Every engine needs oil delivered under pressure to bearings, cams, and squirters. How you store and pick up that oil is where wet and dry sumps diverge — and it matters more than most people realize once you start cornering hard or revving past 7,000 RPM.

Wet sump is what 95% of street cars run. Oil sits in the pan bolted to the bottom of the block. A pickup tube with a screen hangs into the oil, and a gear or gerotor pump driven off the crank or cam sucks oil up, pressurizes it, and sends it through the filter and galleries. Simple, cheap, self-contained.

Dry sump separates storage from the engine. The pan is shallow (an inch or two deep) and contains only scavenge pickups — usually 3 to 5 of them at low points. Multiple scavenge stages of an external pump suck oil and air out of the pan and dump it into a tall remote tank (usually 4-8 quarts, often mounted in the trunk or fender). A separate pressure stage pulls de-aerated oil from the tank bottom and feeds the engine.

Why bother? Three big wins:

• Oil starvation under g-loads. In a wet sump, sustained 1.2g cornering throws oil sideways and uncovers the pickup. The pump sucks air, bearings see zero pressure for milliseconds, and you wipe a rod bearing. Dry sumps have pickups everywhere — oil can't hide from all of them.
• Lower crankshaft. Shallow pan means you can drop the engine 2-4 inches in the chassis. Lower CG = better handling. This is why every Le Mans prototype and modern Corvette Z06/ZR1 uses dry sump.
• Less windage loss. In a wet sump, the spinning crank whips through oil mist and splash, costing 5-15 HP at high RPM. Dry sumps keep the crankcase nearly empty.

Rule of thumb for scavenge sizing: scavenge pump capacity should be 2.5 to 4 times pressure pump capacity. Why so much? You're pumping a frothy oil-air mixture, not liquid. A 4-stage pump flowing 15 GPM scavenge for a 4 GPM pressure side is typical for a road race V8.

Real-world example: The C8 Corvette Z06 (LT6 flat-plane V8) runs a factory dry sump with a 6-stage pump. GM engineers spec'd it because the LT6 sees sustained 1.4g lateral loads on track, and the flat-plane crank's high-RPM operation (8,600 RPM redline) makes windage losses brutal. A wet sump would either starve in Turn 6 at VIR or cost 20+ HP up top.

Downsides of dry sump: cost ($3-8k for a quality kit), complexity, external lines that can leak, and the belt-driven pump robs 2-5 HP — though you net positive from reduced windage.