The Definitive OCC thread; aka Oil Catch Can, Oil/Air separator

tchuck said:
Paging Jumbo. (Tap tap tap) Is this thing on?
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I'd be cautious about that approach for three reasons.

First, the diameter of the barbs is as small as they get on both inlet and suction lines. Might be ok for Naturally Aspirated but definitely not the higher pressures of FI.

Second, I believe there are actually baffles in the valve cover prior to the PCV and vent outlets to control the flow of gasses. Not sure how they would impact the catch can system you have outlined.

Third, the center hose you propose tapping is the avenue for which the two valve covers equalize pressure relative to each other. If you put a breather in that line and cap the normal outlets it is possible to have two different pressures in the valve covers. Couple that with the small diameter of the center barbs and I'm not really sure what the impact would be.

2010fx35 said:
Uh, can someone explain what this is exactly? (dumb it down)
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It's an oil catch. Usually the PCV system (see first post) sucks oily gasses back into the motor to be burned. Along the way the oily gas leaves a trail of sludge inside your motor. This can catches that junk and stops it from sludging up your motor.
 
jumbosrule said:
I'd be cautious about that approach for three reasons.

First, the diameter of the barbs is as small as they get on both inlet and suction lines. Might be ok for Naturally Aspirated but definitely not the higher pressures of FI.

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Yeah, the small barbs worry me a bit, but then again I wonder just how much "flow" we are talking about here. Is your concern that the small lines might impede flow or that they will clog more easily? I have no plans to step up to FI with the FX, so this will be a purely NA catch can design.

jumbosrule said:
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Second, I believe there are actually baffles in the valve cover prior to the PCV and vent outlets to control the flow of gasses. Not sure how they would impact the catch can system you have outlined.
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I don't see any baffles...
VQ35DE%20no%20valve%20covers.JPG
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jumbosrule said:
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Third, the center hose you propose tapping is the avenue for which the two valve covers equalize pressure relative to each other. If you put a breather in that line and cap the normal outlets it is possible to have two different pressures in the valve covers. Couple that with the small diameter of the center barbs and I'm not really sure what the impact would be.
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Can't the pressure from the two sides equalize inside the catch can? It's not very clear in my sweet bootlegged MS Paint diagram, but there is no breather. Just a dual inlet/single outlet catch can.

---------- Post added at 11:41 PM ---------- Previous post was at 11:32 PM ----------
turbocad6 said:
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I just read the whole thread & one thing I noticed that doesn't seem to be recognized is that the 2 vacuum sources used in the factory set up are NOT redundant. they are 2 completely different types of vacuum sources & play a big part in your catch can set up in which is used & how.
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That's a good call. Would you agree that a higher flow intake system would proportionally decrease the effectiveness of the intake snorkel vacuum location?
 

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turbocad6 said:
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the intake tube pickup side of things sees almost no oil vapors really in comparison. remember it's really about venting the crank case, the whole oil deal is just a side effect. you don't want to try to catch oil for no reason while at the same time causing higher crank case pressures without even realizing it. you really should not eliminate the existing pcv circuit, engine vacuum & all, non restrictive filtering inline like most catch cans are is ok, but killing it & then trying to just run a sealed catch off the intake tube alone will actually do more harm than good, you'll start to find oil leaks eventually because of less than adequate crank case ventilation.
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That makes sense. Probably not worth the risk just to save a couple hoses. Thanks for the good advice.
 
raymond said:
Or put 2 in and buy an extra. Perrin isn't on of the cheapest and such things aren't sold very easy here.
It's all about the money.......!! :wub:
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I'll just Bump this, cause with all that reading material you guys dropped here the last 24 hours this questions is easaly forgotten :laugh:
 
turbocad6 said:
...the intake tube pickup side of things sees almost no oil vapors really in comparison. remember it's really about venting the crank case, the whole oil deal is just a side effect....
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When cleaning out the upper plenum before installing my original oil catch, there were oil tracks in from both the lower plenum barb as well as through my intake tube and the throttle body One did not seem to be significantly more dirty than the other. Of course, we are talking about 80,000 miles of use so I guess both of them could have been as dirty as they were going to get.

The fact that the two vacuum sources are different really shouldn't matter unless the hose fittings or catch can system components are restrictive. Since the crankcase has positive pressure, a vacuum source isn't really necessary - it's simply helpful. If the fittings in the PCV or catch can system are restrictive and limit the rate at which pressure increases or decreases then eventual oil leaks are a likely outcome. If the fittings or system components are not restrictive, then it really doesn't matter if you pull your source from either place (or at all, with a breather).

Tchuck - you are right about the baffles - remove concern number 2 from my list!

Ray, if having a breather is going to make it impossible to pass emissions testing for you, then going to a vacuum line sounds like the right way to go. I'd go with two cans, one on each side. One inlet from valve cover, one outlet to vacuum source x 2.
 
jumbosrule said:
Ray, if having a breather is going to make it impossible to pass emissions testing for you, then going to a vacuum line sounds like the right way to go. I'd go with two cans, one on each side. One inlet from valve cover, one outlet to vacuum source x 2.
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Yeah would that have an effect on the Emmisions....?? Cause with the whole set-up i think emmisions ill already be a bitch for me :err:
And as i understand it will you should keep the hose diameter at least the size what oem has....or maybe bigger but not smaller....right??
 
Thinking about doing the two catch can, with one on each side system. Only thing I'm worried about is the correct sizing for the driver's side.

I plan to get 3/8 in x 1/4 in barbs, 1/4 in filter aka OCC, and 3/8 in fuel hose. This should work on the passenger side I think, but will this also fit the driver's side using the assumed locations based on Brad's diagram for the dual OCC single inlet/outlet?

Or maybe just do the passenger side only as that could do enough of the job, and be much simpler.
 
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I'm getting into this thread late here, but it looks like the push is for catch-cans instead of air-oil separators. AOS is a more elegant no-maintenance design and makes more sense for street cars. Catch cans may be cheaper and easier, but they are a little more suited for race cars.

I use a Crawford AOS on my Subaru daily driver, which I also run at the strip and track. I get a ton of blow-by running 26psi of boost and E85 fuel and have been quite happy with my AOS. The Crawford units are pretty cool too, since they are heated which prevents condensation. Looks like they offer a universal one here.
 
does the overall practicality of this air/oil separator justify its $385 price tag? seems a little steep. this quote is from Jumbo:

Now obviously the manufacturers don't consider this to be a threat to the long term reliability of the car. Yes, it's a little messy over time but there is no immediate danger to the car or any of the systems. After a lot of miles, the intake would need to be cleaned out. Not doing so would begin to rob you of efficiency (mpgs). So installing a catch can on a stock VQ engine is only going to be a "nice-to-have". Not necessary, but appropriate for FX enthusiasts who want to go the extra step for their car.
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since it's a 'nice to have' and not a 'necessary' mod, i would rather get a nice set of HFC's for that price.
 
Gonna do mine today! Got all the fittings, clamps, and hoses. I got the clear hose that looks like the crappy stuff, but it's reinforced and I can't even squeeze it closed with my fingers. Only thing that worries me is that the air compressor filter I'm using to catch the oil says no synthetic oils because it can build up too much pressure. However, I think this is just because the filter can't take it, which I have removed anyway. Only thing is it says to read the manual, and there isn't one, so I haven't figured out how to use the bottom drain.

Final price for everything, including 10 feet of hose: $29.44, all from Home Depot.
 
Nice, Stu - definitely post up some pix!

I've actually started on my next OCC design (let's call this revision number 6). The box I have with the brass breathers allows too much vapor through the breathers under full boost. I have a thin film of oil over everything in the bay. Of course, I wipe down the bay about once a week so it never gets terrible but still - I would prefer not to eject oil into the atmosphere.

Since my catch can was custom made and it didn't do the job I requested, the shop completely refunded my money and I am now going to use two independent catch cans. As of today, I have a working system but it is only temporarily mounted. The plan is to make a custom mount that holds the cans at an angle just for visual effect. The catch cans I bought this time came from a Corvette application. Got two silver cans:

http://www.eliteengineeringusa.com/Catch_Can.html


Will post more when complete but this time we will route the suction lines to before the turbo, after the air filter.
 
Nice! I'll go take some pics now. I had to modify mine a bit because the drain was totally random at whether it wanted to be open or not so I just plugged it up with some RTV sealant and will unscrew for draining. Also need to drill out my mounting points, but I made some pretty clever mounts on the OCC.
 
Guys....I saw a nice Weapon-R catch can for the G35 on ebay...think this will work fine with the FX? Or is there a particular brand I should go out and get?
 
wlvrn97 said:
Guys....I saw a nice Weapon-R catch can for the G35 on ebay...think this will work fine with the FX? Or is there a particular brand I should go out and get?
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Those universal cans are fine. Only thing to watch out for is if the hose it comes with is of good quality(the hose pictured here looks just like the "reinforced" hose I chose to use), and I know Jumbo was a little concerned with the fittings on the view tube on the left.

weaponrcatchcan.jpg
 
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