It’s safe to say that GM’s popular LS-series engines have supplanted the legendary small-block Chevrolet as the “go-to” powerplant for everything from street rods to off-road trophy trucks. Millions were produced in a decades-long run that started with the LS1 in 1997 and continued through the LS9. Though the LS was replaced by the LT platform in 2014 model GM production vehicles, it’s still available in crate motor form, in both wet- and dry-sump versions.
While the LS has many positive attributes, lubrication is not one of them. The OEM gerotor oil pump mounts to the front of the block and is crank-driven, meaning it spins at twice the speed of a standard small-block Chevy pump that lives in the pan and is driven off the camshaft. At higher RPM, the LS pumps can cavitate and cause problems with oil delivery. Additionally, the skirted block design of the LS limits the ability to reduce windage through traditional pan/windage tray options. For reasons like this, GM opted to employ dry-sump lubrication systems from the factory in the high-performance Z06 Corvettes starting in 2006. It’s also the reason Aviaid Oil Systems has taken such an interest in the platform.
Founded in 1961, Aviaid was the original supplier to Carroll Shelby for his Cobras and LeMans-winning GT40 and introduced dry-sump technology to motorsports via Bruce McLaren’s all-conquering Can-Am cars of the late 1960s. Current owner John Schwarz, who had an engine building and manufacturing background, took over the helm in the late 1990s and has maintained the company’s focus on technology.
Advantages of Being Dry
There are numerous advantages a dry-sump has over a traditional wet-sump setup. Of paramount importance is that the engine oil is evacuated from the pan and pumped to a remote tank — not left in the sump of the pan. Not only does this reservoir provide a fresh supply of oil to the externally mounted pump, but usable horsepower is increased through the elimination of “windage” that impedes the crankshaft and rotating assembly.
Simultaneously, the problem of oil starvation that comes during hard acceleration, braking, or cornering with a conventional wet-sump system is eliminated. Significant kinetic forces can cause oil to collect away from the reach of in-pan pickups and is something that oil pan manufacturers have been fighting since the dawn of time.
Other, ancillary benefits to a dry-sump oiling system include the use of a shallow oil pan, enabling the engine to be placed lower in the vehicle for a better center-of-gravity, or in some cases, allowing for hood clearance. Not to mention the constant availability of a larger quantity of fresh, cooler lubricant. Add to that the ability to control both the oil volume and pressure externally, and the ability to add extra sections to the pump to evacuate and pull vacuum from different locations on the engine, and it starts to become clear just how different a dry-sump is from a wet-sump system.
Drying the LS Out On The Street
Given all the different engine and chassis combinations the LS platform has found a home in — both OEM and not — and the wide variety of applications (drag racing, auto-cross, off-road, drifting, etc.), there’s certainly not a “one size fits all” solution. That’s why Aviaid Oil Systems had developed no less than seven kits for LS applications.
For street use and mild competition, Aviaid offers its “LS-A” package with a two-stage scavenge pump that’s mounted to the cylinder head on the right side of the engine and uses a Gilmer drive belt (think: cogged timing belt) to drive the external scavenge pump and utilizes the OEM gerotor pump for pressure. This setup relieves the factory pump of its scavenging duties and leaves it to simply pump oil from the tank to the engine.
The “LS-B” package also uses the OEM oil pump to supply the pressure, and is available with a two or three-stage scavenge pump, mounted to the factory A/C bracket bosses. The LS-B’s external pump is driven by a traditional six-rib serpentine belt. Removing the factory gerotor pump from the equation is the LS-C package. It uses a three-stage pump that mounts to the right side of the engine block and uses a dedicated HTD belt to drive it. Two pump sections are used for scavenging the pan and one stage is dedicated to feeding the engine.
Getting More Complex
Aimed more at competitive applications is the LS-D kit. It includes a four- or five-stage pump which mounts to the right side of the engine block and is driven by an HTD belt. This offers additional scavenging locations, which can also act as a source of crankcase vacuum.
Then, for installations that dictate the pump be mounted on the left side of the engine Aviaid offers the “LS-F” and “LS-G” combinations. They are both three-stage pump kits, for scavenging and pressure, and are driven by an HTD belt. The primary difference between the two left-mounted kits is that the “G” uses a drive pulley that’s mounted in front of the damper and allows the retention of factory air conditioning.
It should be noted that several options are available to customize the installation of any of the kits. In addition to the familiar Series 1 pump that is gear driven, a Series 2 pump that has rotors (Roots type) for increased scavenging efficiency better suits some applications. Likewise, there are options in the oil pan department that include fabricated steel and aluminum, cast aluminum, and billet aluminum options to suit your budget and application. Oil tank sizes and capacities are likewise variable.
Converting an LS engine doesn’t have to be a difficult undertaking, nor does it need to be a race-only operation, which is exactly Aviaid’s goal in creating all of the LS dry sump kit variants.
Ed. Note: This article was provided by the manufacturer, but contains sound technical information.