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Correct installation for Catch can rb25det

IM-32-FK

By IM-32-FK,
in Engines & Forced Induction

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IM-32-FK Mentor

IM-32-FK

Posted
Posted

Hey all I’ve recently decided to install a catch can and want to know if the setup I marked in the picture below is correct. So pretty much you just “bridge” the catch can between hose that goes from pre turbo pipe to the rocker cover? 

Which catch can is also better - the baffled ones without the little air filter on top of it or the ones with the little air filter on top of it?

is a three port catch can really necessary? Because all it does is keep the oil out of the little hose that goes between both rocker covers? If i do go three port, is the setup marked on the pic correct?

finally, does anybody know the size of the rb25det rocker cover breather hose fitting in case I need to change the fitting on the catch can to match the rocker cover fitting. Thanks 

CE3B9D41-45D0-4ADF-B82B-50A93FF4BA9F.jpeg

74BB0626-4FEA-4DF9-896F-B57DF6B21F74.jpeg

IM-32-FK Mentor

IM-32-FK

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3 minutes ago, KiwiRS4T said:

The first question is what is the function of your catch can and then the rest will follow.

But catch cans should not vent to atmosphere, should be baffled and at least 2L

Function is I want to keep oil out of my intake and intercooler piping!

So why isnt it good for them to be vented to atmosphere? All I can think about is that will be decrease pressure and cause a vacuum leak.

also by 2L do you mean a 2L catch can container? Does it really matter how much volume the catch can could hold, besides having to drain the oil less frequently with bigger catch cans?Thanks

Murray_Calavera Mentor

Murray_Calavera

Posted
Posted

Venting a catch can to atmosphere is illegal, if that matters to you. Having it plumbed back into the intake, the vacuum helps the catch can work better. 

Venting a can to atmosphere won't cause a vacuum leak. 

Some motorsport events require the catch can to be a minimum of 2L, I can't think of any other reason to use 2L other then more frequent changes as you said. 

KiwiRS4T Grand Master

KiwiRS4T

Posted
Posted

^^^what he said.  You want it baffled because that will help to ensure most of the oil stays in the can rather then get recirculated through the intake. Venting to atmosphere can also result in unwanted smells in the cabin.  And it works better if not vented. If you are not going to track it and you don't have a big problem you could have smaller  than 2L but be aware that some of the products you see on ebay turn out to be ridiculously tiny when they turn up in the mail. If you don't have a major problem then you can pipe both the cam covers in one hose to the catch can.

Dil-Dog Collaborator

Dil-Dog

Posted
Posted

This is my personal set up... its a non return vented to atmosphere set up, which is the cleanest possible way for your engine. All of the returns and holes have been blocked. U can get -10an press fittings from Raw Brokerage and the elbows and such anywhere like amazon.

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  • 2 weeks later...
skylinecouple Experienced

skylinecouple

Posted
Posted

Wow, that went downhill fast. I haven't been on here much but really miss the respect.

 

Anyhow, for a simple connection just run a 16mm hose off the pigtail hose that goes to your inlet. Run some wire inside the short pigtail shaped hose and you will find a restrictor. Deleting the restriction is one of the reasons people have too much oil being sucked in to their air/oil separator. On a stock turbo too much oil fumes is not a problem. Once you add a bigger turbo obviously there is more suction, therefore more oil being sucked into the inlet, separator/catch can or not. The restriction must stay in place.

Connect this new hose to the inlet of your oil/air separator. Now connect the the outlet of your oil/air separator to the intake. Done. Hardest part is finding space in the engine bay. Also, notice the use of the words 'air/oil separator. Not catch tank. 

 

Yes, I know people will roast you for not doing a search but we are all here to help. As my Old Man used to say, 'not asking questions is what makes you an idiot'.

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