PRI 2025: Inside Moroso’s New LS Tri-Lobe Dry Sump Oil Pump

Maintaining stable oil pressure and effective scavenging becomes critical as LS engines are pushed into higher RPM ranges and exposed to sustained acceleration forces. A properly designed LS dry sump pump removes the limitations of traditional wet sump systems by separating oil storage from the crankcase and ensuring a constant supply under all conditions. The tri-lobe right-side LS dry sump pump from Moroso is engineered specifically for competitive GM LS applications where reliability and efficiency matter just as much as horsepower.

This pump is designed to bolt directly to GM LS engine blocks using the factory A/C bracket mounting holes on the right side, combined with a front motor plate. This mounting strategy keeps the pump secure and compact while improving chassis and accessory clearance, which is especially valuable in race cars with tight packaging constraints.

Tri-Lobe Scavenge Design And Pressure Control

At the core of this LS dry sump pump are tri-lobe aluminum scavenge sections that use individual timing gears. This layout ensures precise internal clearances even at extreme engine speeds, reducing the risk of gear interference or efficiency loss. Effective scavenging pulls oil away from the rotating assembly quickly, reducing windage and preventing oil from entering the crankcase where it does not belong.

Oil pressure is handled by a 1.200-inch spur gear pressure section derived from Moroso’s billet wet sump pump design. Spur gears provide predictable pressure characteristics and excellent durability in high-load environments. Variable spring rates within the pressure section allow oil pressure to remain smooth and consistent, preventing erratic fluctuations during rapid acceleration, braking, or high-speed cornering.

Reduced Weight, Lower Power Consumption

One of the standout advantages of this LS dry sump pump is its efficiency. Compared to traditional gerotor-style pumps, it weighs nearly half as much and requires up to 40 percent less power to drive. Lower parasitic loss helps free up usable horsepower while still generating significant crankcase vacuum. Increased vacuum supports a better ring seal, reduces oil aeration, and provides more consistent power output throughout a run.

Plumbing Flexibility And Race-Ready Details

The pump includes replaceable fittings to simplify system integration. The pressure section features -12AN inlet and outlet ports, the scavenge inlets are -12AN, and the return uses a -16AN fitting. This configuration allows flexibility when pairing the pump with different dry sump tanks, hose routing layouts, and chassis designs.

For builders pushing LS engines beyond conventional limits, a properly designed LS dry sump pump is an essential foundation. Moroso’s tri-lobe system delivers proven oil control, reduced power loss, and race-focused engineering suited for drag racing, road racing, and endurance applications alike.