Originally Posted by JCL

On BITOG they are claimed to be made by Champion Labs, who make filters for a lot of different companies. Some of those companies are AC, STP, Car&Driver, Deutsch, Champ, Bosch, Lubrifiner, Mopar, Kleener, TRD, VW, and Mobil. Champion list Royal Purple as one of the brands they make. And they have a factory in Albion, Illinois. So it looks like that paid advertisement was actually filmed at a Champion factory.

This is all moot, as you can't use a Royal Purple filter anyway, since they don't make cartridge filters like BMW uses.

Royal Purple claim their membranes are better, but why would you believe that? Isn't that what most advertising says? They aren't comparing their filter to BMW, they are comparing it to some unknown other filter. And if it filters more, it will generally plug up faster. On a spin-on filter, what happens then is the bypass valve opens, and the filter stops filtering, as all the oil bypasses it. Specs should include filtering performance, and capacity, and be a result of tests run to SAE standards.

BMW doesn't publish any specs for their filters, so any aftermarket filter is of an unknown quality compared to OE BMW. Even filters made by BMW suppliers (Mahle, Mann) can have different filter media and quality in the same size filter compared to an OE BMW filter.

This isn't to say that all of these aftermarket filters are bad, some may be just fine. Some may be better than OE. And since these models are out of warranty, owners can buy whatever they like without fear of BMW pointing to a filter as a cause of engine failure. I just think it is interesting that Royal Purple can come out with purple oil filters at a premium price, made by a third party who makes a wide range of filters, and people line up to buy them. Shows the power of marketing.