I had lunch with a BMW mechanic and asked him that question. The answer was a surprise.

My engine burns oil. It’s a V10 and there’s a lot going on in there and a lot of pressure. It’s common knowledge that you keep an extra quart of 10W-60 around as every two months you’ll need it. I assumed the more I mash the gas pedal the more oil it’ll consume but I have noticed I haven needed any lately. I ran 7 autocross laps full-out last Saturday and didn’t lose any. (It’s measured electronically to the 1/10th and it has a delay between checks that would have hit by now.) I also have taken it out on the mountain roads a bit and let it off the leash and still nothing. It’s full and staying full.

In June it was drinking oil on the regular.

Last December I didn’t lose a drop.

That’s the pattern.

Rather than give you the answer he gave me I’m going to leave this out there for folks to ponder. Many of us are on our commute home or about to be so it’ll give you something to noodle on, and I’ll post the answer I got from my mechanic friend in a few hours.

Not that it matters but I’m in CA, use 91 octane all year (93 is what BMW recommends) aside from when I might get 100 octane at a track or outside of CA. I also have the same driving habits all year.