This might be a stupid question, but is a recirculating catch can useful? I know in piston engines they are popular because they prevent pressure building up behind the pistons. But would that be beneficial to the rotary or is it best to just vent to atmosphere?

lol that design would work for sure but i love the note that says the line to be lower than the oil level so it does not blow up from crank case pressure lol!!!! its going to have pressure at every point of the crank case

any updates for those using stock twins?

My catch can setup drains back into the oil pan. I never have to empty it.

thewird

I meant recirculating the air not the oil.

That's how the stock setup does it. It vents everything back into the engine. Don't think theres anything wrong with that except it leaves oil in your IC & piping.

thewird

quick update to my thread based on question someone asked on the level viewer thing I added to my catch can. I took that off the previous can i had, but here is where you can get the parts to make/add one:


Check this mcmaster page:
http://www.mcmaster.com/#catalog/117/172

Maybe somthing like product#51055K48 for the elbow fittings, then just some clear plastic 1/4 inch tube to connect them (plastic that can handle oil) like mcmaster part #53945K111

As always, super helpful information! I tried looking through the McMaster website before but wasn't sure which part would work. Luckily, you just spelled it out for me! Now I have everything (minus the bracket to mount the can itself) and can finally put this thing together. I'll post up my own results when I'm done.

Thanks again Damian!

Up from the dead. How is this setup still holding up?

It always worked well however I sold the entire setup a while back as my current setup will be dry sump so my old setup no longer applied :-)

Oh you fancy, huh ;)

I'm about to purchase all the parts for this modification, the only issue is where can I get the RE Filler neck these days??

IRP makes one now

legend cheers

IRP is out of stock, is there any where else?

I thought IRP still had some dual -6 units in stock? This is what I am running. One port to the rear oil drain port and the other to a vented catch can for any crazy overflow (highly unlikely given the baffle design and dual side venting.

So the oil can transfer between the rear turbo drain and the filler neck? Hadn't thought of trying that.

Anyone tried this catch can? Universal Dual Catch Can Then I could see how much comes from the rear and how much from the filler. Also I like the media in there that allows the fuel to evaporate.

Blow by has been a big problem that I'm trying to solve. Apparently a lot of it is because the Pineapple oil pan has bad baffling (even with my trap doors around the pickup).

By venting from both sides, air will take the path of least resistance. The baffle in the filler neck will help as well. The catch can is mainly to catch the suspended residuals or in the event of one side getting clogged and oil exiting either side.

Here is the catch setup I just made,
Its using the stock pcv points and valve, mainly for simplicity I have a spare 9mm vacuum only port on my turbo inlet to swap to if I decide to later.


I purchased a cheap square ebay catch can and some fuel safe foam for baffling.
https://lh5.googleusercontent.com/-n...6-no/upload_-1


Found a suitably sized piece of hose that screwed into the left over thread on the catch can inlet, and sealed it with rtv, not really necessary.
https://lh3.googleusercontent.com/-S...6-no/upload_-1
https://lh4.googleusercontent.com/-J...6-no/upload_-1


I then cut the foam to size, and punched a whole through it with the help of a drill bit and a saw blade.
https://lh3.googleusercontent.com/-e...6-no/upload_-1



I had a huge void from removing ac and powersteering that was perfect spot for my can, soo bashed out a simple bracket while the rtv was drying
https://lh5.googleusercontent.com/-r...6-no/upload_-1


Didn't like the blue hose, was going to use some oem black rubber hose but couldn't find enough so cheap mans braided hose FTW!
https://lh6.googleusercontent.com/-m...6-no/upload_-1




And finished product, cars not running to see how well its working yet thou.
https://lh3.googleusercontent.com/-h...6-no/upload_-1




I deliberately mounted it facing backwards soo it was easy to see the level gauge and get to the drain plug but I think it came up super neat

I see one potential problem. If that hose goes deep enough into the catch can so that the end of it is completely submerged in oil, then there will be no way for pressure to vent out easily. It will have to push its way past the oil first. I would make sure the hose can't go past the top of the sight gauge or at least make a mark on the sight gauge showing where the hose ends.

I was thinking the same thing - and the fact that the can isn't vented would allow pressure to build up between the filler neck and the rear drain line, wouldn't it?

Still, I do appreciate the thought put into the setup!

It is vented, but only as well as the factory PCV system is since that is basically what it still is except with a catch can inline. Basically under vacuum it will be vented, but under boost it won't be.

The hose only goes down about half way into the can, and is the oil input side of things ie from the crank case.
Its my understanding that this will work best when there is oil over the hose that way the oil will also act as a filter as the blowby and air has to go through the oil before it can be sucked back into the intake. it also prevents the blowby skipping the can altogether as it could possibly do especially with the baffeling I added

I also worried about the ill effects having a non vented can that was only ever subject to vacuum possibly pulling straight oil up from the sump. but the standard PCV allows some venting and should maintain a low lever vacuum.
Much like if you were to plumb it staright to the pre turbo vacuum point.

I preferred to use the standard pcv point as Im sure some blowby will still get through and then it wont go through the turbo and intercooler just the intake manifold.

I really want to run this setup on my car but I can't get the -10 oil filler neck.... IRP is sold out, should I get a series 5 steel neck fabbed up?

I've used a ton of set ups, and there are a couple keys:

1. Enough capacity... I'd go for at least 1qt. if it's a track car on sticky tires that may potentially run with a completely full oil pan.
2. Being able to see how much is in the can
3. A large enough feed line and vent to relieve pressure (-10 is preferred)
4. Easy draining.

That last one is why those GReddy style cans are a pain in the ass. Once it's full you need to take it apart. I went (finally) with a 1qt. Jaz can. It's large enough, has a -10 inlet, is "natural" plastic so you can see how much is in there without taking it apart or any complicated sight tubing, and has a drain petcock, so you can get the stuff out easily. I use their radiator overflow bottle too, to make room for brake ducts.