RB20 RB25 Catch Can PCV Breather Guide

Title: Technical Articles: RB Catch Can/PCV Breather Guide

The info needed is not limited to what is found solely in the RB section in which this thread links to previous threads, but the same principles follow much of all other motors.

Previous threads which contain dialog of RB owners configuring their PCV and catch can setups (the good, the bad, and the ugly)…

For emissions related:
http://forums.nicoclub.com/zerothread?id=396474

For pictures of factory, modified, and custom setups:
http://forums.nicoclub.com/zerothread?id=127233
http://forums.nicoclub.com/zerothread?id=377141

Ok now that you have researched and read through those threads…

Here are some examples of how you may setup your PCV, Catch Can, Breather Can, Vacuum, etc system:

Cliff Notes:
* Crank case must vent pressure that accumulates in the engine.

* Either venting through a breather filter, catch can with breather filter, intake manifold, intake pipe, or exhaust.

* Best results are found when the crank case is experiencing vacuum.

* Vacuum sources generally used are intake manifold and intake leading into the turbo.

* If using the intake manifold as a vacuum source one must use a 1 way check valve to prevent the crank case from being pressurized when under boost. (read: pcv)

* If using the intake pipe leading into the turbo for vacuum, source must be after the MAF (if equipped).

* If using the exhaust pipe exiting the turbo for vacuum, 1 way check valves must be used to prevent exhaust gas circulating back into the crank case.

* If venting the valve cover either through a breather filter or catch can with breather filter(s), the factory PCV valve and intake port must be blocked off preventing those sources from sucking in unmetered air. (read: vacuum leak)

* Plumbing can be made of various materials. If near high levels of heat, use protective/heat reflective material or hoses that can sustain heat. (read: do not have the plastic PVC hose near exhaust)

*Catch cans can be made out of various materials or completed units purchased from various manufacturers.

* Catch cans with internal baffling, steel wool, etc. have found beneficial in removing oil from vented vapor.

* Baffles can also be adapted inside the valve covers of the RB25 and upgraded on the RB26.

This system is as important as anything else to provide optimal performance and reliability. Providing a proper ring and valve seal. This system mentioned above is primarily focused on wet sump oil system RB’s which differs when dealing with dry sump’d RB motors