[lazyninja87]

My catch can has been installed 15k miles ago and got to about an 1/8 filled and it wont fill anymore. Anyone know why? I checked over my connections today and all looks well. I also got the SES light associated with failure of the NOX sensor recently, could they be related? I like to think that I'm slowing down any future CBU issues but if my catch can isn't being filled I don't think I am. Any thoughts suggestions?

[BimmerToolRental]

I hate to throw negativity out there but catch cans don't work. They are the $15 /35HP chip resistor or the little electric supercharger that goes inline with your air filter sold on ebay.

The volume of oil vapor blow by that is happening is far greater than any tiny amount of oil dripping into that little can. Yes it does fill up over time, but its accumulating much more in your intake tract with or without the catch can.

The only way to resolve your issue is to block or remove the EGR.

[BB_cuda]

My reading here has shown varying degrees of oil collection rates. I empty mine every 3000 miles and see about 1/2". This would translate to 2.5" (nearly full) at OP's quoted 15000 miles. OP, what brand of can are you running? I have ADD-W1.

[WickedLou9]

Originally Posted by BimmerToolRental

I hate to throw negativity out there but catch cans don't work. They are the $15 /35HP chip resistor or the little electric supercharger that goes inline with your air filter sold on ebay.

The volume of oil vapor blow by that is happening is far greater than any tiny amount of oil dripping into that little can. Yes it does fill up over time, but its accumulating much more in your intake tract with or without the catch can.

The only way to resolve your issue is to block or remove the EGR.

I gotta agree. I think you often find them on cars used on the track and people have come to assume that it's because there is a performance benefit. there isn't really. The "catch can" is used to prevent oil from getting on the track with open PCV systems that vent to the air. I had one on my old MKV GTI because it was supposed to prevent carbon buildup. It didn't. Someone actually went through the trouble once to do a carbon cleaning and then install the catch can and then take pictures of the intake ports after some amount of time. Carbon built up exactly the same as it had before. There was no benefit. All you are doing it collecting water most of the time and taking the chance that it will freeze and block the lines. then you are really in trouble.

[Thecastle]

Yeah catch cans have never been shown to improve cbu, so long as the pcv is functional. What collects in a catch can isn't mostly oil, is water and fuel. If it's catching any significant amount of oil then the oil seperator isn't working right. Catch cans tend to fill with more water when it's cold out.

There can be a performance benifit to catch cans on turbo cars, as it reduces oil build up in the intercooler which can moderately improve performance by helping to maintain lower iats. Also keeping oil/water out of the intake on gasoline engines can help to increase power as oil vapor decreases octane and can cause a car to pull timing. Finally in high boost applications some catch cans have better valves that keep boost pressure out of the crank case.

None of these are the weak point on these cars. You ain't gonna get much benifit on the lightly modded d. To my knowlege here are no turbo upgrades yet, just an enlarged compressor wheel, and turning clip of the stock turbo, which probably raises us from 310whp to possibly 330+

[BB_cuda]

Installed the EGR block off and then catch can afterwards. Every little bit of oil not going into the intake can't hurt. Some collect very little and others more. The oil potentially coming in at the turbo is the wild card.

[lazyninja87]

Thanks all for the feedback. After reading everything my conclusion is the catch can doesn't catch enough oil to mitigate CBU to the extent I'd like. So I'll be leaving it installed but completing the EGR block outlined here http://www.e90post.com/forums/showthread.php?t=969420. Anyone know a good source for the block plates? I'd like to contact Jess maybe but I dont know how probable that is now

[rulonger]

Originally Posted by lazyninja87

Thanks all for the feedback. After reading everything my conclusion is the catch can doesn't catch enough oil to mitigate CBU to the extent I'd like. So I'll be leaving it installed but completing the EGR block outlined here http://www.e90post.com/forums/showthread.php?t=969420. Anyone know a good source for the block plates? I'd like to contact Jess maybe but I dont know how probable that is now

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