Crankcase Vacuum System

This reher morrison big block chevy illustrates the simplicity of an external vacuum pump system.

Crankcase vacuum system.

It s an engine performance trick practiced since the late 60s first with passive crankcase evacuation methods or so called pan evac systems. Moroso offers a lineup that includes both 3 and 4 vane vacuum. If you run a dry sump system with a three stage pump one pressure stage two scavenge stages in most cases you cannot achieve a sufficient level 8 hg of crankcase vacuum to achieve that power gain. To get the pressure even lower into a state of vacuum another option is to employ a vacuum pump on your engine.

The vacuum part of the pvc system provides the motive power for the flow of clean fresh air through the crankcase and into the inlet manifold via two routes taking with it the various crankcase emissions to be burned up during the combustion process. If you can achieve a crankcase vacuum level of at least 8 inches hg you will very likely realize an immediate power gain of at least 15 hp. Designed primarily for drag race applications this crankcase evacuation system is designed to reduce pressure build up in the engine crankcase. While the design is very complex the operation is very simple to explain.

Today manipulating the pan vacuum with a dedicated pump such as those offered by gz motorsports and moroso is more effective and gives the engine builder another tuning tool. The extreme solution to prevent all of this is to install a vacuum pump that continuously draws the pressure out of the crankcase. In an internal combustion engine a crankcase ventilation system removes unwanted gases from the crankcase the system usually consists of a tube a one way valve and a vacuum source such as the intake manifold. Our crankcase vacuum system is very complex in design and every hole groove passage and vent are critical to its successful operation.

For most modest horsepower street engines however a vacuum pump. This provides a better piston ring seal less intake charge contamination and reduces oil leaks caused by high crankcase pressures while increasing engine performance. A properly designed vacuum pump system can deliver like crankcase vacuum to a dry sump. Crankcase pressure is evacuated via the valve cover and pumped to an external tank which vents the pressure and retains excess oil for periodic draining.