Many people have been asking why a catch can is needed, let me try to sum it up in the easiest way possible.
All cars, turbocharged or not suffer from something called blow-by. Blow-by is excess oil pressure that makes it through the factory PCV system and gets routed back into your intake where it can make its way onto your intake valves. Over time the valves become gunked up with oil and carbon deposits. With normal fuel injected motors this wasn't as big of a deal because the fuel injectors would spray the valves during combustion, hence cleaning them a little. However on modern cars like the Fiesta ST which are direct injected, the fuel is injected directly into the cylinder for a cleaner and more efficient burn. The problem with this is that the valves are no longer being cleaned by the spray from the injectors. So now excess oil vapor is being sucked back into your intake, your valves are getting coated, and your car is not running efficiently.
Here is where the catch can comes into play. By using a catch can that mounts in-line with the PCV system, it will trap that oil vapor that would have otherwise made it into your intake. Our catch can is going to be one of the largest on the market, so customers will not have to be bothered with emptying the car very often.