I'm new to transverse engines so I'm peering at the labyrinth of hoses and parts that make up the intake so I can better decide where to install my catch can(s).



I'm a little puzzled about the flow of the intake system:



1. I know from changing the air filter that the air intake is an opening on the bottom of the air filter housing,. but it then appears to go directly to the turbo. Does it then go to the intake manifold with some tube going around the back of the engine? If everything routes through the turbo, what activates the turbo - vacuum?



2. It seems that the crankcase blow-by vents from two locations on the valve cover -- one going to the turbo, another directly into the intake. If I'm installing cans to reduce the amount of oil mist, it would seem I need to installed two catch can systems -- one going to the turbo and another from the air filter to the intake. Correct?



3. Lastly, while I have had cold air intakes on other in-line engines (BMW all), I was able to route outside air to the filter. In the case of the MINI, it seems the "cold air" intake systems are essentially worthless since they draw on air already heated up within the engine compartmernt, Correct?



Thanks for helping out a newbie.

 

Get the AEM intake it’s comes with hood scoop too help draw in cold air.

as for the oil catch can.


hopefully this helps. Project mini on YouTube had a dual setup on his n14, where I have blocked off the passenger side.

 

Thanks. That helps if I choose at some point to do cold air intake.

Aa far as the catch can, my question really was the routing of the intake system not so much where to put the catch cans. I'm trying to understand what kicks on the turbo. Also, to your install, does blocking off the passenger side of the pcv system cause blockage or does all of that now flow through on the turbo side -- and if so, what if the turbo is not turning? It seems like that would invite build-up within the turbo.

 

I have no oil build in my turbo, intake hose or in my intercooler anymore. I really only tend to collect stuff more during the winter months, more due to the gas blend than anything. When I’m easier on the car I do collect stuff, but my weekends on the Dragon when I’m harder on her, I don’t. I blocked the passenger side just because that ran down into the intake manifold and I wanted to prevent the oil from getting in thar way. 30,000 miles no problems and I’m at 166,000 miles on my n14. Computer controls the boost via the wastegate and divertor valve.

 

Now if you are asking how the air flows, then fresh air is pulled in from the driver side head light, throw air filter, then maf, intake tube into turbo, then compressed and out driver side close to radiator support down to intercooler then back up passenger side into throttle body.

 

Thanks. About as tortuous a route as it appeared to be!

One more: Since you say the turbo is controlled by computer, that means the air is still flowing through the turbo just without compression and it will at least give the blow-by blocked by your passenger side plug a secondary route out of the valve cover area. Hence, having at least a catch can upstream of the turbo is the first one to do.

 

An OCC will also block the oil from getting into the manifold, and from the point of view of PCV, blocking this port is defeating the PCV function.

In my opinion, if only one OCC is to be used, it belongs on the manifold side where the majority of oil is "caught" by the PCV system --- in "most commonly used" cars. Per the Bentley manual, the manifold port is used during manifold vacuum conditions. The turbo port is used during boost. Consider your usage if installing only one OCC. I'm using a dual OCC and when draining them, the manifold can contains almost all the "oil" while the turbo can is almost dry. My car is used as a DD for a retired person with minimum boosting.

 

More info for SkipII --- as a newbie, you might appreciate the online illustrated parts list most of us use for finding part numbers and locations --- https://www.realoem.com/bmw/enUS/select Really useful for following the air flow thru the maze of plumbing. IMHO, the Bentley manual is the best service manual available and if you're a DIY'r, don't hesitate obtaining the latest version.