Radium Engineering’s Dual Catch Can Prevents Performance-Robbing Oil Buildup on the Subaru WRX

Photography: Mike Maravilla

  • Since 2010, Radium Engineering’s goal has been to design and produce high-quality aftermarket automotive performance products.
  • Radium Engineering specializes in motorsport-trusted fluid and fuel management tools to ensure your car performs at its very best.
  • Aside from its performance potential, the FA20F-powered Subaru WRX is known for its excessive blow-by in the turbo air inlet pipe thanks to its engine layout.
  • The Radium Engineering dual catch can kit intercepts the PCV gasses and traps the oil and other pollutants before they can make it back into the intake stream.

As the world continues to become increasingly turbocharged, there is one mod that has rocketed up the priority list: the oil catch can. As the name suggests, it gathers the engine’s polluted lifeblood into a cylindrical repository. In layman’s terms, this can serves as a jailhouse for contaminated oil and fuel so that it can’t wreak havoc on your engine’s intake manifold. One of the most notorious producers of this blow-by material is the FA20F-powered Subaru WRX. It should come as no surprise, then, that a catch can would be extremely beneficial to this platform.

I’ve found that amongst all of the manufacturers who have made these handy devices, Radium Engineering, ranks amongst the best. Since 2010, it has dedicated its entire operations to the ideation, testing, and production of fluid and fuel management components. Its success in this field has opened doors to new opportunities since, but these original tools continue to impressively evolve to meet the aftermarket’s growing needs. At present, Radium Engineering produces an impressive array of catch cans, including a dual-can version we’re going to install today.


While turbocharging has certainly become a more commonplace term to meet ever-tightening emissions standards, direct-injection internal combustion engines also play a large part in increasing the catch can’s popularity.

Despite being less efficient, port-injected engines were able to use the fuel being sprayed into the intake as a cleaning agent, helping wash away any oil buildup that might occur. By contrast, direct injection engines shoot fuel directly into the cylinder. This process makes for a cleaner ignition, but it literally has no ability to tidy up after itself. Over time, this lack of housekeeping can lead to poor fuel economy, misfires, or an overall reduction in power.


Without going into the inner workings of an internal combustion engine, the build-up that you see on your intake valves is a mixture of untidied oil, fuel, and other contaminants from your engine’s crankcase. This sounds like a long way to go — and it is — but all of that muck is able to travel from your engine’s bottom end because of the Positive Crankcase Ventilation (PCV) system.

While this PCV system has benevolent intentions to alleviate crankcase pressure, the blow-by material that we mentioned earlier can also take this route. There, oil and contaminants accumulate onto your intake valves as carbon deposits.

Radium Engineering’s oil catch can acts as a mediator between the PCV system and the intake manifold. By routing the pressure (and the blow-by) into its chamber, the catch can is able to filter the muck from the air. The blow-by stays in the can and the air gets recirculated or vented to the atmosphere.


As I alluded to earlier, not every direct-injection motor produces the same amount of blow-by, but thanks to the FA20F’s inherent layout, the 2015-2021 Subaru WRX is one of the worst offenders. Radium Engineering’s Dual Catch Can Kit (20-0256-FL) helps manage the WRX’s carbon build-up in two ways: the forward catch can intercepts the Closed Crankcase Ventilation (CCV) line and the rear catch can intercepts the Positive Crankcase Ventilation (PCV) system we mentioned earlier. In this case, vacuum is created in two separate instances — on throttle and off respectively — which allows the Radium Engineering catch cans to work in tandem to filter blow-by.

Radium Engineering catch cans feature large 10AN ORB ports, a 4AN ORB drain port, and two-step oil separation baffling. Each catch can holds seven fluid ounces and has its own o-ring sealed dipstick so you can keep track of whether they need to be purged.

“The direct-injected Subaru FA20F engine in particular has an inherent problem since there are no port injectors to clean the backside of the intake valves,” confesses Aaron Suchy, co-founder of Radium Engineering. “This (dual catch can) kit is perfect for stock or modified street cars as a preventative measure to keep oil and sludge out of the intake tract, intercooler, and intake manifold.”


As always, we called upon the services of R/T Tuning in Montgomeryville, PA to help us fit the Radium Engineering Dual Catch Can Kit to a local WRX. Don’t let the 38-step PDF instruction guide scare you — the installation is incredibly straightforward and the kit actually attaches to the WRX’s factory mounting points. As Radium Engineering suggests, we removed the passenger-side radiator fan to gain better access to the crankcase vent hose.

Radium Engineering includes ample hose length for both the PCV and CCV side so you can get a bit more creative with the routing, should you need it.


Servicing the catch can couldn’t be easier. For stock or lightly modified examples, Radium Engineering recommends checking the catch can fluid level every 5,000 miles. In more extreme cases (dedicated track or highly modified cars), the dipstick should be checked much more frequently.

Using the Radium Engineering Dual Catch Can Kit properly will pay dividends to your engine’s overall health, too. The kit effectively raises the fuel octane, increases engine performance (from cleaner inlet air), and lowers hydrocarbon emissions. As a result of all of this, the Radium Engineering Dual Catch Can Kit is 49-state legal.

Given all the benefits, the Radium Engineering catch can offerings should be considered mandatory for Subaru WRX owners. For the majority of street or hybrid street/track cases, the Dual Catch Can Kit is the one we’d choose. But given Radium Engineering’s glowing, motorsport-trusted reputation, you can’t go wrong with any of them.


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