I am lead to believe this is common across all ecoboost platforms which are just revisions of the mazdaspeed motors. PCV system is weak and oil doesn't drain from the turbo well but when you have a cat in place there is exhaust back pressure that keeps the oil in the turbo to drain properly. With no cat and a free flowing exhaust there is less pressure so when oil builds up in the turbo the easiest way out is through the oil seal into the exhaust causing a bluish smoke. OCC will help but problem remains that when in boost the PCV closes and the only place for crank case pressure to vent is to work all the way up to the valve cover and then back into the intake. Fixes that have helped mustangs and mazdaspeeds where remove PCV and add better check valve, add an oil restricter bolt to the oil supply for the turbo, best solution was to use a new PCV plate with 2 outlets and run 2 better check valve with 2 OCC, one in VTA mode and one in closed. This has been heavily documented for both ecostang and mazdaspeeds and I hoped the FIST would not have the same issues. I came from the mazdaspeed platform to the FIST and I have done enough research on that and scostangs to make your head spin.
