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Notes on the ProVent 100 oil separator in the M140i

2K views 3 replies 3 participants last post by  tyusaf 
#1 ·
Hi. I wanted to write a post about my experience putting a ProVent 100 oil separator into the crankcase ventilation line on my M140i.

This is the part I'm talking about: .


It is an alternative to several catch-can options that exist. Popular choices are
* Mishimoto: * BMS: * Williams Performance:
The problem they all try to solve is removing the small amount of oil that escapes the engine's crankcase and has to be fed back into the intake air via a crankcase ventilation hose. This escaping oil has then to pass through the turbo and the intercooler, which isn't good for them. Engines have baffles inside the crankcase to catch as much of this oil as possible. Those in the B58 are known to be very effective. Nonetheless, anybody who has seen the inside of their charge pipe knows it is not perfect.

For those interesting in the engineering, the best article I have come across is this one: .

Additionally, the SAE have produced a report comparing many different types and models of catch cans. Their conclusions are
* There are two performance factors that matter: 1) how much of the oil gets filtered/caught 2) how little they affect the pressure in the ventilation line. In other words, to do well, a catch can has to filter out lots of oil without causing a pressure build up.
* The absolute king is a model called the ProVent 200. Unfortunately, this is device the size of a small dog. It would never fit in an F-series BMW, and is really designed for diesel 4x4s such as Land Rovers.
* A half-size model, called the ProVent 100 comes not far behind it in terms of performance. It is about the same size as the catch cans mentioned above. It's bigger than a coke can but it's smaller than a pint glass. You can see exact dimensions in the drawing above. The SAE report states that its performance far outstrips the conventional catch cans. It works using a paper filter, much the same as a normal engine oil filter. In contrast, most catch cans use a wire gauze, similar to a brillo pad, which presents a smaller area for filtering. For that reason, the ProVent removes more oil with less effect on pressure. If this weren't enough, the ProVent 100 is about £70 whereas catch cans can are between £200-£300.

This SAE paper and the price difference convinced me to try to fit a ProVent 100 in my car.

For anybody interested, the reference to the paper is
Golkarfard, V., Subramaniam, R., Broughton, J., King, A. et al., "Comparative Performance of 12 Crankcase Oil Mist Separators," SAE Int. J. Engines 12(1):5-13, 2019,
doi:10.4271/03-12-01-0001.


There are a few options as to where it fit it.
* Above and to the side of the turbo on the wheel arch. The Williams Performance catch can does it this way.
* Inside the air box. The BMS catch can does this. It only works if you also have the BMS air filter.
* There is small space *under* the intake. This is the option I went for. It's best seen with a picture:


The advantage of this fitment is that it runs very close to the existing PCV hose. For that reason, you can T-off easily from it. I did the following:
* Bought a spare PCV hose on ebay and cut it. Routed the cut ends through the provent. I actually used a 45 degree elbow to extend one-end and help make the bend but I think, had I cut the PCV hose in the right place to start with, that would have been unnecessary.
* Wrapped some aluminium heat insulation around anything close to the turbo.
* Note, there are left-hand and right-hand versions of the ProVent (with different part numbers). The difference is which way the inlet and outlet connections line up relative to the mounting lugs. I bought the wrong one and ended up cutting off the mounts. I got away with it because the fitment is so tight under the intake that there is literally nowhere for the device to go. Nonetheless, for a professional fitment, you want to think about getting the correct part and fabricating a small bracket. The part of the car body supporting the bumper runs just below and to the side, so you could rivnut a bracket to that.
* Attached ~30cm section of hose pipe to the bottom of the provent. This is closed off and acts to catch the filtered oil. You can just make out the hose in this pic -- it hangs down to the front rollbar -- although apologies for the poor quality:

This is the trade-off you get with the ProVent. Because the 'can' is used to hold a filter, you get good filtering but no capacity for holding the filtered-out oil.

I still need to get a clear idea of how often it will be necessary to take off this catch-hose-pipe to drain it. After 2000 miles with the the ProVent in the car I took apart the whole thing to have a look. There was almost no oil at all. The filter media itself was still mostly white, so not even close to saturating. This is some evidence that the B58 PCV system is very effective at separating oil _before_ it reaches the PCV hose. That said, those 2000 miles were mainly motorway driving at low revs with low boost pressure. In that scenario, the car uses a different strategy to deal with crankcase gases. All I can say is that, for daily driving, you'll hardly ever need to empty it. Might be different if you are tracking it.

All in all, I'd recommend the ProVent for anybody considering a catch can in their car. You can see the final fitment from this pic. It is very discreet.
 
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#3 ·
Cheers. It's a shame nobody makes a ProVent kit for the F chassis. I managed to get it fitted but don't have the engineering skills to make a really professional job of it.
 
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