The 20-0378 Crankcase Catch Can Kit, Fiesta ST secures to the 2 ECU mounting studs in the back LH side of the engine bay and the entire kit fits under the OEM engine cover with no modifications required.
This catch can runs inline with the crankcase vent port. At low loads it experiences atmospheric pressure, but when the engine is at high load (WOT), this hose will experience high flow out of the crankcase. This would normally lead to oil and sludge accumulation in the air filter intake pipe. Oil accumulation will occur in the intercooler which lowers the thermal efficiency properties of the heat exchanger and leads to decreased performance.