Dry Sump Systems
10-09-2004, 09:26 PM
#11
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Re: Dry Sump Systems
A dry-sump oil system can also use a much larger volume of oil than a wet-sump. Adding a couple of quarts of oil to a wet-sump system can actually create more problems by increasing aeration and windage. With a dry-sump system, increasing oil capacity with a large external reservoir tank simply improves the overall effectiveness of the lubrication system.
An external oil tank also protects the engine against fluctuations in oil pressure. Keeping the oil pump pickup in a wet-sump system constantly submerged is extremely difficult, even with trap doors and baffles. With an external dry-sump reservoir, you won't see the oil pressure gauge hit zero after a burnout or when the parachute opens.
Removing the oil from the pan also reduces the demands on the piston rings to control the oil on the cylinder walls. Dry-sump engines can use oil rings with less tension than wet-sump motors. These low-tension oil rings cut friction and parasitic losses, leaving more power to accelerate.
A dry-sump system also allows you to optimize the oil pan design for maximum power. A wet-sump pan must be designed to collect the oil in a confined space; consequently it cannot have a large interior volume since this would dissipate the oil over a wide area. A dry-sump pan, in contrast, can be as big and wide as the chassis allows, with kick-outs and other windage-reducing features that improve engine output. Simply switching from a restrictive wet-sump system to a dry-sump lubrication system typically produces a 20 to 25 horsepower improvement in a large displacement engine, even without optimizing the piston package with low-tension rings. A dry-sump pan can also be shallower than a wet-sump pan to allow the engine to be mounted lower in the chassis.
An external belt-driven dry-sump oil pump eliminates the load and wear on the distributor gears in engines such as the big-block Chevrolet V8. Turning a high-volume internal oil pump requires considerable torque; this torque must be transmitted through the camshaft and distributor shaft. When we overhaul a wet-sump racing engine, the distributor gear almost always shows high wear. With a dry sump, the distributor gear only turns a plastic rotor, so wear is negligible.
My advice to racers who are considering a dry-sump system is to use a five-stage pump. I recommend three scavenge stages for the oil pan, one for the lifter valley, and a single pressure stage. The difference in cost between a three-stage and a five-stage oil pump is insignificant compared to the total cost of the pump drive, brackets, oil tank, oil pan, and lines - components that are required for any dry-sump system regardless of the number of stages.
Dry-sump lubrication also dramatically improves engine cooling, which is especially important for sportsman racers who have little time between rounds. In an air-cooled motorcycle engine, for example, it is really the oil that does most of the cooling by transferring heat away from the pistons and valves. The same effect takes place in a water-cooled engine - it is primarily the oil that pulls heat out of the piston tops and friction points such as bearings, lifters, pushrods, rocker arms, and valve springs. An aluminum dry-sump oil pan, aluminum oil tank, and the associated lines make a very efficient radiator to cool the oil. Maintaining a near-constant oil temperature can also improve consistency, which wins races in the brackets and heads-up sportsman eliminators. Finally, a dry-sump system oil system provides an extra margin of safety. Most oval-track classes require dry sumps because they reduce the danger of oil getting on the track after an engine failure or accident. I wouldn't race a fast drag car without a dry sump for the same reason. I have seen engines with dry-sump pans break connecting rods without putting an appreciable amount of oil on the track. There is a relatively small volume of oil inside a dry-sump engine, and it is widely spread out, so even a catastrophic engine failure seldom presents a hazard to the driver.
Certainly not every racer needs a dry-sump oil system. A dry-sump system is more expensive, more complex, and heavier than a wet-sump. A well-designed wet-sump system can provide troublefree service for the vast majority of engines. But with the growing popularity of big-inch motors that are capable of producing Pro Stock power levels, a dry-sump lubrication system becomes an excellent investment.
Its all about the money. Dry sumped is a superior oil system.
Just my 02
Hope this helps.
Gerry
An external oil tank also protects the engine against fluctuations in oil pressure. Keeping the oil pump pickup in a wet-sump system constantly submerged is extremely difficult, even with trap doors and baffles. With an external dry-sump reservoir, you won't see the oil pressure gauge hit zero after a burnout or when the parachute opens.
Removing the oil from the pan also reduces the demands on the piston rings to control the oil on the cylinder walls. Dry-sump engines can use oil rings with less tension than wet-sump motors. These low-tension oil rings cut friction and parasitic losses, leaving more power to accelerate.
A dry-sump system also allows you to optimize the oil pan design for maximum power. A wet-sump pan must be designed to collect the oil in a confined space; consequently it cannot have a large interior volume since this would dissipate the oil over a wide area. A dry-sump pan, in contrast, can be as big and wide as the chassis allows, with kick-outs and other windage-reducing features that improve engine output. Simply switching from a restrictive wet-sump system to a dry-sump lubrication system typically produces a 20 to 25 horsepower improvement in a large displacement engine, even without optimizing the piston package with low-tension rings. A dry-sump pan can also be shallower than a wet-sump pan to allow the engine to be mounted lower in the chassis.
An external belt-driven dry-sump oil pump eliminates the load and wear on the distributor gears in engines such as the big-block Chevrolet V8. Turning a high-volume internal oil pump requires considerable torque; this torque must be transmitted through the camshaft and distributor shaft. When we overhaul a wet-sump racing engine, the distributor gear almost always shows high wear. With a dry sump, the distributor gear only turns a plastic rotor, so wear is negligible.
My advice to racers who are considering a dry-sump system is to use a five-stage pump. I recommend three scavenge stages for the oil pan, one for the lifter valley, and a single pressure stage. The difference in cost between a three-stage and a five-stage oil pump is insignificant compared to the total cost of the pump drive, brackets, oil tank, oil pan, and lines - components that are required for any dry-sump system regardless of the number of stages.
Dry-sump lubrication also dramatically improves engine cooling, which is especially important for sportsman racers who have little time between rounds. In an air-cooled motorcycle engine, for example, it is really the oil that does most of the cooling by transferring heat away from the pistons and valves. The same effect takes place in a water-cooled engine - it is primarily the oil that pulls heat out of the piston tops and friction points such as bearings, lifters, pushrods, rocker arms, and valve springs. An aluminum dry-sump oil pan, aluminum oil tank, and the associated lines make a very efficient radiator to cool the oil. Maintaining a near-constant oil temperature can also improve consistency, which wins races in the brackets and heads-up sportsman eliminators. Finally, a dry-sump system oil system provides an extra margin of safety. Most oval-track classes require dry sumps because they reduce the danger of oil getting on the track after an engine failure or accident. I wouldn't race a fast drag car without a dry sump for the same reason. I have seen engines with dry-sump pans break connecting rods without putting an appreciable amount of oil on the track. There is a relatively small volume of oil inside a dry-sump engine, and it is widely spread out, so even a catastrophic engine failure seldom presents a hazard to the driver.
Certainly not every racer needs a dry-sump oil system. A dry-sump system is more expensive, more complex, and heavier than a wet-sump. A well-designed wet-sump system can provide troublefree service for the vast majority of engines. But with the growing popularity of big-inch motors that are capable of producing Pro Stock power levels, a dry-sump lubrication system becomes an excellent investment.
Its all about the money. Dry sumped is a superior oil system.
Just my 02
Hope this helps.
Gerry
10-11-2004, 10:44 AM
#12
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Join Date: Jul 2004
Location: Brew City
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Re: Dry Sump Systems
Thanks For The Replies, When I Pull My Motors To Upgrade Them I Will Be Installing Dry Sump Systems On Them.
$$$$ Can't Take It With You !!!!!!!!
$$$$ Can't Take It With You !!!!!!!!
