What is a benefit from an oil catch can?

I kind of know the general point of installing one. I have cleaned my upper /lower plenum and every time I clean the lower plenum there is tons of oil there. So the point of a oil catch can is to catch all that oil before it gets to the lower plenum. I might be wrong or not. But if I am I'm sure other more knowledgeable members will correct me..
 
Rubare said:
I kind of know the general point of installing one. I have cleaned my upper /lower plenum and every time I clean the lower plenum there is tons of oil there. So the point of a oil catch can is to catch all that oil before it gets to the lower plenum. I might be wrong or not. But if I am I'm sure other more knowledgeable members will correct me..
Click to expand...

That's it - you got it. Here's the reason WHY.

As your pistons pump up and down and the valves open and close, the seals that isolate them from the cylinder walls are not "perfect". At higher RPMs, there is a certain amount of "blow-by" gas, which contains a little bit of air/fuel mixture, plus the oil that lubricates all of those moving parts. If you have a head gasket leak, then you might get coolant in the catch can as well. The valve covers provide a seal to capture the blow-by gasses..

The OEM design of the Valve Covers provides a way to remove this contaminated gas mixture, by sucking it out of the valve covers. On the driver side, there is a valve cover outlet that exits just below your throttle body. That outlet is connected by a tube to your intake pipe. When air is being sucked into your engine, there is also the same sucking force on that hose, which pulls that blow-by gas into your plenum to be burned in the cylinders. If you remove your plenum top, you will see the inlet from these hoses is very dirty and oily - this is the absolute DEFINITION of engine sludge.

On the passenger side valve cover, the outlet is called the PCV, and it is connected by a hose to your intake plenum - also providing suction. The two valve covers are also connected together by a hose just under the front of the plenum, to make sure they are at the same working pressure.

An oil catch can is just a filter in line with those hoses, made to separate the contaminants from the air. Eventually these catch cans fill up and must be emptied or you risk sucking the contents of the can into the plenum. I empty my can at every oil change. Here is a photo of what came out of my catch can from only TWO empties. This is only about 6000 miles! I feel pretty good about NOT burning this crap and improving my emissions. I take this bottle to a jiffy lube and let them throw it away properly.

IMG_5956.jpg

There are pretty much five different options out there for you that I have listed from worst to best in terms of oil catch performance:

5) Don't add a catch can. Yes, they will keep your engine cleaner longer and that's a good thing but obviously the OEM engineers know it's not necessary. You could just clean out your plenum once a year with some Seafoam or by taking it apart and cleaning it. The first time you do, you will be surprised with how bad it looks in there. No catch cans are perfect and will still allow some of the gas to dirty up the plenum over time.

4) Add 1 catch can on only the passenger side (PCV) hose. The PCV is a valve that only allows flow in one direction, so sometimes it is closed. You will still need to clean out the plenum - but less often than the OEM setup.

3) Add 1 catch can on only the driver side hose. Since the two valve covers are connected, this will provide decent benefit. However, when the PCV is flowing, that air will not be filtered before returning to the plenum. You will still need to clean out the plenum - but less often than the OEM setup OR if you went with the PCV side catch.

2) You can do one catch can with TWO inlets (one from each valve cover) and then use only one suction line - allowing you to "cap" the second suction line no longer being used. (this is the option I went with).

1) You can do two catch cans - one in line with each suction hose, providing full filtration of both sides.

Plenty of threads on this topic also. Two of them from yours truly!

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If you are going to get one - I really do recommend the Saikou Michi Corp brand that I ended up going with. It is the same price as all the decent ones out there, but you can customize it for your exact application with no extra charge. One or two can inlets, any size you want, types of fittings, mounting hardware, etc - great deal IMO, the best I found for a catch can.

The Saikou seems to be the best option because you can customize it. If the fittings are too small, then it becomes a restriction and doesn't remove the blow-by like it should. The Saikou is great for performance, but if you want my opinion on the SEXIEST oil catch out there, I think it's from here:

http://www.42draftdesigns.com/categories/products/catchcans.html

There are some features on there that are a little overkill - but hey if I could have justified the price of this one over the Saikou - I would have this one or the ARC catch instead. Just can't justify $400 for the ARC can:

http://www.intensepower.com/noname5.html
 
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If you want to know everything about them and the best way to utilize one, check out Jumbo's threads. He did A LOT of research and even custom designed his own catch to be as good as possible.
 
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