Split71 - I would say my 35d does not use an unusual amount of oil. I'm usually down about a quart when an oil change is due. For me, that's been about a quart every 10-12,000 miles. So (just as for ZetaTre) the reason to think about doing this is not because of oil usage, but because of trying to limit carbon build up.
Dalecan - ZetaTre originally made a series of posts over on bimmerfest. As you will see, he uses the ID of lpcapital over there. His first post (
the link is here) is titled "Rather simple idea to reduce oil passing through crankcase?" Then a few months later he made a second post (
the link is here) that is titled "Improving on a "Rather simple idea (aka Version 2.0)." He summarized those two posts into the beginning of this post. Though the post here covers the highlights, it is very interesting to read the original posts and see how things evolved over time, with obviously a lot of thought and effort going into it.