Damn, now I have to do it. It will be a while, I'm super busy at work and even though I live in Georgia it's cold for a few more weeks. (Car fits in garage but no room around it)

 

I love catch can threads
Short answer: NO you do NOT want a catch can if you can avoid one

Usually if you find oil in the intake of a typical engine it means the PCV system is not properly routed or maintained. You may have installed a high flow air filter and removed the factory paper filter which provides the PCV suction at WOT you need to keep the oil out of the intake manifold. Or there is a leak between the OEM paper filter and the throttle body.
Or the PCV valve is incorrect or leaking, or the lines are shot

The engine has a baffle (oil air separator) in the valve cover which can prevent oil from seeping into the PCV lines that lead to the intake manifold....
However. This baffle is dependent on a crankcase pressure drop of 1 to 3" of Hg at ALL TIMES.

In other words, if you modify the engine to exceed OEM baffle design (very high rpm for example), or the factory air filter (typical), pcv system, or any of those parts goes bad, the engine may begin to aspirate oil. That doesn't mean it needs a catch can! It just means you need to service the pcv, and verify the crankcase pressure drop is 1 to 3" Hg at all times,
take corrective measures. Clean out the intake manifold (just wash it out with water and soap, remove from engine first ) And it will be fine as long as the RPM and oil flow hasn't been tampered with (9000rpm + high pressure oil pump might be too much for the baffle)

Let me share some examples
1. truck engines, specifically 4.8/5.3/6.0L have "typical oil in the intake" issues. LOTS of people encounter this issue right?
Well for every truck engine I've ever diagnosed, there has always been one of these as the culprit:
A. broken piston
B. bad PCV valve or cracked pcv hoses
C. wrong air filter / WOT pressure drop

I ALWAYS remove the catch can, clean the intake, new hoses/pcv valve, and replace the OEM air filter, and WHAM no more oil in the intake.

Next, forced induction variants: RB26DETT and 2jz-GTE are common turbocharged 500-800rwhp swaps I deal with regularly.
Same deal here, I remove the catch cans, clean up the hardware (soap and water), new pcv hoses, and deal with the air filter so that it can provide 1 to 3" Hg at WOT.

And WHAM no more oil spraying out of the engine.

The trick is the 1 to 3" of Hg inside the crankcase at all times. Cruise, idle, wot. That low pressure drop keeps the oil inside the engine. That is the main purpose (IMO) Of PCV. Rapid removal of combustion gas keeps oil out of engine seals. Pressure is vectorless, directionless; if there is 1psi of air pressure in the crankcase that 1psi will force air AND oil into every seal (front/rear main, valve cover gaskets, etc... start leaking) and also into the valve cover baffles where the oil will collect over time, gradually spilling over into the intake manifold.

 

That is a complete answer. Forgive my ignorance but what is WOT?

 

Wide open throttle

 

Some people like the look of catch cans. There is no issue to add one, as long as you verify the crankcase pressure drop is adequate.
Here is a conversion of inches mercury to inches of water




3" of Hg is around 40" of H2O So you can get a gauge that reads 0 to 55"~ of Water and that will be plenty of resolution to set the crankcase flow and pressure.

Alternatively, arduino are $20~ range and they can easily be used to detect 0-5v Sensors such as MAP SENSOR.
A 2-bar map sensor ($13~) is 0-5V Sensor that can be used to log the crankcase pressure (total cost < $50)
Logging is ideal because you can watch the road, make wot passes, or drive for a while, then go back and check the log.

Alternatively, HPtuners ECU uses a 0-5V EGR which can be used as WIDEBAND signal, OR, It can be used for 2-bar map sensor to log crankcase pressure.
This is effective, works for GM ecu HPtuners scanner config, avoids the arduino completely.