The idea of installing a catch can on a boosted vehicle is nothing new, however I rarely see Gen1 MINI's actually running one. Surprising how everyone prefers to pour Seafoam down their vacuum lines instead. Watching the puffs of smokey Seafoam rise from the tailpipes is kinda cool, but I'd rather do something to prevent carbon build-up from happening in the first place. Since MINI's use a direct injection fuel delivery, I believe a properly installed OCC should be paramount to keeping your MINI in shape. As of right now I have everything to build out the PCV (dirty) side and should have the remaining parts for the clean side in a few days.


Mishimoto OCC with extra components and tidbits

I scored the can from the NAM marketplace thanks to @morganr81 which came with the fuel line, clamps and connectors. Originally it came with a level gauge tube but one of the tube housings broke (advertised for sale w/defect) which made it perfect for my plan. The scouring pads, silicone caps and brass plugs came from a separate Amazon order that just arrived the other day. The two square things wrapped in cellophane are breather filters that each have their own elbow hose. As I test fit everything together and figure out the best approach I'll be sure to document w/jpgs. The use of an OCC is not readily agreed upon by everyone, so feel free to share your own thoughts, opinions and experiences; especially if you see me doing something completely wrong. If you have any questions feel free to ask.

 

I’m confused. The Tritec uses port injection. I won’t claim that a catch can isn’t beneficial though - several people here run them.

 

The only thing I can think of that you are doing wrong is installing the catch can. A catch can is a solution looking for a problem.

The catch can just adds more connections/hoses that can develop a leak. If the hoses aren't oil resistant they can deteriorate and cause problems. If the hoses are sufficiently strong they can even collapse under the low pressure and interfere with the proper evacuation of the crankcase.

And the catch can won't catch enough of whatever you think it will catch to make any difference. Otherwise you'd have to check it quite often (at every refueling stop for example) to empty it to prevent it from getting too full and possibly damaging the engine.

 

Think what you will but a properly installed catch can will prevent some oil from being ingested into the engine....not a lot of oil but worth the effort. I rarely catch more than a tablespoon after a thousand miles. Yes, good, oil-resistant hoses and fittings are a necessity.

 

@deepgrey correct, I should have specified, I see more Gen2's running a can than Gen1's for obvious reasons. @RockC I have seen some guys create problems with a can due to the type of can and/or how they installed it, but if done properly it will collect about 1 cup of oily mess per 3000 miles. Pouring a coffee cup full of oil (fresh or otherwise) down my intake manifold so it can bake onto my valves just doesn't sound like a better idea to me and the engineers at Porsche seem to agree. @NC TRACKRAT I agree 100%, I've seen some of the cheesy hose line that comes with some of these CC's and it blows my mind how the manufacturer is able to get away with selling such booby-traps to people, I'm attaching a good example below.

 

Below are the breather filters and knick knacks to make this thing work how I want it to. There is more stuff to do here before assembly but I have to get back to earning money now.


Breathers and elbows

good fit at the top end

1/8 brass plug to close the bottom end (there is also a dedicated drain plug on the bottom)

the pressure rated fuel line fits as it should

the elbow hoses that came with the filters are more like plastic than actual rubber

The intake bypass caps fit as I expected, the o/d of the intake junction is about 1.5mm bigger that this hose.

 

Never understood going back to this forums inception why people think a catch can is needed on a super charged system. Everyone has their own thoughts opions etc but it’s just not needed and if a 300whp plus build isn’t using one that should say something. I get some people like to tinker…. But even @Unbreakable Lump concurs

 

I won't get into a debate over pros and cons of installing a catch can on a 1st Gen R53...
But I do find it interesting that you mention installing a breather/filter.
I had done the same.
I was later told that the Mini engine is a sealed system and therefore a filter should not be used in this case.

 

The other breather for the clean side came in today so I got the can prepped and sealed with some RTV. The scouring pads are not the typical flat-wire type for a reason, I wasn't sure if I'd be able to open the can completely at the lid, so I got something that could be made to fit through the connector hole just in case; the gamble paid off. After removing the hex bolts it was clear to see that the lid wasn't budging without some serious aggression, so I left it alone. These copper scouring pad donuts are actually all one piece of wire, I found the edge and untucked it, cut the small tie-knotted piece that was keeping it in place and was able to unroll it like a sock ball. From there I just made an estimate next to the can and cut two pieces off. Any loose bits of wire fell free with ease and the longer scraps were easily removed without disturbing the rest of the portion. I'm only explaining this now to dispel any "those wire fragments are going to fly into your supercharger" suggestions. After carefully spinning the twisted pieces into the connector holes they both unravelled to make some satisfactory baffling. From there it was just a matter of spreading a conservative amount of RTV appropriately and threading it all back together...


Full, un-cut copper wire scrubber

Same unravelled scrubber after cutting a baffle piece off, the tiny clippings were easy to remove

After tightly rolling the baffle piece, it spun right into the connector hole

The end result, two pieces of copper baffling that almost run the full length of the can

 

I'd avoid running it with a breather , it will mess up your vacuum system having it vent like that , our cars are a closed system , I suggest removing the filter and running a sealed system..

 

more importantly, it prevents oil buildup in the intercooler which csn slowly bake on and slowly cut down flow and retain more heat...
imo with how our cars collect oil in the ic , a catch can imo is a must..

 

@Here2Go & @MiniManAdam I fully understand what you're suggesting, so I plan to also vent the clean side (behind the heat shield if possible) after capping off the original intake connection. I've seen pressure measurements of a few can systems and depending on the engine + can type the end result could easily be a crankcase/valve cover pressure increase.
This tends to be the case with filtered cans, don't get a can with a fancy filter. Based on typical race engine optimization I'm leaning towards increased venting to avoid the blow-by effect as much as possible. I've seen some teams drill a third hole in the valve cover just to add more ventilation and decrease internal gas pressure in proportion to their tune. The oily intercooler is not the only negative to the MINI's closed system, under heavy boost, the vacuum created by the main intake hose actually reverses the gas flow just enough to pull oily vapors down into the throttle body and onward through the system.
What's important to remember is the EPA and manufacturers designed these systems to prevent pollution and in that regard they work. Aside from that, the only other purpose the system serves is to cool the oil a bit as it flops around under the valve cover. Bad news is I have time to ponder the final install a bit more due to my belt tensioner needing a replacement, so I'll need to delay the occ install until that's done (no point in draping extra hoses over that part of the engine beforehand.) I'll post a few more pics of some test fitting as I decide where to jam it in.

 

Sh-pow! With some help from my fellow mechanics I got the belt tensioner swapped out before the weekend. If your MINI is anywhere near 100K I strongly recommend this part upgrade, it's running like it used to back in 2008 when I first test drove it!

Now for the OCC, I took a couple pics of the possible locations for install and will try a few more options after reversing the mounting bracket. The spot pictured here is really tight in terms of being able to drain it, that heat shield and manifold is in the way. It looks as if reversing the bracket will allow the can to fit right between the heat shield and the space for the oil filter housing cap. Strange, but the biggest problem is the protrusion from that plastic "firewall" that looks like it was designed to hold something in place, maybe the engineers were thinking of putting air/oil separators on these but changed their mind.

Size comparison to space available

The weird protrusion at 11 o'clock

Little to no room for draining here

The weird protrusion is wedged in the top corner of the OCC housing, I might have to grind this oddity off for optimal placement.

 

Check to see if the can fits inside of the plastic air housing, then you can plumb the hoses through a pair of grommeted holes in the plastic. draining it would require pulling the mounting screws, but it won't get in the way of changing your oil filter that way. Take a look at the photos that MiniManAdam posted, it looks like his is mounted this way.

 

I explored that option and decided I'll keep my eyes peeled for a can that's a little bit smaller/lighter. The one I got is a both bulky and heavy requiring a robust mounting solution and lots of room. I got it all plugged in though and will post the pics with schema details in a little bit.

 

The job is done! I will say that if anyone wants to run an OCC on their MINI, I strongly recommend getting one that features a threaded/removable can. I foresee the use of the drain plug to be a messy ordeal. In this case, the can will be removed on the next oil change anyway to easily access the oil filter, this way I'm sure not to forget about it. Also, the plastic wall that I mounted the can to was very easy to drill through and at the same time thick enough to hold the weight of the can with ease. After several days of checking and re-checking to make sure I had everything I could possibly need to get this done in one jump, I took the plunge this morning and got it done before lunch....

Oddly this was the best place to dedicate the mounting bracket provided by the manufacturer.

The breather filter was only a couple mm from the valve cover so I decided to run a vapor line behind the wall.

A better angle of how much space this can occupies.

The clean side actually took most of my time, trying to wrestle the PCV hose coupler out of the CAI tube was a little bit frustrating, but once I got it past halfway it popped right out. Everything worked out well here and trust me when I say, that cap on the CAI tube does not need a fastener; if that thing pops off on its own I'll be shocked & amazed.


Attached the breather to the original PCV hose here.

This angle of the CAI inlet tube cap is from behind the ram horn (I rotated the image to be right side up)


After getting all the tubes cut to length and plugged together, I slapped the IC cover back on and it stood the clean-side breather line straight up. I was able to make good use of the couplers that came with the unit, especially the T-coupler. Because the PCV valve points towards the front of the engine it's a real pita to bring the connection around 180* to the firewall, the T-joint made it simple though and the tiny rubber cap closed the unused side (although it looks like an appendage, will fix that sooner than later.) I left it cold in the garage to let all the thread lock cure down for a few hours, I plan to take it out for a warm up soon.


Install complete, the two breather filters are secure where they are and free from interference

Overall, the toughest part of fabricating a system like this is 1) getting a good occ match for the space you have available to mount it. 2) picking through all the different supporting hardware and parts to make it work. Since a lot of this extra work was my idea, I blame myself for all the extra effort it took to get this in place. There is plenty of room for improvement here and I will more than likely have the necessary upgrades on-hand when it's time the empty this thing in about 2700 miles.

 

A little late and (perhaps) out of step...

If your Mini isn't equipped with the factory/dealer installed alarm - This location may be a suitable option:


Since my Mini is equipped with the factory installed alarm; I chose to install my catch can on the opposite side within the cowl's inner wall.
It's tight but fit very well within the contours of the ABS lines. Fortunately in my case; draining the oil from the catch can is made easy by either unscrewing the the top allen plug or dipstick and extracting the oil with
a 1/8" tube attached to a syringe.
I check the contents level at every 3,500 - 5,000mi oil and filter change.
I have yet to siphon out no more than a table spoon or so at every interval.
I have noticed my intercooler boots to be much, much cleaner with very little oil accumulation.

- FWIW:
There was also mention (somewhere) that a catch can should be mounted/installed away from the engine in close proximity to high heat.
Perhaps debatable...or a mute point to some. Very few options in a Mini.

 

Yeah I originally wanted to mount inside that cowl space, but the drain plug thing and the cramped space didn't seem like a good fit; the mounting bracket for the can further complicated that location. I was also considering a good ol' fashioned air/oil separator, although they too have a drain plug, they seem much easier to mount almost anywhere, not to mention they are very compact. Interesting how you're not catching a ton of oil, I've seen an average of about 2/3 cup from user reviews across various makes and models of automobile. Looking at your setup, I notice the lines run considerably higher than the PCV valve, have you ever checked the hoses for oil accumulation? That was another concern of mine during install, I tried my best to keep the hose level without too much crazy upward direction, the one on the clean side will have to be checked in about 500 miles or so because it's setup like sink trap right now.

 

Although I would agree that's a fair observation.
I have ocassionaly pulled my cc hoses during other maintenance activities. I am not overly concerned.
But nonetheless - a fair observation.

 

Might be a little late also....I did a similar set up to Here2Go with my catch can placement but I don't have a factory alarm so I found a stud behind the hood release and mounted it there.
https://www.northamericanmotoring.co...ml#post4503355



Very similar results... about 2 tablespoons of oil last time I emptied it.
***Every now and then I have a slight oil smell in the car (outside air comes in through this compartment) and I think it is coming from the CC. Eventually I may need to track that down.

 

@bump32 that's a nice fit! The best way to curb that smell would be to run a line of silicone thread tape around everything that screws on & off, the pressure coming out of that PCV is highest during idle and it's rather significant considering the small diameter of the valve. On a quiet morning, I can hear the fumes pumping into the can while sitting at the red light.

After the first test drive post-install, everything went smooth until I came to the first red light, then the EML came on. I thought maybe I broke the return line into the sc, but after pulling the ic and peeking through the gaps, I saw it was still properly attached. Then I remembered what @MiniManAdam said about the breather on the can. So I took the filter off the can, put a hasty cap on that hose and after a couple long drives around town running errands, no EML (makes sense as the valve is designed to close under boost from the sc line); thanks for the heads-up So I dumped about 3/5 a can of Seafoam into the fuel tank and once we get closer to the next oil change, I'll dump the rest down the vacuum line to clear out the oil on the valve seats a bit. The weather just turned off the summer thermostat settings around here and the boost response from the 40*- 50* temps is extra nice after removing all the hot air injections from the PCV lines, perfect timing.

 

This is why you don't use a breather style can on A properly set up system.
The PCV system is a sealed system, therefore anything introduced into that system must also be sealed.
At least you had the ability to close it off without having to remove or redo anything.

 

@BlwnAway you are correct and if I did have to redo it, I legit would seal off that friggin' bs pcv valve tighter than snail crotch, run the can W/breather on the clean side, completely remove the drain plug on it and attach a drip line straight to the ground like it was the 1970's all over again. Since everybody else is running their perfect little "sealed systems" with cat 3 oil leaks all over the engine block, will it really make a difference to the environment if I'm being a rebel and leaving a drip or two every 25 miles? I doubt it

 

I've had a M7 can in my 2005 R50 for a few years now. I know it's not strictly necessary, but because I want to preserve as much horsepower as possible, cleaning and cooling the air sent back to the throttle body seems like a good idea. I looked up this topic because my PCV valve just went bad, and I also had to replace the spark plug tube gaskets in the valve cover (I was getting intermittent P0130 and P0136 codes, sometimes together). Both O2 sensors are new, and there are no exhaust leaks, so I began to suspect the vacuum side, and when I went to replace the spark plugs, the plug in cylinder 3 had oil on the threads. It all seems to be working fine now. There was never any smoke, just a rough idle sometimes and the annoying codes.

 

The oil used (old and new) is Liqui-Moly 5w40 Leichtlauf. This oil can easily remain in service for 4000 miles as it still had plenty of golden luster and a healthy viscosity when I pulled it out. If a thinner viscosity of oil were used, there would certainly be a lot more oil in the catch. I removed the can entirely to get good pics of what was inside (this is what goes into your throttle body, supercharger, intercooler and eventually builds up on the back of your valves in the form of well-baked oil sludge.)

I took note of some improvements and at the top of the list, the can used here is way too big, a can half this size would be better, I'm even considering an air-oil separator instead. Second hurdle is the full 180 of the intake hose from the PCV to the can, when I find a good factory formed line I'll share it here. Important to note that there was no sign of oil inside the return hose, while the intake hose almost had oil dripping out of it, a small amount is probably sitting in the line. Finally the mount, with a smaller unit, the mounting options will be better and I'll attempt to put it further back into a more "out of the way" location later this year.

As the pics show, there was a solid ounce of dirty oil that actually drained out. Between the hose, the mesh baffle and what did not drain from the bottom corner of the can, it's safe to assume there was about 1.5 ounces captured over the 3125 miles. That's roughly 2.5 to 3 tablespoons of dirty oil potentially running back into the clean side of the air intake. I can imagine how much oil is sitting in my intercooler after almost 20 years of motoring.

Used a laundry detergent measuring cap as a drain pan

This can is large enough to catch oil for about 10000 miles

The flat bottom and the inside corner retained some oil that would only come out by tilting the can back and forth

2.5/3 tablespoons of oil