Toilet paper oil filters? This is some kind of joke, right? Actually, a number of aftermarket auxiliary oil filters use toilet tissue rolls as their replaceable filter media. This type of unit has been around for about 50 years. While it may sound silly initially, the idea is based on a sound principle.
Such units are actually called bypass or secondary filters. They work by diverting a small portion of the engine’s oil flow, through an externally mounted canister containing an Ultra-fine, or “UF” filter element, and return the highly filtered oil to the engine’s oil sump.
The elements are sometimes made of string wound on a spool. Most are made of rolls of paper, which resemble toilet paper. These elements are actually made of fibers of a specific composition, wound at a controlled tension, and may even be chemically treated to help offset oxidation of the oil. The down side of these units is the cost, which can become prohibitive when used in the consumer realm.
Other units do, in fact, use toilet paper. It should be noted that some manufacturers advise against using such a material as a filter element, as toilet tissue is not high quality paper. They claim that the paper itself may contain damaging contaminants that may be released during operation, and since the paper is not of a dense construction, it can release fibers that themselves can be damaging contaminants. Others, however, claim no ill effect from using toilet tissue, emphasizing the fact that it is a readily available and very economical filter medium, and oil analysis has not indicated the presence of any unusual contaminants as a result of it’s use.
So, why is any of this important? Because extensive oil filter tests testing dating back to the mid-60’s has shown that particles in the oil as small as 5 microns, or .0002 inch, are responsible for a great deal of engine wear. Most full flow filters are not very efficient at capturing dirt smaller than 30 microns, and are almost incapable of capturing particles smaller than 10 microns. Enter the “toilet paper” oil filter. Whether you call them bypass filters, secondary filters, or toilet paper filters, the fact is most such units are capable of removing oil-borne particles in the range of 1 – 5 microns. This is possible because they have large media area and are not required to pass all of the oil flow at once.
Ana additional benefit to the toilet paper oil filter is the ability to hold not only particulate contaminants, but to remove water and fuel contamination from the oil. Due to the size and absorptive capability of the filter element, bypass filters have much greater ability to retain liquid contaminants. This is important, as the presence of water in motor oil is a major contributor to the development of sludge and acid, both of which are major causes of engine deterioration
Most consumer vehicles rely on the full-flow filter to remove larger dirt particles fro the oil, and addictives in the oil to hold the smaller particles in suspension. These additives are also relied on to neutralize acids and disperse sludge and related contaminants. Eventually, the combination of particulate and chemical contamination overcomes the capability of the oil to counteract them. This is why oil changes are required in order to maintain engine performance and achieve an acceptable engine service life. This ongoing maintenance costs money and creates additional environmental loads due to the need for disposal.
Adding a filter unit like this to your vehicle can go along way toward increasing engine life and drastically reducing the need for oil changes. Some users claim to have driven 100,000 miles and beyond without an oil change on their personal vehicles. Commercial vehicles, such as over-the-road semi trucks have been documented going in excess of 400,000 miles with out draining and refilling the oil. Oil samples have been analyzed by testing labs and shown that the oil was still in usable condition. This should be of interest to vehicle owners who use their vehicles for a lot of stop-and-go city driving, driving in extreme heat or cold, in very dusty conditions, or under heavy loads, such as towing. These uses accelerate oil contamination and engine wear. Such users stand to benefit the most from using bypass filtration on their vehicles.
The benefits of such an oil filtration system are numerous. So, don’t think that someone is joking when you hear them talking about toilet paper oil filters.
Oil Filter Tests
Oil filter tests determines the actual filtration performance of an oil filter. A quality oil filter has the ability to improve engine longevity, increase maintenance intervals, and result in substantial financial savings over the life of a vehicle. But when choosing an oil filter, how does a consumer determine which filter actually performs the best? For some insight, let’s examine how the industry tests oil filters.
All car oil filters have to undergo SAE (Society of Automotive Engineers) tests if they are to be considered in compliance with the vehicle manufacturer's specifications. There are two tests available for automobile engine oil filters. All automotive oil filters sold in the United States are only required to pass a simple single-pass test from the Society of Automotive Engineers (SAE) with only a simple pass or fail score. One of the original oil filtering tests was the SAE HS806 test. The SAE HS806 test uses a single-pass test, checking for contaminant holding capacity, size of contaminant particles trapped, and ability to maintain clean oil. The original nominal test was quite crude and simple in nature with just a single pass of dirty engine oil going through the filter. In order to pass the SAE HS806 test, just a minimum filtering threshold needed to be met.
Later, various amendments were issued to the SAE HS806 test. These included a multi-pass test that determines the filter’s expected filtering life, which was measured in hours. The oil filters expected filtering life was determined by subjecting the filter to a standard contaminate particle size carried in a given weight of motor oil at a constant flow rate, pressure and temperature. The test continued until the filtering media became clogged enough to raise the differential pressure drop across the oil filters intake and exit port to the predetermined level. After the oil filters filtering ability declined and fell under the standard level, the filter was then weighed and the gravimetric measurement of the filtered test oil was subtracted from the finishing weight, which resulted in the total weight of contaminant that the filter could effectively hold. The efficiency of the filter is determined only by weight through gravimetric measurement of the filtered test liquid. Typical numbers for paper filter elements are around 85% (single pass) and 80% (multi-pass).
Due to the above testing parameters, the life and efficiency test results generally include a time weight efficiency measurement, which is, was usually stated as a percentage, and total holding capacity stated in a unit of grams.
Due to the shortfalls in the HS806 filtering testing, the SAE decided to create a new an advanced optional filtering standard called J1858.
The SAE J1858 is a superior beta ratio test that is optional to the oil filter manufacturers that feel that the standard SAE HS806 test is too lax. The beta ratio test is defined as the ratio of the total number of particles upstream of the oil filter verse the total number of particles downstream of the oil filter for a predetermined determined particle size.
The new testing procedure is also no longer a simple one-pass test like the HS806 test. The J1858 test counts the size and quantity of the particles entering and leaving the oil filter and is a multiple pass test. Multiple pass testing is considered the most efficient way of testing oil filters, as it is similar to the operation of the oil filter on the vehicle. Multiple pass testing procedures have been recognized by SAE (SAE J1858), ISO (ISO 4548-12, engine lubricating oil and ISO16889, hydraulic or fuel), ANSI (American National Standards Institute) and NFPA (National Fluid Power Association).
The new test provides both gravimetric measurement and particle counting to measure both the micron filtering capacity of the oil filter as well as the total filtering capacity of the oil filter. Actual counts of contaminant particles by size are obtained every 10 minutes, both upstream (before the filter) and downstream (after the filter), for evaluation using lasers to detect the size and quantity of the particles entering and leaving the oil filter. This determines the beta ratio.
Using the beta ratio test, the filtering capacity of the oil filter with a beta rating of 85 at a 15 micron particle size will have a mean of 85 separate particles that are 15 microns in size upstream of the oil filter for every single 15 micron particle down stream of the oil filter. The flow rates through the oil filter can also very from 0.5 to 60 gallons per minuet. The change in flow rate of the oil through the filter is necessary in order to replicate the engines true operating conditions. These operating parameters can start from the initial cranking of the engine, which would result in a large spike in oil pressure with a low volume of oil flow, to full throttle, where the flow rate and pressure would be at there maximum.
From this data, filtration ratio and efficiency for each contaminant particle size can be determined as well as dust capacity and pressure loss as a function of time.
All filters must be tested with the J806 test, but the new J1858 is much more meaningful. Currently, the J1858 test is optional. Usually, the high-end filter manufacturers are the most anxious to display these numbers.
Most automotive oil filters state their efficiency rating in a micron filtering number. Microns are a linear measurement indicating length, or in relation to automotive oil filters, it indicates the length and width of various particle sizes. Micron ratings are some what of an arbitrary number as it only indicates the oil filters ability to remove contaminants at a particular particle size and not the efficiency or total contaminant holding capacity of the oil filter. What does the word micron mean? The word micron is another term for micrometer (1 millionth of a meter). A simple comparison is that a 25-micron particle is approximately 0.001 of an inch. Some linear equivalents are 1 inch is 25,400microns and 1 micron is .000039 inches.
Some comparative sizes are:
Diameter of average human hair 70 microns
Lower limit of visibility (naked eye) 40 microns
White blood cells 25 microns
Talcum powder 10 microns
Red blood cells 8 microns
Bacteria 2 microns
Carbon black 0.6 microns
Tobacco smoke 0.5 microns
Typical numbers for paper element filters are 40% efficiency at 10 microns, 60% at 20 microns, 93% at 30 microns, and 97% at 40 microns.
A filter that is marked or rated "10 micron" has some capability to capture particles as small as 10 micrometers. However, when you see a filter marked "10 micron", you do not know exactly what this means unless you also have a description of the test methods and standards used to determine the filter rating. The results from the different test methods may not be comparable as their methodology varies greatly.
Many automotive filtering companies state that their oil filters can filter down to 10 microns or 0.00033 of an inch, but at what percentage can they filter that size of a particle. Stating an oil filters micron rating without stating the filtering efficiency and capacity at that particle size is misleading. For example, all automotive oil filters will filter a 10-micron particle to some extent. Some cheaper designs will only filter one percent of all 10-micron particles in the engine oil, while others can filter out 75 percent of all 10 microns particles. The difference between a mediocre and superior oil filter design is that the poor design will only filter the 10 micron particle by chance, while the superior oil filter was designed to specifically filter 75 percent of all 10 micron particles.
The main advantage of the new SAE J1858 test is that the filtering ratio and efficiency for varying sizes of particles and the pressure drop across the filter as a function of time can be determined. Compared to the standard SAE HS806 test, the SAE J1858 test does a far better job in determining the total filtering capacity of the oil filter, actual filtering percentage values at various micron ratings, and the differential pressure capabilities. But, the J1858 test is by no means perfect.
First, the J1858 test was only an optional test that the majority of automotive oil filter makers did not use. Then, there are two basic testing options for companies that undergo the optional SAE J1858 test. First, the companies can have the oil filter name stated with their test results that are published by the SAE in their journals and or publish the filtering specifications in their advertisement. But, the manufactures can also simply state in their advertising that they passed the test, but not state the oil filter’s test results.
Another problem is that the test results were not required by the SAE to be published using the filters name, make and model. The oil filter manufactures can request that the filtering data be considered proprietary information, which results in no one but the manufacturer knowing the testing results. Unfortunately, keeping the test results proprietary is the most common approach used by the oil filter companies.
Again, this results in customers not knowing the filtering capacities of the each oil filter that passed the J1858 test, and only knowing that they met the minimum J1858 cut off point. This again limits the customer’s ability to determine whom makes the best automotive oil filter and which filter best suits their individual needs.
So, what is the bottom line? How does a consumer make an educated choice? You must do your homework and decide for yourself. Though accurate information on individual oil filter testing is difficult to obtain, perhaps one way to research the matter is through the filter manufacturers themselves, through their publications and websites. While each manufacturer will certainly extol the virtues of their own product, the better the product, the more likely the manufacturer is to disclose the details. If the oil filter testing information you want isn’t readily available, there is probably a reason; either it doesn’t exist, or the manufacturer isn’t proud of it.
All car oil filters have to undergo SAE (Society of Automotive Engineers) tests if they are to be considered in compliance with the vehicle manufacturer's specifications. There are two tests available for automobile engine oil filters. All automotive oil filters sold in the United States are only required to pass a simple single-pass test from the Society of Automotive Engineers (SAE) with only a simple pass or fail score. One of the original oil filtering tests was the SAE HS806 test. The SAE HS806 test uses a single-pass test, checking for contaminant holding capacity, size of contaminant particles trapped, and ability to maintain clean oil. The original nominal test was quite crude and simple in nature with just a single pass of dirty engine oil going through the filter. In order to pass the SAE HS806 test, just a minimum filtering threshold needed to be met.
Later, various amendments were issued to the SAE HS806 test. These included a multi-pass test that determines the filter’s expected filtering life, which was measured in hours. The oil filters expected filtering life was determined by subjecting the filter to a standard contaminate particle size carried in a given weight of motor oil at a constant flow rate, pressure and temperature. The test continued until the filtering media became clogged enough to raise the differential pressure drop across the oil filters intake and exit port to the predetermined level. After the oil filters filtering ability declined and fell under the standard level, the filter was then weighed and the gravimetric measurement of the filtered test oil was subtracted from the finishing weight, which resulted in the total weight of contaminant that the filter could effectively hold. The efficiency of the filter is determined only by weight through gravimetric measurement of the filtered test liquid. Typical numbers for paper filter elements are around 85% (single pass) and 80% (multi-pass).
Due to the above testing parameters, the life and efficiency test results generally include a time weight efficiency measurement, which is, was usually stated as a percentage, and total holding capacity stated in a unit of grams.
Due to the shortfalls in the HS806 filtering testing, the SAE decided to create a new an advanced optional filtering standard called J1858.
The SAE J1858 is a superior beta ratio test that is optional to the oil filter manufacturers that feel that the standard SAE HS806 test is too lax. The beta ratio test is defined as the ratio of the total number of particles upstream of the oil filter verse the total number of particles downstream of the oil filter for a predetermined determined particle size.
The new testing procedure is also no longer a simple one-pass test like the HS806 test. The J1858 test counts the size and quantity of the particles entering and leaving the oil filter and is a multiple pass test. Multiple pass testing is considered the most efficient way of testing oil filters, as it is similar to the operation of the oil filter on the vehicle. Multiple pass testing procedures have been recognized by SAE (SAE J1858), ISO (ISO 4548-12, engine lubricating oil and ISO16889, hydraulic or fuel), ANSI (American National Standards Institute) and NFPA (National Fluid Power Association).
The new test provides both gravimetric measurement and particle counting to measure both the micron filtering capacity of the oil filter as well as the total filtering capacity of the oil filter. Actual counts of contaminant particles by size are obtained every 10 minutes, both upstream (before the filter) and downstream (after the filter), for evaluation using lasers to detect the size and quantity of the particles entering and leaving the oil filter. This determines the beta ratio.
Using the beta ratio test, the filtering capacity of the oil filter with a beta rating of 85 at a 15 micron particle size will have a mean of 85 separate particles that are 15 microns in size upstream of the oil filter for every single 15 micron particle down stream of the oil filter. The flow rates through the oil filter can also very from 0.5 to 60 gallons per minuet. The change in flow rate of the oil through the filter is necessary in order to replicate the engines true operating conditions. These operating parameters can start from the initial cranking of the engine, which would result in a large spike in oil pressure with a low volume of oil flow, to full throttle, where the flow rate and pressure would be at there maximum.
From this data, filtration ratio and efficiency for each contaminant particle size can be determined as well as dust capacity and pressure loss as a function of time.
All filters must be tested with the J806 test, but the new J1858 is much more meaningful. Currently, the J1858 test is optional. Usually, the high-end filter manufacturers are the most anxious to display these numbers.
Most automotive oil filters state their efficiency rating in a micron filtering number. Microns are a linear measurement indicating length, or in relation to automotive oil filters, it indicates the length and width of various particle sizes. Micron ratings are some what of an arbitrary number as it only indicates the oil filters ability to remove contaminants at a particular particle size and not the efficiency or total contaminant holding capacity of the oil filter. What does the word micron mean? The word micron is another term for micrometer (1 millionth of a meter). A simple comparison is that a 25-micron particle is approximately 0.001 of an inch. Some linear equivalents are 1 inch is 25,400microns and 1 micron is .000039 inches.
Some comparative sizes are:
Diameter of average human hair 70 microns
Lower limit of visibility (naked eye) 40 microns
White blood cells 25 microns
Talcum powder 10 microns
Red blood cells 8 microns
Bacteria 2 microns
Carbon black 0.6 microns
Tobacco smoke 0.5 microns
Typical numbers for paper element filters are 40% efficiency at 10 microns, 60% at 20 microns, 93% at 30 microns, and 97% at 40 microns.
A filter that is marked or rated "10 micron" has some capability to capture particles as small as 10 micrometers. However, when you see a filter marked "10 micron", you do not know exactly what this means unless you also have a description of the test methods and standards used to determine the filter rating. The results from the different test methods may not be comparable as their methodology varies greatly.
Many automotive filtering companies state that their oil filters can filter down to 10 microns or 0.00033 of an inch, but at what percentage can they filter that size of a particle. Stating an oil filters micron rating without stating the filtering efficiency and capacity at that particle size is misleading. For example, all automotive oil filters will filter a 10-micron particle to some extent. Some cheaper designs will only filter one percent of all 10-micron particles in the engine oil, while others can filter out 75 percent of all 10 microns particles. The difference between a mediocre and superior oil filter design is that the poor design will only filter the 10 micron particle by chance, while the superior oil filter was designed to specifically filter 75 percent of all 10 micron particles.
The main advantage of the new SAE J1858 test is that the filtering ratio and efficiency for varying sizes of particles and the pressure drop across the filter as a function of time can be determined. Compared to the standard SAE HS806 test, the SAE J1858 test does a far better job in determining the total filtering capacity of the oil filter, actual filtering percentage values at various micron ratings, and the differential pressure capabilities. But, the J1858 test is by no means perfect.
First, the J1858 test was only an optional test that the majority of automotive oil filter makers did not use. Then, there are two basic testing options for companies that undergo the optional SAE J1858 test. First, the companies can have the oil filter name stated with their test results that are published by the SAE in their journals and or publish the filtering specifications in their advertisement. But, the manufactures can also simply state in their advertising that they passed the test, but not state the oil filter’s test results.
Another problem is that the test results were not required by the SAE to be published using the filters name, make and model. The oil filter manufactures can request that the filtering data be considered proprietary information, which results in no one but the manufacturer knowing the testing results. Unfortunately, keeping the test results proprietary is the most common approach used by the oil filter companies.
Again, this results in customers not knowing the filtering capacities of the each oil filter that passed the J1858 test, and only knowing that they met the minimum J1858 cut off point. This again limits the customer’s ability to determine whom makes the best automotive oil filter and which filter best suits their individual needs.
So, what is the bottom line? How does a consumer make an educated choice? You must do your homework and decide for yourself. Though accurate information on individual oil filter testing is difficult to obtain, perhaps one way to research the matter is through the filter manufacturers themselves, through their publications and websites. While each manufacturer will certainly extol the virtues of their own product, the better the product, the more likely the manufacturer is to disclose the details. If the oil filter testing information you want isn’t readily available, there is probably a reason; either it doesn’t exist, or the manufacturer isn’t proud of it.
Characteristics of Quality Oil Filters
The characteristics of a high quality oil filter are highly desirable, but not always externally visible. Most auto parts retailers offer a wide variety of oil filters, and aside from being different colors, they all look almost the same. A visual inspection can still reveal some important points, such as case construction, end cap design, and o-ring seal mounting. However, many of the most important factors that determine filter quality are internal, and their performance is only determined through laboratory testing. Still, some research will help you select the best quality filter for your application at the best price.
A good filter has a strong steel case to withstand the high oil pressure (60-80psi when cold), an anti-drainback valve that effectively prevents flow reversal while creating minimal restriction, a pressure relief valve with a positive seal, and a strong element and cap that can withstand the pressure and flow of oil without becoming damaged. The element media has to be able to strike an acceptable balance between dirt containment and flow restriction.
It should be noted that while most oil filters contain media in a steel canister that is threaded on to the engine, some automakers use a permanent canister that uses a disposable filter media cartridge that can be removed and replaced.
The typical spin-on filter has an end cap with a threaded center hole, surrounded by a group of smaller holes. Oil enters through the surrounding holes, passes through the filter media, and exits through the threaded center. The outer holes must be of sufficient quantity and size to allow unrestricted oil flow into the canister. The center return hole should be well formed and free of burrs or damaged threads. The end cap itself must be sturdy enough to resist flexing, which can create leakage when the unit is tightened. Most quality oil filters feature plated end caps to prevent rust before they are installed.
The surface of the end cap is sealed to the engine block using an o-ring gasket to prevent leakage. The o-ring should be solidly attached to the end cap. The quality of this o-ring can vary, with cheap filters using lower quality material, which can either soften or become brittle with age. Either condition can lead to seal failure, creating a leak at a critical point in the oiling system. If such a leak is severe enough, it can lead to engine damage or destruction due to loss of oil pressure and supply. Some high quality oil filters will use an improved seal material, such as Viton, which is more resistant to heat and oil exposure.
Most filters have an anti-drainback valve to prevent oil from draining backwards into the oil pan. Cheap filters, however, may have valves that fail to seal properly. When this happens, oil drains out of the filter when the engine isn’t running. Many engines will exhibit excess valvetrain noise at start-up until the filter fills up again and oil begins to circulate through the engine. This period of oil starvation contributes to unnecessary wear.
Most filters also have a pressure relief or bypass valve that will allow oil to flow past the filter element in the event that it becomes too clogged for the oil to flow through it. This prevents oil starvation, which will severely damage the engine. Similarly, a bypass valve is necessary to prevent bursting the element, possibly causing pieces of it and the debris it filtered to enter the engine, again causing serious damage. Also, when the oil is cold it may become very thick, and will tend to bypass the filter through the pressure relief valve because it cannot pass through the element until it warms up and thins out somewhat. If it did not do this, the filter element media would again be in danger of bursting.
The filter media is the part we usually pay the most attention to. The filter media is usually a cellulosic (paper) or a synthetic material, although different media, such as steel wool or cotton, have been used over the years. Paper media is used on inexpensive filters and works reasonably well. The paper is generally treated with some type of resin or coating to improve the performance of the media and help it withstand the rigors of the environment it operates in. The fibers are able to block particles down to a certain average size, while allowing the oil to pass through. On average, paper elements can trap about 97 percent of the 40 micron particles, 93 percent at 30 microns, 60 percent at 20 microns, and 40 percent at 10 microns.
Some manufacturers add other media, such as cotton, to the cellulose to improve its performance. High-end filters often use synthetic fiber media that has smaller passages to trap smaller particles, but can pass more fluid through it because it has a greater total number of passages. There is also media that is a hybrid of these two.
Then, there are units known as depth filters; as the oil passes deeper into the element, the smaller the passages get. This way, large particles are trapped toward the front surface of the element while small particles are stopped deeper in the element. This allows the filter to hold more debris before it becomes full.
The characteristics of a quality oil filter are not always obvious, the benefits to using a high quality filter are. And while it may take some research to determine which filters are built well, the extended engine life and reduced operating cost will pay you for your effort.
A good filter has a strong steel case to withstand the high oil pressure (60-80psi when cold), an anti-drainback valve that effectively prevents flow reversal while creating minimal restriction, a pressure relief valve with a positive seal, and a strong element and cap that can withstand the pressure and flow of oil without becoming damaged. The element media has to be able to strike an acceptable balance between dirt containment and flow restriction.
It should be noted that while most oil filters contain media in a steel canister that is threaded on to the engine, some automakers use a permanent canister that uses a disposable filter media cartridge that can be removed and replaced.
The typical spin-on filter has an end cap with a threaded center hole, surrounded by a group of smaller holes. Oil enters through the surrounding holes, passes through the filter media, and exits through the threaded center. The outer holes must be of sufficient quantity and size to allow unrestricted oil flow into the canister. The center return hole should be well formed and free of burrs or damaged threads. The end cap itself must be sturdy enough to resist flexing, which can create leakage when the unit is tightened. Most quality oil filters feature plated end caps to prevent rust before they are installed.
The surface of the end cap is sealed to the engine block using an o-ring gasket to prevent leakage. The o-ring should be solidly attached to the end cap. The quality of this o-ring can vary, with cheap filters using lower quality material, which can either soften or become brittle with age. Either condition can lead to seal failure, creating a leak at a critical point in the oiling system. If such a leak is severe enough, it can lead to engine damage or destruction due to loss of oil pressure and supply. Some high quality oil filters will use an improved seal material, such as Viton, which is more resistant to heat and oil exposure.
Most filters have an anti-drainback valve to prevent oil from draining backwards into the oil pan. Cheap filters, however, may have valves that fail to seal properly. When this happens, oil drains out of the filter when the engine isn’t running. Many engines will exhibit excess valvetrain noise at start-up until the filter fills up again and oil begins to circulate through the engine. This period of oil starvation contributes to unnecessary wear.
Most filters also have a pressure relief or bypass valve that will allow oil to flow past the filter element in the event that it becomes too clogged for the oil to flow through it. This prevents oil starvation, which will severely damage the engine. Similarly, a bypass valve is necessary to prevent bursting the element, possibly causing pieces of it and the debris it filtered to enter the engine, again causing serious damage. Also, when the oil is cold it may become very thick, and will tend to bypass the filter through the pressure relief valve because it cannot pass through the element until it warms up and thins out somewhat. If it did not do this, the filter element media would again be in danger of bursting.
The filter media is the part we usually pay the most attention to. The filter media is usually a cellulosic (paper) or a synthetic material, although different media, such as steel wool or cotton, have been used over the years. Paper media is used on inexpensive filters and works reasonably well. The paper is generally treated with some type of resin or coating to improve the performance of the media and help it withstand the rigors of the environment it operates in. The fibers are able to block particles down to a certain average size, while allowing the oil to pass through. On average, paper elements can trap about 97 percent of the 40 micron particles, 93 percent at 30 microns, 60 percent at 20 microns, and 40 percent at 10 microns.
Some manufacturers add other media, such as cotton, to the cellulose to improve its performance. High-end filters often use synthetic fiber media that has smaller passages to trap smaller particles, but can pass more fluid through it because it has a greater total number of passages. There is also media that is a hybrid of these two.
Then, there are units known as depth filters; as the oil passes deeper into the element, the smaller the passages get. This way, large particles are trapped toward the front surface of the element while small particles are stopped deeper in the element. This allows the filter to hold more debris before it becomes full.
The characteristics of a quality oil filter are not always obvious, the benefits to using a high quality filter are. And while it may take some research to determine which filters are built well, the extended engine life and reduced operating cost will pay you for your effort.
Subscribe to:
Posts (Atom)