What Is a Dry Sump Oil System?

A dry sump oil system is an engine lubrication design that stores oil in a separate tank and uses multiple pumps—one to pressurize oil and others to “scavenge” it from the engine—ensuring consistent oil pressure, improved reliability under high g-forces, and better packaging than a conventional wet sump pan. It’s widely used in motorsport, aviation, and high-performance road cars to prevent oil starvation and reduce power-robbing windage.

How a Dry Sump System Works

At its core, a dry sump decouples oil storage from the oil pan, relying on a dedicated pressure pump and one or more scavenge stages. The following step-by-step sequence outlines the typical flow of oil in a dry sump setup.

1. The pressure pump draws de-aerated oil from an external reservoir (tank).
2. Oil is sent under pressure through galleries to bearings, camshafts, and valvetrain components.
3. After lubricating and cooling parts, oil drains into low spots of the crankcase, heads, and timing covers.

4. Scavenge pumps pull aerated oil and blow-by gases from these areas, minimizing oil pooling and windage.
5. The scavenge flow passes through an air‑oil separator and often a cooler before returning to the tank.
6. Inside the tank, internal baffles and de-foaming features separate air from oil so the pressure pump receives a steady, bubble-free supply.

Together, these stages maintain stable oil pressure and reduce aeration, even during hard acceleration, cornering, braking, or extreme altitude and temperature conditions.

Key Components

Dry sump systems combine several purpose-built parts to manage oil supply, scavenging, and de-aeration. Below are the primary components and what they do.

• Pressure pump: Feeds filtered, de-aerated oil to the engine at a controlled pressure.
• Scavenge pump(s): Extract oil and vapors from the crankcase, heads, and timing areas; often multiple stages.
• External reservoir (tank): Stores oil; includes baffles, an air‑oil separator section, and level/temperature monitoring.
• Oil cooler: Reduces oil temperature, commonly placed in the scavenge return or pressure side.
• Filters and strainers: Full‑flow pressure filter plus scavenge-side screens to protect pumps and engine.
• Hoses and fittings: High‑temperature, high‑pressure lines connecting pumps, tank, cooler, and engine.
• Check, relief, and thermostatic valves: Prevent drain-back, regulate pressure, and manage warm-up flow.
• Drive mechanism: Belt-, gear-, or chain-driven pump assembly powered by the engine.
• Vent and catch system: Manages crankcase gases, preventing pressure buildup and oil loss through breathing.

Each component works in a closed loop to deliver reliable lubrication, manage heat, and limit aeration across a wide range of operating conditions.

Why It’s Used

Automakers and race teams choose dry sump lubrication for its performance, reliability, and packaging advantages. Here are the most cited benefits.

• Oil control under high g-forces: Prevents starvation in long sweepers, hard braking, and high-speed elevation changes.
• Consistent pressure and temperature: De-aeration and volume capacity stabilize lubrication and cooling.
• Reduced windage losses: Lower crankcase oil levels cut drag on the rotating assembly, freeing horsepower.
• Lower engine placement: A shallow pan allows the engine to sit lower for a better center of gravity.
• Improved crankcase vacuum: Scavenge stages can create slight vacuum, reducing blow-by and oil leaks.
• Greater oil capacity: Larger reservoirs enhance thermal management and service intervals in racing.

These strengths translate into longer engine life at the limit, improved lap-time consistency, and more flexible vehicle packaging.

Trade-offs and Challenges

Dry sump systems are not without costs and complexities. The following drawbacks are typically weighed against the performance gains.

• Higher cost and complexity: Extra pumps, tank, lines, and controls add expense and assembly time.
• Weight and packaging: Although the pan can be shallower, the tank and lines require space and mounting solutions.
• Maintenance demands: More fittings, hoses, and filters mean more inspection points and potential leak paths.
• Service procedures: Priming after oil changes, specific oil‑level checks, and temperature considerations are critical.
• Failure modes: A loose belt, collapsed hose, or aeration issue can quickly escalate if not monitored.

For most daily drivers, a modern baffled wet sump is sufficient; dry sump shines when consistent lubrication and performance margins are paramount.

Where You’ll Find It

Dry sump lubrication appears wherever oil control is mission-critical or performance-focused. Examples span competitive racing, aviation, and select road vehicles.

• Motorsport: Formula 1, endurance racing (WEC/IMSA), GT cars, rally, and top-tier drift and time-attack builds.
• Aviation: Many Lycoming and Continental piston aircraft engines use dry sump systems for reliability and packaging.
• High-performance road cars: Chevrolet Corvette C8 (all trims), various AMG V8s (e.g., M178), Ferrari V8/V12 models, and many Porsche 911 variants that employ an integrated form of dry-sump lubrication.
• Motorcycles: Several performance and cruiser platforms (e.g., many Harley‑Davidson big twins) use dry sump designs.
• Off-road and marine performance: Vehicles facing sustained angles or sloshing benefit from constant oil pickup.

While common in racing, the technology is increasingly integrated into premium performance road cars where track use is expected.

Design Variations

Dry sump systems are configurable to balance performance, cost, and packaging. The variations below are among the most common.

• Stages: From two-stage (one pressure, one scavenge) to five-plus scavenge stages for comprehensive crankcase evacuation.
• Tank architecture: Cylindrical, baffled, or labyrinth internal designs with built-in de‑aeration and heaters for cold climates.
• Integrated vs. external tanks: Some engines (e.g., certain 911s) integrate the reservoir into the crankcase casting.
• Pump drives: Belt-driven external pumps in race cars; gear-driven internal pumps in production applications.
• Semi–dry sump solutions: Hybrid systems using shallow pans, baffles, and limited scavenging for packaging and cost control.

These options let engineers tailor oil control to the engine’s architecture, intended use, and regulatory constraints.

Maintenance and Ownership Tips

Because a dry sump operates differently from a wet sump, proper checks and service are essential. The following points help ensure reliability.

• Oil level checks: Follow maker guidance—often at full operating temperature with the engine idling to get an accurate tank reading.
• Priming after service: After oil or filter changes, prime the system to prevent dry starts; some setups require cranking with ignition disabled.
• Inspect hoses and fittings: Look for chafing, heat damage, and seepage; replace aged lines proactively.
• Filter and screen service: Don’t overlook scavenge-side strainers; monitor for metal or debris as early warning signs.
• Watch temperatures and pressure: Fit quality gauges or loggers; anomalies often indicate aeration or flow restrictions.
• Mind fill volume: Overfilling increases aeration; underfilling risks starvation—use the manufacturer’s specified capacity.

Routine attention preserves the system’s advantages and prevents small issues from becoming expensive failures.

Common Myths

Despite their reputation, dry sump systems are sometimes misunderstood. These clarifications separate fact from fiction.

• “They’re only for race cars.” Many road cars and motorcycles use them for packaging and reliability benefits.
• “They always add lots of weight.” The tank and lines add mass, but a shallow pan and lower engine placement can offset overall impact.
• “Any dry sump prevents all starvation.” Poorly designed pickups, tank baffles, or plumbing can still cause issues; execution matters.
• “Maintenance is the same as wet sump.” Procedures differ, especially level checks, priming, and scavenge filter care.

Understanding these nuances helps owners and builders make informed choices about lubrication strategies.

Summary

A dry sump oil system stores oil in a separate tank and uses dedicated pressure and scavenge pumps to deliver steady lubrication and de-aerated oil under extreme conditions. The design enables lower engine placement, better oil control in high g maneuvers, reduced windage, and superior thermal management—at the cost of added complexity, packaging demands, and maintenance. It’s the go-to solution for motorsport, aviation, and increasingly, high-performance road cars where consistent, robust lubrication is non-negotiable.

What are the disadvantages of a dry sump system?

One notable drawback is their increased complexity. Dry sump systems require additional components, such as an external oil pump, oil lines, and a separate oil tank. This can make installation and maintenance more challenging, as well as increase the overall cost of the system.

What are the benefits of a dry sump oil system?

The benefits of a dry sump oil system, often seen in high-performance vehicles, include improved engine reliability, consistent oil pressure and lubrication under high G-forces, a lower center of gravity for better handling due to the shallow oil pan, increased engine power from improved crankcase vacuum and reduced oil drag, and better control over oil temperature. These advantages are achieved by storing most of the oil in an external tank and using external pumps to scavenge it from the engine’s crankcase, which keeps it from sloshing away from the pump pickup in a wet sump system.
 
Engine Performance and Reliability

• Consistent Oil Pressure: Opens in new tabExternal pumps continuously scavenge oil from the engine, preventing the oil pickup from losing suction and ensuring constant oil pressure and lubrication even during extreme cornering, braking, or acceleration. 
• Reduced Oil Starvation: Opens in new tabThe system eliminates oil starvation by continuously supplying the engine with oil, a critical benefit for high-performance applications and aerobatic aircraft. 
• Increased Horsepower: Opens in new tabBy creating a vacuum in the crankcase and reducing the drag from the crankshaft spinning through the oil, dry sumps improve ring seal and overall engine power. 

Handling and Weight Distribution 

• Lower Center of Gravity: Opens in new tabA shallower oil pan allows the engine to be mounted lower in the vehicle, resulting in a lower center of gravity and improved vehicle stability and handling.
• Flexible Oil Reservoir Placement: Opens in new tabThe external oil reservoir can be located in various positions, allowing for better weight distribution within the car, which is advantageous for overall handling.

Cooling and Oil Volume

• Improved Oil Cooling: Opens in new tabAn external oil reservoir can be designed for better cooling, allowing for more effective control of engine and oil temperatures, especially during heavy use like track driving. 
• Increased Oil Capacity: Opens in new tabDry sump systems allow for a larger total oil volume to be held in the external reservoir, which enhances engine cooling and longevity. 

Other Advantages 

• Degassing: Some systems include dual pumps to remove air and exhaust gases trapped in the oil, preventing froth that can reduce lubrication effectiveness.
• Turbo Lubrication: Dry sumps are beneficial for lubricating turbos, which operate at extremely high speeds and temperatures.

What is the difference between wet and dry sump oil system?

A wet sump system stores oil in the engine’s oil pan, offering simplicity and lower cost, but can experience oil starvation under stress. A dry sump system uses a separate external reservoir and two pumps to circulate oil, providing better lubrication and control under high G-forces, allowing for a lower engine placement and higher performance, though at the cost of increased complexity, expense, and maintenance. 
Wet Sump System

• Oil Storage: Oil is stored in a deep oil pan located directly under the engine. 
• Oil Pump: A single oil pump picks up oil from the pan and circulates it through the engine. 
• Advantages:
  • Simplicity & Affordability: Wet sump systems are less complex and generally more affordable to install and maintain. 
  • Compactness: They are more compact, making them suitable for everyday driving vehicles. 
• Disadvantages:
  • Oil Starvation: During high G-forces, such as rapid cornering or acceleration, the oil can slosh away from the pump’s pickup, leading to a temporary loss of lubrication and potential engine damage. 
  • Limited Oil Capacity: Wet sump systems typically have a limited oil capacity. 
  • Crankcase Oil Aeration: The crankshaft can “cut” through the oil in the pan, causing foaming and reducing lubrication efficiency. 

This video demonstrates the differences between wet and dry sump systems: 59sEngineering ExplainedYouTube · Jan 4, 2017
Dry Sump System

• Oil Storage: Oil is stored in a separate, external tank or reservoir, keeping the engine’s sump (pan) shallow and largely dry. 
• Oil Pumps: The system uses at least two pumps: a scavenge pump to remove oil from the engine’s sump and a pressure pump to send oil from the reservoir to the engine. 
• Advantages:
  • Superior Lubrication: The separate reservoir and multiple pumps ensure consistent oil supply, preventing oil starvation even under extreme G-forces. 
  • Improved Engine Performance: By reducing oil sloshing and crankcase windage (power lost to churning air), dry sumps can slightly improve horsepower. 
  • Better Packaging: The shallower oil pan allows the engine to be mounted lower in the chassis, improving the vehicle’s center of gravity and handling. 
• Disadvantages:
  • Complexity & Cost: The additional pumps, lines, reservoir, and fabrication make dry sump systems significantly more expensive and complex to install. 
  • Increased Maintenance: The added components require more maintenance. 
  • Potential for Leaks: The extra oil lines increase the number of potential leak points. 

Which System to Choose?

• Wet Sump: Opens in new tabIdeal for everyday vehicles, street cars, and lower-level racing where simplicity and cost are primary concerns. 
• Dry Sump: Opens in new tabEssential for high-performance racing, endurance, and applications with extreme G-forces (like Formula 1, aerobatic aircraft, or high-performance motorcycles) where maximum oil control and engine protection are critical. 

Is a dry sump system street legal?

In short, yes. Running a dry-sump system is a perfectly streetable solution, and frankly, a lot of manufacturers sell their high-performance and sports cars with dry sump systems straight from the factory.