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Proper oil catch can setup for a road racer

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Ludachris

Founder & Zookeeper
8,053
3,072
Nov 12, 2001
Newcastle, California
So here's the deal... I've read through a number of threads with tons of conflicting info. I have a catch can with filter on top with the old way of running the lines (from the two spots on the valve cover, PCV valve replaced with a nipple, both going to the catch can). I know this isn't the right way to do it, as I have oil coming out of the filter of the catch can, making my engine bay pretty dirty. I know I need to change it, but would like some feedback on how to do it right for a road race car, not a daily driver, not a drag race car.

So now that I'll be moving to a speed density setup, what would be the right way to route the lines for the catch can? I'd like to stick with a single can, as opposed to running two cans. I'm assuming that I wouldn't have to run a line back to the air intake pipe with speed density, though I should be doing that now with a 2G MAF.
 
How you've described is exactly how I would suggest running a catchcan setup on a race car. The purpose of the more complex setup for daily drivers is to maintain crankcase circulation by keeping the original system totally intact, just adding checkvalves and catchcans.

If there is oil coming out of the breather, I would suspect a flaw in the design of the can. Does it have baffles/materials inside for capturing oil? You could try stuffing it with some steel wool (NOT recommended for other setups due to the risk of wool re-entering the system).
 
What is your reasoning for wanting to run one can vs. two? Just space/cost?

My current plans for a catch can setup include -10 AN fittings on the valve cover, probably replacing the side vent and PCV. Then run each to a separate sealed can, and back to the intake manifold/intake pipe as they were from the factory. Unless someone has a reason that this isn't needed or another setup would be better, in which case I'm all ears.

I did just find someone running 90* vents off the top off their valve cover on a 2g with no clearance issues, so this has me thinking of what the best way to weld on fittings is now. I believe Paul (even though he's not a road racer) said the 90* would be the best approach when considering how the baffles are in place.
 
Ok... I'm thinking about making a setup with two -10's off the valve cover just like you guys are suggesting. Both lines will go into one can with either one -10 or one -12 line off the top of the can recirc'd into the intake pipe.

What would be wrong with pulling out the baffles in the VC out and running the lines off the side instead of 90's off the top of the cover and keeping the baffles in?
 
Pulling the baffles out will result in a lot more oil in the catch can. I've read about a few people who don't have issues with all -12 hardware and no baffles, but most people running no baffles and -8 or -10 hardware have to empty their catch cans very often - some weekly, some more than that. I couldn't give you the full car setups for these people off hand though, so I can't tell you why some have issues and a few don't.

I would like to take the baffles out to properly clean in there, but am not sure if I want to see the welding bill to put them back in.
 
^^^ This is good and correct, but sometimes oil vapors goes into your IC pipes and turbo and you wonder WTF is this... For a serious road race car, like you Chris, I would consider something extreme... Because I assume you sit on the redline a lot and for prolong periods of time. Either 2 -12AN off valve cover to a catch can with breather, or I was looking at the pictures from Shootout at E-town, but couldn't find this one/ MAPerformance's RWD- 4G63 powered RX-7.. If someone can pull it would be fine... They had QUADRUPLE like -10AN fittings coming off valve cover to a large custom catch can with 4 filters on it...
 
And a few more.

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Just ran across this thread and I have to say that is a very nice oil catch can setup!! If you would allow us we can custom build you a combo radiator / oil catch can for a discounted rate! Here is an example of some of the ones we are currently building. Oil Catch Cans
 
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Just ran across this thread and I have to say that is a very nice oil catch can setup!! If you would allow us we can custom build you a combo radiator / oil catch can for a discounted rate! Here is an example of some of the ones we are currently building. Oil Catch Cans

Keep in mind that if you're not a Supporting Vendor you cannot mention anything to do with any business you may own or be associated with.


So is the set up in the pics on the RX7 posted by snowborder714 recommended for just a RR car?

I would think that setup would be way overkill for a road race car. That RX7 is a low 8 second RWD drag car. My guess is the engine is built pretty loose, hence the need for that much venting. That is the most extreme setup I have seen to date though.









As an update to my progress on this, my brother and I have been working with Craig (one of the Supporting Vendors) to get some custom catch cans produced. He typically makes a one size works for all can, which would be great for most people. But the club rules require that any catch can to have a 1 liter capacity, so we have to design something as Craig's aren't that big. We've been talking with him for the past two weeks and have come up with something pretty solid. Either myself or him will post up more once we finish with the design and move on to production.
 
^^^ That is true , Brian, but I've seen on few cars with PROPER catch can set-up, but very small size can, it will overfill pretty quick with every pass.. And with RR once you go thru the gears can be pretty much compared to a drag pass... I think it needs to be larger size, bu may be not with 4, but 2 lines from the valve cover.
 
I guess there are really two ways to look at this question.

1) What's the best way to vent pressure without creating a mess, which would be create as much open surface area to relieve crankcase pressure and create a catchcan that is baffled enough to not create a mess. For example, adding a baffled catch can to the system you already have. and using large lines going to the catchcan. the filter or "exit" could be relocated to avoid any mess. This should reduce or eliminate positive pressure and avoid spraying oil everywhere.

2) The other option would be to actually pull a vacuum in the crankcase (beneficial) and not create a mess under the hood doing it.

There are two "good" ways of doing this that I know of. Version one involves a setup much like that video shows where you using the turbo inlet as your vacuum source when not idling, and your manifold as your vacuum source when you are idling (through the use of check valves). I would go through a baffeled catch can first because oil droplets can cause damage to the compressor blades when they're spinning at 100K rpms. You also don't need three 5/16th lines to do this. Air moves pretty quickly through a single line.

The other way would be to use a venturi tube in the exhaust to pull the vacuum. Typically this system also includes a catch can which reduces the amount of oil that gets pulled into the exhaust system. What ever oily residue is in the air is sent into the exhaust and burned instead of being circulated through your turbo, intercooler and intake manifold.

If you have a properly baffled catch can, you'd also be able to allow the oil to drain directly back into the pan, avoiding the need for constant emptying.

The third option would be to have a dedicated vacuum pump... but this seems like overkill ($$ and time) for a horsepower or three.
 
The other way would be to use a venturi tube in the exhaust to pull the vacuum. Typically this system also includes a catch can which reduces the amount of oil that gets pulled into the exhaust system. What ever oily residue is in the air is sent into the exhaust and burned instead of being circulated through your turbo, intercooler and intake manifold.

Yeah, my engine machinist was telling me about this. Here is a link to some muscle guys doing it. Crank Case Evacuation - FordMuscle.com Forums
 
Yeah, my engine machinist was telling me about this. Here is a link to some muscle guys doing it. Crank Case Evacuation - FordMuscle.com Forums

I'm running this setup on my car, if you guys want I can can post up some pics. I haven't been able to the push the car really hard because its a brand new motor and my seat brackets need to be modified so I can drive the car. I have heard a lot of great things about them and they are supposed to suck some serious air.
 
I'm running this setup on my car, if you guys want I can can post up some pics. I haven't been able to the push the car really hard because its a brand new motor and my seat brackets need to be modified so I can drive the car. I have heard a lot of great things about them and they are supposed to suck some serious air.

I wouldn't mind seeing some pics of your setup.
 
I don't use a catch can with the exhaust evacuation venturi, maybe in the future. Right now I have the PCV hooked up to my SMIM and then the hose for the exhaust venturi is hooked up to the baffled port on the side of the valve cover. The venturi is welded into my downpipe after my wideband sensor. Its a very simple set up. Ill try and get some pictures when I see the car on Thursday.
 
Hey guys.... as Brian mentioned, we (him, Eric, and myself) have been working on a larger capacity dual-inlet version of the filtered cans I make, for use in road racing and other areas where rules and/or conditions require more flow and larger oil storage volume.

As with the standard cans, the filters in these have only .5 to .75 psi of pressure drop and can remove particles below 1 micron. But with dual inlets, the flow is split across twin filters for even less flow restriction under severe applications. These will have 1/2" NPT inlet and outlet ports, internal baffling, and the same sight glass as their little brothers. The total calculated volume is 1.22 liters...if you were to plug the outlet, fill them full and saturate the filters for some reason, it's probably a little over one liter.

Here is a CAD rendered image of where we are with the cans at this point:

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And a 3D VRML model that you can spin around and look at:

http://www.jcsautomation.com/temp/el_vrml/el_can_a.wrl

You can view it in a web browser with any vrml plugin. I use IE with Cosmo, which you can download for free here:

http://cic.nist.gov/vrml/cosmo/CosmoPlayer.zip

*************

For Brian and Eric's application, these are separate cans welded together. (not sure on the mounting bracket yet). The "off-the-shelf" cans will come with a generic mounting bracket(s)...but I'm interested in getting your feedback on that as well as the inlet/outlet arrangement before any final decisions are made.

I don't want to discuss any specifics on pricing, availability, etc. here; just get some discussion going and some feedback. I'll post something up in the vendors forum once we get to the point of actually producing them, or you can PM me if needed.

*************

For those of you that don't know, here is a thread with more links to where all of this got started. ;)

http://www.dsmtuners.com/forums/vendor-announcements/354353-filtered-catch-cans.html



(Chris...if you see this, please PM me.)
 
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i also wouldnt mind seeing this if you could get some pics and like stated above me some links or point me in the right direction of the parts you used. I have been holding off on buying a catch can for this very reason all my buddies who have one still have a mess even if they have it hooked up correctly (in their eyes :tease: ) So all info on the subject would be much appreciated thanks in advance.
 
The other way would be to use a venturi tube in the exhaust to pull the vacuum. Typically this system also includes a catch can which reduces the amount of oil that gets pulled into the exhaust system. What ever oily residue is in the air is sent into the exhaust and burned instead of being circulated through your turbo, intercooler and intake manifold.

Not to be a noob (which I am in a lot of areas), but...
Are there any valid concerns, that exhaust gases would seep back to the crank case in certain situations with this setup?

I am reading that thread now, my question might be answered there.
 
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