Oil issues: Dry Sump, Accusump for road racing?

[Zach34]

...the oil being pulled out of the pan is being replaced by new oil coming in from the tank> OEM Pump> into the engine.

Unless you're in a long sweeping turn and some/most of the oil is collecting in the valve cover and not falling onto the pan where the scavenge pick-ups are. I think that's why we have to run a vacuum regulator, like the Cosworth setup, and I think that's why Chad had strange things happen when he sealed his motor up. I envision the scavenge pump operation being sort of analagous to trying to suck the last bit of milkshake from the bottom of the cup with a straw - you're mostly pulling air with small drops of liquid unevenly mixed in. It sort of has to be that way, because otherwise oil is filling up the crankcase and would quickly drown the crankshaft.

I speculate different motors are going to get different vacuum with the same DS scavenge pumps. I have an 11mm oil pump, but my engine was built by Element with looser clearances than Chad's OEM-clearance motor. That means that, hopefully, I don't get the overheating issues Chad had with the 11mm pump, which we now understand due to his heroic troubleshooting efforts. However, that also means I'm going to flow more oil through the engine, possibly at a slightly different pressure, which means the scavenge pumps will have more oil to pick up, which will impact their vacuum-producing ability. Lots of variables. I think a vacuum gauge and log is going to be worthwhile.

That's cool I have the exact same plan as you for the DS system, but you're way ahead of me. My job is going to shut down my progress for a few weeks coming up, too, as it has for most of the year. I'm interested to see your pan! I have access to a CNC mill here, so I'm probably going to design/build my own mainly as a way to learn the mill. I had tentatively planned on patterning the pan design off of the Cosworth one.