Attention: TDR Forum Junkies 
The Importance of Using a Paper Air Filter
(cut and paste from latest Cummins "Turbo Diesel News")
Maintaining a clean air filter is very important for the life of your engine. What does dust do to an engine? Let’s follow the air as it enters the intake. First, the turbo gets hit with the dust – the blades are spinning as fast as 150,000 rpm, and hitting just a small amount of dust at that speed can actually remove material from the turbo blades. Next, the piston rings and engine bore take a beating because the dust acts as an abrasive material, wearing away those two sliding surfaces. Dust can then find its way into the oil by getting past the rings against the bores of the engine. With the oil filter able to hold only so much dirt before plugging and then bypassing, eventually the rest of the engine bearings suffer.
The factory-pleated paper air filter is a critical element of the air system, and it ensures that clean air is delivered to the engine to be used during the combustion process. It is designed to balance both the flow across the filter and filtered surface area, to ensure that your engine runs at peak performance. For example, a driver who uses a particularly dusty route may have 100g of dirt ingested into his air filter. The factory filter at 99. 9 percent efficiency will have allowed 0. 1g of dirt through the filter and into the engine. An aftermarket cotton-gauze filter or oiled cotton-gauze filter on the other hand typically runs around 97 percent efficient. That 3 percent difference can have a big effect on the life of your engine.
At 97 percent efficiency, 3g equal 30 times more dirt sent through to the engine! This multiplication is true for the life of the filter – the oiled cotton-gauze filter will always let 30 times more dirt through.
While cotton-gauze-style filters have a lower restriction when they are clean, there are two fundamental issues with them, the first being dust-holding capacity. Due to the thickness of the material used, these filters have very low dust-holding capacity. The way in which they hold the dust means they plug up quickly, and just a small amount of dust makes the restriction increase substantially.
However, the biggest issue with cotton-gauze filters is their filtration efficiency. As mentioned earlier, restriction is based on a combination of the filtration level and the surface area. The surface area of aftermarket filters is typically much smaller than that of the standard filters, so they manage to offer lower restriction on a clean filter by having much bigger gaps in the material, leading to much lower filtration efficiency.
Oiled cotton-gauze filters are generally cleaned and re-oiled at certain mileage intervals. However, the oil used in these filters is hard on the mass air flow (MAF) sensor and surrounding components. The oil tends to come off these filters as a fine mist and coat the intake systems. This leads to incorrect readings from the already-sensitive MAF sensor.
While all diesel engines are vulnerable to dust, using the recommended factory pleated paper air filter does the best job protecting your engine while balancing flow and restriction. The paper material leads to higher filtration efficiency, which will ultimately lead to a cleaner, stronger Cummins Turbo Diesel.
(cut and paste from latest Cummins "Turbo Diesel News")
Maintaining a clean air filter is very important for the life of your engine. What does dust do to an engine? Let’s follow the air as it enters the intake. First, the turbo gets hit with the dust – the blades are spinning as fast as 150,000 rpm, and hitting just a small amount of dust at that speed can actually remove material from the turbo blades. Next, the piston rings and engine bore take a beating because the dust acts as an abrasive material, wearing away those two sliding surfaces. Dust can then find its way into the oil by getting past the rings against the bores of the engine. With the oil filter able to hold only so much dirt before plugging and then bypassing, eventually the rest of the engine bearings suffer.
The factory-pleated paper air filter is a critical element of the air system, and it ensures that clean air is delivered to the engine to be used during the combustion process. It is designed to balance both the flow across the filter and filtered surface area, to ensure that your engine runs at peak performance. For example, a driver who uses a particularly dusty route may have 100g of dirt ingested into his air filter. The factory filter at 99. 9 percent efficiency will have allowed 0. 1g of dirt through the filter and into the engine. An aftermarket cotton-gauze filter or oiled cotton-gauze filter on the other hand typically runs around 97 percent efficient. That 3 percent difference can have a big effect on the life of your engine.
At 97 percent efficiency, 3g equal 30 times more dirt sent through to the engine! This multiplication is true for the life of the filter – the oiled cotton-gauze filter will always let 30 times more dirt through.
Now, let’s compare and contrast your factory pleated paper air filter with some common aftermarket filters. While cotton-gauze-style filters have a lower restriction when they are clean, there are two fundamental issues with them, the first being dust-holding capacity. Due to the thickness of the material used, these filters have very low dust-holding capacity. The way in which they hold the dust means they plug up quickly, and just a small amount of dust makes the restriction increase substantially.
However, the biggest issue with cotton-gauze filters is their filtration efficiency. As mentioned earlier, restriction is based on a combination of the filtration level and the surface area. The surface area of aftermarket filters is typically much smaller than that of the standard filters, so they manage to offer lower restriction on a clean filter by having much bigger gaps in the material, leading to much lower filtration efficiency.
Oiled cotton-gauze filters are generally cleaned and re-oiled at certain mileage intervals. However, the oil used in these filters is hard on the mass air flow (MAF) sensor and surrounding components. The oil tends to come off these filters as a fine mist and coat the intake systems. This leads to incorrect readings from the already-sensitive MAF sensor.
While all diesel engines are vulnerable to dust, using the recommended factory pleated paper air filter does the best job protecting your engine while balancing flow and restriction. The paper material leads to higher filtration efficiency, which will ultimately lead to a cleaner, stronger Cummins Turbo Diesel.
