Radium Engineering Catch Can System for 2013+ Ford Focus ST/RS
Though both cans are recommended, the PCV system is more important than the Crankcase side. The crankcase side can be added later, but you can do a test to see how much oil you are getting in your stock intake inlet tube. Pull the hose off the back of the intake and stick your finger inside to see how much oil is in the tube. If you get a drop on your finger it is recommended to add the Crankcase system as well. If you get just a small amount/residue/smudge on your finger you are good.
Click Here to download installation instructions.
An oil catch can is essential on a performance vehicle to protect the engine from elevated levels of crankcase blow-by accumulated from high performance driving. Excess oil saturated air circulating back into the air intake stream can lead to degraded performance. Read about all the benefits and functionality of the Radium Engineering's popular catch cans here:
All Radium catch cans provide the following benefits:
-Effectively raises the octane and increased engine performance from cleaner inlet air
-Prevents oil buildup in the intake and intercooler system walls, throttle body, intake manifold, etc.
-Excessive oil collection can be an indicator of a damaged engine.
-Lowers hydrocarbon emissions
-Capacity: 6 fluid ounces each
2013+ Focus EcoBoost Catch Can Kit Details:
The Radium Engineering catch can kits are the most functional and integrated kits on the market. The catch cans mount using factory holes and integrate perfectly with the surrounding components. These two oil catch cans (PCV side and Crankcase side) function completely independent of each other and are sold individually or together. They do NOT vent to atmosphere (VTA), thus are emissions and track legal. Closed loop systems remove the oil and sludge from the PCV gasses before it is routed to the engine to be burned. A closed loop system also promotes negative crankcase pressure for optimal performance. Furthermore, closed systems prevent unwanted oil vapors from entering the cabin. The dipsticks built into the catch cans allow easy inspection of accumulated fluid. No cutting, drilling or permanent modification to the vehicle is required.
The 20-0315 PCV Catch Can Kit, Ford Focus is used in both the ST and RS models with the EcoBoost engine. It mounts on the front left bulkhead, as shown below.
This catch can runs inline with the PCV (positive crankcase ventilation) valve and retains it's factory function. When the intake manifold pressure is close to or greater than atmospheric pressure, the PCV "check" valve closes and, thus, this hose experiences no flow. Conversely, the PCV hose will experience "metered" vacuum when the engine is idling, steady state cruising, and decelerating. This would normally draw unwanted crankcase vapor, unspent fuel, and oil sludge into the intake manifold immediately after a high load run. Note: Because the Radium catch cans are pressure sealed, they are great for this boosted application so intake manifold connection is permitted.
The 20-0316 Crankcase Catch Can Kit, Ford Focus mounts on the high pressure fuel pump (HPFP) in the back left of the engine bay, as shown below. Because the ST uses a different HPFP than the RS, this kit is only compatible with the RS model. 
This catch can runs inline with the crankcase breather 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.
Each kit includes the following:
-Anodized oil catch can with integrated condenser and dipstick
-Anodized laser cut Focus specific mounting bracket
-Anodized aluminum -AN adapter fittings and hose ends
-Enough PCV hose for custom applications
-Stainless steel mounting hardware
For the ultimate in engine protection, Radium recommends the 20-0328 Dual Catch Can Kit, Ford Focus 
This kit utilizes both the "Crankcase" and "PCV" catch can kits, as shown below.
