The Steeda
Focus ST Oil Separator for 2015, 16, and 17 Focus ST models reduces detonation, oil burning and
deposits on the valves by removing oil drawn through the PCV system before it can contaminate the intake charge.
This is
also very helpful with these turbo applications, where it is essential to keep oil from entering the turbo.
Excess crankcase pressure (sometimes known as "blow-by") is vented from the crankcase through the PCV system, where it is drawn into the intake manifold and returned by the engine. This re-circulated air contains aerated oil from the crankcase which is burned by the engine. Supercharged, nitrous boosted and high mileage engines often draw excessive amounts of oil into the engine through the PCV system.
The Steeda Focus ST Oil Separator for 2015-2017 Focus ST plugs into the PCV hose between the PCV valve and the intake manifold and removes aerated oil from the re-circulated air and collects it in a tube that can be drained and recycled. It's designed to maintain the factory sensor too in the PCV system.