The Evo X has a traditional style of breather system, that being a pipe joining the airfilter to the rear of the cam cover and a pipe joining the cam cover to the inlet manifold via a PCV mounted in the cover itself.
At idle and cruise, the PCV opens and blow by gases are drawn from the cam cover and into the inlet manifold to be burnt in the normal combustion process. Unfortunately these blow-by gases are saturated with oil mist which effectively lowers the octane of the fuel, and over time coats the inside of the inlet manifold with oily sludge which further reduces performance. The Forge oil catch can system for the inlet manifold side of the engine uses baffles to catch the oil mist as it goes from the cam cover to the inlet manifold, and collects the residue in a catch tank mounted low down behind the bumper. Draining is made easy by a drain bolt that can be accessed just under the front of the car, and the inlet manifold draws in ‘clean’ air to burn.
Forge have also developed an additional catch tank system to combat the problem of oil in the turbo and inlet.