Quote:
Originally Posted by trask768
I own a small industrial filter company, and I just switched all the oil filters in my small fleet of company cars over to a longer oil filter.
The reason that surface plays such a big role is because it lowers the pressure drop across the filter. And yes, this pressure drop can be substantial (I think up to 20 psi when dirty - same as the bypass valve setting). Not only does this reduce the amount of work needed to pump oil through the filter
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VERY helpful, great information. I have a question about your conclusion regarding losses associated with a relatively more restrictive filter:
If my bypass valve pops at 20psi, and while running at hiway speeds my engine sees about 40psi, then my oil bypassing the filter most of the time, right? At idle, my oil pressure might be 15psi, bypass valve closed, thus only filtering my oil while I am at a stop light, right? If that's right, then the only time I could possibly be using less power to turn my oil pump is when the pump is putting out less than 20psi, so I only save fuel under low loading situations, do I have that right?
With more filtering area you should be able to go more miles between filter changes if you wanted to, and reduce your chances of a clogged filter like you say. The old O-Berg aftermarket filters used to have a pressure sensor option, 'tattle-tale' they called it, to notify the driver of a greater than 15psi pressure differential across the filter: If the car builder wired it up right, when the separate filter idiot light comes on, it's time to clean the filter. Those were ok filters, just not enough square inches. Most racers I know have gotten away from that and gone to a System 1 or similar pleated stainless steel screen type filter. With or without bypass is still debated.