Audible dot com is the leading provider of downloadable digital audio books and spoken word entertainment. Audible has over one hundred thousand titles to choose from to be downloaded to your iPod or MP three player. Go to audible podcast dot com slash brain stuff to get a free audio book download of your choice when you sign up today. Welcome to Brainstuff from hastaff works dot com where smart happens. Hi. I'm Marshall Brain with today's question. Why do some engines
use a dry sump oil system? Most production cars have a wet sump oil system. The oil that you put into the engine is stored beneath the crankshaft in the oil pan. This pan has to be large enough and deep enough to hold four to six quarts of oil. Think about two three liter bottles of soda and you can see that this storage area can be pretty big. A wet sump, the oil pump sucks oil from the bottom of the oil pan through a tube and then
pumps it to the rest of the engine. In a dry sump, extra oil is stored in a tank outside the engine rather than in the oil pan. There are at least two oil pumps in a dry sump system, one polls oil from the sump and sends it to the tank, and the other takes oil from the tank and sends it to lubricate the engine. The minimum amount of oil possible remains in the engine. Dry sump systems
have several important advantages over wet sums. First, because of dry sump doesn't need to have an oil pan big enough to hold the oil under the engine, the main mass of the engine can be placed lower in the vehicle. This helps lower the center of gravity of the engine and can also help aerodynamics by allowing a lower hoodline. The oil capacity of a dry sump system can be as big as you want. The tank holding the oil
can be placed anywhere on the vehicle. In a wet sud ump, turning, breaking and acceleration can cause the oil to pool on one side of the engine. This sloshing can dip the crank shaft into the oil as it turns, or it can uncover the pumps pick up to excess oil around the crank shaft in a wet sump can get on the shaft and cut horse power. Some people claim improvements of as much as fifteen horse power by
switching to a dry sump. The disadvantage of the dry sump system is the increased weight, complexity, and cost from that extra pump and the tank itself, but that's a small price to pay for such big benefits. Do you have any ideas or suggestions for this podcast? If so, please send me an email at podcast at how stuff works dot com. For more on this and thousands of other topics, go to how stuff works dot com and be sure to check out the brain stuff blood on
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