Catch Can Insight
 

I had a catch can installed recently (when my car ran) and when it was first it was setup like the first picture. In the first setup it burned all my oil out of the exhaust and blew the oil out of the reservoir. I would like to know why and what’s wrong with that setup

For the second setup i cut the second hose connected on the intake side and plugged the hose into the intake manifold and the valve cover as you can see, then the hose that was there connected to the catch can is just left open and not being used at all anymore.
I haven’t seen this setup on the sticky forum, so want to know what’s happening here and why it works
Any help appreciated





https://cimg0.ibsrv.net/gimg/www.mia...e01ede4bc.jpeg
First broken setup
https://cimg1.ibsrv.net/gimg/www.mia...f50b0371c.jpeg
Second working setup

You need to vent your crankcase. Crankcase is the air in your oil pan, block drains, and valve cover. Small gaps between the tips of the piston rings allow cylinder pressure into the crank case, and this needs to be evacuated.

The factory setup is ideal for most setups, however the air in the lines often contains vapors of oil, which you're trying to catch with the catch can. So air is out, oil is in catch can.

What you did in your first setup is a sealed system, no air is allowed out. You'll push oil seals (front main, rear main, cam) out of their seat, among many other issues.

What you've done in your 2nd photo is decent, however you engine is still ingesting the oily vapor that's going from the PCV to the intake manifold. Ideally you have 2 catch cans, one between the exhaust side of the valve cover and the silicone elbow your air filter is attached to, and another between the intake side of the valve cover and the intake manifold. The PCV needs to remain to act as a check valve, so when your intake manifold is pressurized, it doesn't also pressurize the crankcase.

There are many connotations to breather setups.

The second setup - the open hose is now a vent - its also a potential air inlet to the crankcase when the inlet manifold is drawing vacuum. At minimum I'd put an air filter on it to avoid sucking anything in through the open hose end.

You're relying on the exhaust side vent to release crankcase pressure on boost when the PCV is closed. You may find this outlet is a little small depending on how much your engine breathes.

If you want to retain the single catch can setup reroute the intake port on your valve cover (right side) to the intake silicon elbow.
Run left side pcv valve output into the catch can, catch can back into intake manifold.

If you have excessive crank case pressure overpowering the pcv valve, remove pcv valve, plug up intake manifold and run the port on the left side into your catch can. Output catch can to atmosphere. The charcoal canister outlet port on the chassis frame bottom engine bay is good choice. ;)

Will this not mean that the breather pipe from intake manifold, the catch can itself, and the pipe from catch can up to the PCV valve are all under full intake boost and vacuum. Always sits odd with me. The catch can is only operating under idle and cruise in this config. If you're chucking oil out on boost then its going through the inlet, compressor, intercooler, intake, burning in combustion.

Yeah if he has worn rings and excessive crank case pressure and it's puking oil out of his the breather inlet port on the right, then no. This isn't a good idea.

Usually you'd get two catch cans or one with 3 ports and route both sides into the can, vent to frame / atmosphere.