Simply put, a sump is a pit that collects liquids. A more focused explanation would be, "the chamber in the bottom of any engine that collects lubricants for redistribution" as explained by Besel Motorsports. The terms wet and dry sump are most commonly associated with the oil circulating system of an engine, but can also be used in reference to plumbing systems.
A wet sump system for oil circulation in an engine is commonly found in passenger cars. In a wet sump system oil is stored in the oil pan, where it is recirculated directly back into the engine by the oil pump. The main benefit to a wet sump system is its easy modification for oil control and power since it is the original system included in a car's engine. The wet sump system is also low-cost, lightweight, simple and common, making it the logical choice for most passenger cars and light racing. However, for serious racers, there are distinct disadvantages to the wet sump system. It limits power, is slightly bulky and is inadequate to deal with the extreme shifts in motion.
A dry sump system is most commonly found in race cars for its additional power. A dry sump system pumps oil from the oil pump and filters it to an outside tank where it is then recirculated back into the engine. The main advantage to the dry sump system is increased power through reduced oil splash, or windage, and an improved ring seal between the oil pan and engine block. The dry sump system also allows for lower engine placement because of its shallower oil pan, increased oil capacity due to the external oil tank and continuous lubrication. The main disadvantages to the dry sump system are its complexity, high cost and its limited use as a mainstream oil circulating system.
Sump in Plumbing and Homes
The sump systems commonly referred to in plumbing or housing construction resemble a less complex version a dry sump system. A sump pump is commonly used for septic tank maintenance or to prevent basement flooding. The pump has four main components, a drainage pipe, discharge pipe, sump tank, sump pump and float. There are two main types of sump pumps used for septic tank and home use, a submersible pump or pedestal pump. The submersible pump goes directly into the sump tank and is completely concealed within the tank. The pedestal pump is also located within the sump tank but has a column jutting out from the tank.