TECH BONUS - Dry Sump vs Wet Sump

DrySumpvs. WetSump

LubricationSystems

by Bill Holland

The majority of vehicles manufactured around the world come with wet sump lubrication systems where the oil is contained in the pan and is circulated by an internal pump —generally driven off the camshaft. Some engines, like the Chevrolet LS, feature a crank-driven oil pump.

A large number of race cars and high performance street machines feature dry sump lubrication systems where the oil is contained in a remote sump tank and circulated with an externally-mounted pump that’s belt-driven.

And then there’s a “hybrid” setup that uses a remote oil sump tank, an externally mounted pump to evacuate the lubricant from the pan, and the OEM oil pump to supply the pressure. This is a popular way to overcome the shortcomings of the factory LS lubrication system.

For input on this critical “life blood” of an engine we turned to John Schwarz of Aviaid Oil Systems in Chatsworth, California.

Aviaid was founded in 1961 and the supplier to Carroll Shelby for the lubrication systems on his Cobras and LeMans-winning Ford GT40.

For some applications you can choose between Aviaid’s CNC-machined billet aluminum, cast aluminum and fabricated aluminum pans, as well as fabricated steel. Their low profile design facilitates lower engine placement.

Later, the company collaborated with Bruce McLaren to introduce dry sump technology into motorsports with his all-conquering CanAm cars of the late ‘60s.

According to John, “There are a number of key advantages to a dry sump system. They include increasing power through elimination of windage in the pan, assuring an ample supply of lubricant under hard acceleration, cornering or braking, and having cooler, cleaner oil.” He added, “Other advantages of the dry sump are that the pan profile is very low, which allows placement of the engine lower in the chassis, and external pressure regulators can be adjusted to your needs.”

You will note that dry sump pumps come with a variety of sections, ranging from a dual-section pump with one devoted to evacuating the pan and the other to supply pressure all the way to six and seven-section pumps. In some applications additional sections are employed for providing circulation of power steering, fuel and other liquids —as well as evacuating oil from valve cover areas, etc.

Extra sections can be added to dry sump pumps to provide increased system capacity. They also can be employed to provide fuel and power steering pressure.

Aviaid take it a step farther by offering two styles of pumps; its original Series 1 pump that features positive displacement gears in all sections and the Series 2 pumps with Roots-type rotors in all the scavenge sections. Rotors are more efficient, which translates into being able to use a shorter pump if space considerations are an issue. By way of example, Aviaid’s Series 2 pumps have been employed in George Poteet’s record-setting 400+ MPH “Speed Demon” Bonneville streamliner, which has serious space considerations.

For sure, a large number of Avi aid’s lubrication systems go into Pro Street, Pro Touring, Track Attack and Drifting applications. And the company has put together packages that contain all the required compo nents —except the “plumbing,” giv en the variations in where to mount the sump tank. Engines included are small and big block Chevy and Fords, LS, Ford Modular and Coy ote, Chrysler wedge and 426 Hemi, plus Gen III Hemi and several pop ular Sport Compact applications. Additionally, Aviaid has dozens of different mounting brackets (includ ing “universal” types) that facilitate equipping virtually any 4-6-8-10 or 12-cylinder engine with a dry sump system.

Highly efficient dry sump oil systems are available for “legacy” engines, such as the FE Ford.

External wet sump oil pumps can be employed, as shown this 426 Hemi. Dry sump systems are also available.

One of Aviaid’s more popular setups for LS engines combines an external scavenge pump and the OEM unit for pressure. It mounts to the cylinder head.

The Aviaid “LS-C” package features a 3-section pump (two scavenge, one pressure) which mounts to the block and employs a special ATI Super Damper with an HTD drive hub.

Aviaid’s

The newer for added

A typical dry sump system is comprised of a special oil pan, pump, sump tank, pressure regulator, oil filter, cooler and block adapter.

Configuring A Dry Sump System

The aerated oil is pumped into the top of the tank, where it passes downward through baffles to remove the air “bubbles.” Tanks are available in a variety of widths and heights.

Most systems include a 3-stage pump, mounting bracket, drive pulleys, belt, special oil pan and the sump tank. Variables include the pan (for some applications Aviaid offers fabricated steel and aluminum pans, plus cast and billet aluminum) and the sump tank, which come in 6”, 7.5” and 9” wide cylinders of varying heights to accommodate up to 5 gallons of oil. The tanks are baffled, which assures there is always oil to feed the engine, regardless of kinetic forces.

Installing a system on a late model Mustang, for example, involves attaching an adapter to the OEM Coyote filter mount, installing a remote filter mounting bracket, affixing the pump to the engine, adding a pulley to the front of the balancer (Aviaid has kits that include an ATI Super Damper), installing the dry sump tank, and running braided stainless steel lines as required (AN-12).

Additional information can be obtained by visiting the company’s website at www.Aviaid.com, sending an e-mail to aviaidHP@Gmail.com or calling 1-818-998-8991.

Aviaid’s Series 1 pumps feature gears in all sections, and a proven “workhorse” for some 50-plus years.

newer Aviaid Series 2 pumps feature rotors in the scavenge sections added efficiency. Accordingly, they can be smaller in length.