this from an extended data logging session he did.
Ideally to conserve time and resources, you'd figure out how to run a filter to the point of by-pass, at which time, you'd replace it and top off the oil. By keeping unneeded filter changes to a minimum, you're also keeping wastes and energy consumption associated with manufacturing (from mining of raw ore to finished products) down.
Now the reality is that while your efforts are worthy of applause, they will not have a measurable impact unless a FAR greater percentage of the motoring public joins you.
Bypass filters are great, if you're lazy and your filter is clogged. But who wants unfiltered oil flowing through their engine? Look at it this way: If you had a vacuum cleaner with a bypass filter, would you want it to clean your house with it? I sure wouldn't. It would be blowing all that dust that I just tried to clean, would it not? And I don't believe the theory about oil pressure remaining the same whether the filter is clogged or not. Why? Just my experience with analog oil pressure gauges. Oil pressure is highest right after I change the filter. It's as simple as that. And what is wrong with too much TBNs? Well nothing so long as your motor is very clean. But if you try to dump oil with a lot of TBNs into an old motor with gunk, it could ruin your engine by loosening up gunk and clogging the lifters, so if you have an old motor with dino oil, stick with the dino, because synthetic has too much TBNs.
Originally Posted By: jsinton
Originally Posted By: gathermewool
How much oil is replenished during a filter change?
If you're not generating much in the way of contaminants and your goal is resource conservation, then wouldn't using a better filter for twice the interval or longer make more sense?
Many of us who do change our oil every 7-10k miles leave the filter for up to twice that that long (for my Honda - 6k interval for the Subie). In fact, if you change your oil filter every 3k miles you're tossing 5 filters away for every one I toss.
Yeah, I don't believe keeping a filter on for a long time is such a great idea. If you've ever owned a vacuum cleaner, a fish tank, changed a air con filter, etc. you can see the logic. It's important to keep oil pressure high. An oil filter might still work after 12k, but for sure you've lost oil pressure. So I don't believe the kool-aid about "high mileage" oil filters. You lose pressure, it's as simple as that.
You've taken a reasonably sound approach to this, but your knowledge is lacking when it comes to oil filters and TBN.
Excess TBN's floating around????
Also, running an oil filter longer will result in greater efficiency and lower solids- this I'm sure you know. What you seem to be missing is that the same amount of oil WILL pass through the filter, no matter it's state of loading. This is because the type of oil pump autos use is called positive displacement. They WILL push a set amount of oil through a given restriction, or restrictions (filter, oil galleries) no matter what. Your concern of LOWER oil pressure is unfounded. In fact, the greater the restriction, the GREATER the pressure (pressure is a measure of restriction). If a filter becomes so loaded that it can no longer filter or pass oil without self destructing, then it or engine (depending on design) will by-pass the filter media. This is set to happen on PSID (pressure differential or delta). Typically around 7-10 lbs. Member Jim Allen has some excellent info on this from an extended data logging session he did.
Ideally to conserve time and resources, you'd figure out how to run a filter to the point of by-pass, at which time, you'd replace it and top off the oil. By keeping unneeded filter changes to a minimum, you're also keeping wastes and energy consumption associated with manufacturing (from mining of raw ore to finished products) down.
Now the reality is that while your efforts are worthy of applause, they will not have a measurable impact unless a FAR greater percentage of the motoring public joins you.
Bypass filters are great, if you're lazy and your filter is clogged. But who wants unfiltered oil flowing through their engine? Look at it this way: If you had a vacuum cleaner with a bypass filter, would you want it to clean your house with it? I sure wouldn't. It would be blowing all that dust that I just tried to clean, would it not? And I don't believe the theory about oil pressure remaining the same whether the filter is clogged or not. Why? Just my experience with analog oil pressure gauges. Oil pressure is highest right after I change the filter. It's as simple as that. And what is wrong with too much TBNs? Well nothing so long as your motor is very clean. But if you try to dump oil with a lot of TBNs into an old motor with gunk, it could ruin your engine by loosening up gunk and clogging the lifters, so if you have an old motor with dino oil, stick with the dino, because synthetic has too much TBNs.