OTC Ford Focus ST250 Oil Catch Can
"For a boosted setup with turbo or supercharger, the Breather line will recirculate some of these oils into the intake which could go into the intercooler and will also gunk up the intake manifold and intake valves"
An Oil Catch Can Tank is a simple device that benefits countless types of vehicles whether they are boosted with turbo or supercharger and normally aspirated vehicles can benefit as well.
To explain it simply, an oil catch can tank is a reservoir, or filter for a PCV line coming from the valve covers. There is also a Breather line associated with the PCV line. Both lines function together for the PCV emission system to work. When one side is positive pressure, the other side is negative pressure.
So why does somebody need an Oil Catch Can Tank ?
The reason is, that the valve rings do not create a perfect seal. If they did the pistons would not be able to move up and down. Because there is a tiny gap between the cylinders and the pistons, a little bit of pressure is able to escape into the valve cover area. At the same time burnt oils are also escaping into the valve cover area. This is called "blow by". This stuff is nasty and does enter the valve cover area and will escape into the PCV line and Breather. The PCV line will recycle these burnt solids back into your manifold which will increase the level of carbon solids, and reduce your octane levels. For a boosted setup with turbo or supercharger, the Breather line will recirculate some of these oils into the intake which could go into the intercooler and will also gunk up the intake manifold and intake valves. Of course, the intercooler works best when the interior surfaces are nice and clean. When the breather line returns any fumes with oils into the intake, this will start to coat the inside of the intercooler with oil, and reduce the heat exchange efficiencies.So, the simplest solution is to insert an oil catch tank can into each line, this gives these heavy oil solids a place to enter and pool. There are many shapes and sizes, and even different configurations which are closed-loop, and open loop.