Inside the crankcase pressure builds from the movement of the pistons and from blow by past the piston rings. Modern engines combat this through the PCV system. When X amount of pressure builds, the PCV valve is forced open and the noxious, oily mess from the crankcase is pushed into the upper intake manifold. This contaminates your air charge, heats it up, and takes up space with non-oxygen rich air.

Built primarily for drag race applications, crankcase evacuation systems are designed to reduce pressure build-up in the engine crank-case. The results are better piston ring seal, less intake charge contamination, and reduced oil leaks, while increasing engine performance.

I'm hoping to have gained around 5-8 hp from this system. I don't know how much of a benefit would be had in an engine that wasn't running under high compression.

Procedure

This is an easy mod. Here's what you do:
1. Disconnect the PCV hose.
2. Cap the PCV valve.
3. Attach a breather filter to a hose connected to the crankcase where the PCV hose was formerly connected.
4. Route the hose and filter away from the engine so that you can pull the coolest air possible.
5. Disconnect the hose from the crankcase to the air intake tube.
6. Cap or plug the air intake tube.
7. Run a new hose from the crankcase to a catch can or air/oil separator.
8. Run a hose from the catch can or separator to your vacuum pump.
9. Route a hose from your vacuum pump exhaust out of the engine compartment.
10. Run switched 12 power to the pump or hook up a switch inside the car via a relay for manual control.

Pictures


The black, bulbous device is the vacuum pump. The silver cylinder is the catch can. The hose goes from the crankcase to the catch can to the vacuum pump.

Cost

The vacuum pump was around $130. Beyond that, all you need is hose, hose clamps, small breather filter, relay, switch, and wire.