I was hoping to get away with keeping the stock oil pan but wasn't sure it was likely given it's tough to find dimensions online. I've cut a welded aluminum pans in the past so wasn't worried about the process, just not looking forward to it.
However, now it's pretty clear that I need to cut 1.75" off the pan to fit everything under the hood. This is way more than I was hoping for. Hood scoop is not an option since the bulge would be in a very awkward location.
I made some sketches of the stock pan, then the stock pan cut down 1.75," and then the cut pan with a wing added to the driver's side. The sketches show a left and right 1G turn and the oil line to keep constant volume. I know this is
WAY oversimplified with so many missing variables I can't even list them. However, it's an OK way to visualize the delta from pan to pan. Keep in mind the pan mating surface is tipped 30deg on BMW motors, the bottom of the pan is level.
Stock Pan turning left (pickup is the short line at the bottom):
Stock Pan turning right (forgot the pickup on this one):
Cut Pan turning left (with corresponding lower volume of oil):
Cut Pan turning right:
Winged cut pan turning left (wing volume included in oil volume but wing empty due to G force):
Winged cut pan turning right (whole wing volume full. This could be improved with a trap door):
I think the upshot of this is that I'm uncomfortable with any of these options. The depth of the pickup is just too low relative to stock. So, I'm starting to shop for used dry sump systems. We have a lot of experience at work trying to make marginal wet sumps work (better said, good wet sumps with crazy good tires) and it is one of the hardest things to do without learning by engine destruction.
Any thoughts are appreciated, I feel like I'm going overkill but I hate worrying about oil pressure. Also, there should be 5-10 hp available in drawing a high crankcase vacuum with a real dry sump.
Alex