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      04-21-2010, 09:55 AM   #82
Alpina_B3_Lux's Avatar

Drives: Audi R8 V10, BMW 530d xDrive
Join Date: Feb 2008
Location: Germany

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2009 335i  [4.45]
REVIEW: ar design oil catch can

16. AR Design oil catch can

Ever since I started modifying my car, I have been concerned with its long-term reliability. Some modifications such as the additional oil cooler or even the upgraded intercooler, while enabling the engine to deliver its power consistently and without heatsoaking, also alleviated the thermal stress on the turbos and therefore contribute to its longevity. However, I learned that more or less all engines suffer from so-called "blow-by" gases which are excess gases that leak from piston rings during the combustion process and get back into the engine crankcase; from there they are vented (by crank case vents) back into the intake system of the engine to be combusted again. That wouldn't be so bad, but the blow-by also contains oil from the crankcase, and this is the real problem - the oil coats the intercooler (thus decreasing its cooling efficiency), the intake valves and other engine components, impacting their performance negatively.

Now, this oil should be caught before it creeps everywhere, and this is commonly done by a so-called oil catch can ("OCC"). Its function is to filter the blow-by gases and to extract the oil from them, retaining the latter in a container that is (ideally) easy to drain.

For quite some time, Riss Racing was more or less the only option for an OCC that was specifically adapted to our engine. However, from what I've read on this forum, the quality of this product was only very mediocre and it had a tendency to leak all over the place, due to the cheap components used in its construction.

As I had so far had excellent experience with other products from ar design, I was glad to learn that Andrew was developing an OCC for the N54. At that time, other competitors (such as the BSH OCC) were not on the market yet, and in my opinion the use of a real 5 micron filter instead of just some steel wool for filtering was a superior solution. Therefore I jumped on the group buy that was organized for this OCC. The price is admittedly not very low (list price is 229 USD), but I am happy to pay more for a quality product that fits correctly than throwing some stuff together myself and be finally unhappy because it does not work right. An additional advantage of the OCC from ar design consisted in the fact that they offered the possibility to mount it on the passenger side in the engine bay, which was necessary in my case as due to the STETT cold air intake and charge pipe I did not have enough space for the OCC on the driver's side.

With some delay, the OCC arrived and was excellently packaged in a big cardboard box. Upon unpacking the various items, I was immediately aware of the heavy, confidence-inspiring solidity of the OCC. Also, the mechanism to remove the filter and drain the oil is really easy and obvious. That was clearly no cheap ebay-like item but a thoroughly engineered solution. All mounting brackets for the passenger side location were also provided. Here's a photo (not mine, I hope the forum member won't mind) of what the components look like once unpacked:

As always, I had the OCC installed at Daum Motorsport and from what they told me it was no problem at all, and they confirmed that all components seem to be of very high quality. It IS a tight fit, and the OCC is quite close to another hose but without actually touching it. However, it does fit into the engine bay, and the mounting brackets provided by ar design had the right size. For additional insight into the installation procedure, I would recommend having a look at
Former_Boosted_IS' DIY of the BSH OCC, as the install is pretty similar.

Once in the engine bay, the OCC blends in very well and if you wouldn't know it, you could think it's an OEM part. It's also easy to access, you can see the reservoir window (i.e. how much oil is in the OCC) and the oil can easily be drained in that position, without having to demount the whole OCC. Here are two photos of what it looks like after installation:

Photo from the side:

Photo standing in front of the car:

Well, not really much to say here! It is properly mounted, it looks great, and I have no indication that it does not do what it is intended to do. After some thousand kilometers I will drain it and see how much oil it has collected, and update the thread here with the results.

Problems / disadvantages?
The only two disadvantages could be that (i) it's not cheap (but for me it's worth the amount I paid) and (ii) it's another non-OEM item in your engine bay. However, as these were no real factors for myself, I can happily ignore both.

In summary, the ar design OCC is a high quality product and I can recommend this to anyone who is interested in the long-term reliability of his engine.

Audi R8 V10; sold: BMW 335i