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Dry Sump

Car culture term

Dry Sump
Photo: Arnero / Wikimedia Commons · Public domain

What is Dry Sump?

An engine lubrication system that stores oil in a separate external tank rather than in a pan below the engine, allowing lower engine mounting, better oil control under cornering, and improved reliability under sustained hard driving.

A dry sump lubrication system removes oil from the engine rapidly using scavenge pumps and stores it in a separate external reservoir rather than in a pan beneath the crankshaft. The opposite, a wet sump, uses a conventional oil pan attached directly below the engine where oil pools by gravity between uses of the pressure pump. Dry sumps require additional pumps (multiple scavenge stages plus a pressure pump), lines, and a remote reservoir, making them more complex and expensive.

The advantages of dry sump are significant for performance use. First, oil starvation under hard cornering or braking is eliminated; in a wet sump, sustained lateral g-forces can splash oil away from the pump pickup, starving the engine momentarily. Second, the engine can be mounted lower (no deep pan below the crank), lowering the center of gravity. Third, crankcase windage (the power-robbing turbulence of the crank and rods spinning through oil mist in the pan) is reduced because the crank runs in a near-dry environment.

Dry sumps are standard in endurance racing, Formula 1, high-performance Porsches (the 911 GT3 and GT3 RS use dry sump as factory equipment), and some extreme sports cars. The Chevrolet LS7 in the C6 Z06 Corvette uses a factory dry sump. For track day or time attack builds where sustained high-g driving is expected, dry sump conversions are a worthwhile reliability upgrade.

Related terms

Naturally aspiratedTime attackTrack dayForged pistonsConnecting rodsHeader

Frequently asked questions

Why do race cars use dry sump?
Sustained cornering forces in a wet sump can push oil away from the pump pickup, causing momentary oil starvation and bearing damage. In a street car this rarely happens because cornering loads and durations are modest. In a track or race car sustaining 1.5-plus g in corners for extended periods, a wet sump is a reliability risk. Dry sump eliminates the problem entirely.
Can I convert my engine to dry sump?
Dry sump conversions exist for many popular performance platforms (LS engines, Subaru EJ, Honda K-series, BMW S54). The conversion requires a different oil pan, external reservoir, lines, and a multi-stage scavenge/pressure pump. It is an involved modification costing $3,000-$8,000 or more in parts and labor, typically reserved for dedicated track or time attack builds.
Is a dry sump worth it for street use?
For most street driving, no. A quality wet sump with a baffled pan (which reduces oil slosh) and a properly maintained oil level is sufficient. Dry sump complexity and cost is only justified when sustained high-g driving creates actual oil starvation issues, or when the lower engine mount height is a packaging or center-of-gravity priority.
What Porsche models use dry sump?
The 911 GT3, GT3 RS, and GT2 RS use factory dry sump systems. The Carrera models use a wet sump. The GT3's dry sump is part of its motorsport-derived engineering package, contributing to its ability to sustain full-throttle circuit laps without oil starvation issues.
Does a dry sump add power?
Modestly. Eliminating crankcase windage (the turbulence from the crank spinning in an oil-misted wet sump pan) can free up a small amount of power, typically 5-15 horsepower on a high-revving engine. The bigger benefit is reliability and the ability to mount the engine lower. Power gain is a secondary benefit, not the primary motivation.
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