BMW 3-Series (E90 E92) Forum - View Single Post - REPORT: Proof that BSH Oil Catch Can Does Not Work

RedlineMotorworks · 04-12-2011, 01:27 PM

So here's what I have to say...

You should keep in mind that NO recirculating catch can will be 100% effective at catching oil without becoming a restriction and causing back pressure. The recirculating catch can was chosen for this platform because it is emissions compliant and it does what it's designed to do at a high efficiency rate. In designing this catch can the proper testing was performed to ensure sufficient flow was available to keep the engine running properly while also keeping in mind the need to filter out the blow by. By adding things like steel wool or additional baffling you will be running the risk of creating back pressure which will ultimately cause your turbo seals to go out.

A vent to atmosphere catch-can would be 100% effective but they are not emissions compliant or road legal. There will also be oil vapor released into your engine bay and the atmosphere which can be smelled inside the cabin in certain circumstances.

The video and comments posted by the original poster simply show that the catch can is doing its job. What isn't taken into account is the many other variables such as how well the engine is sealed, the climate the OP lives in, or the driving habits of the OP, etc. When BMW or any car manufacture makes an engine, there are dimensions and measurements with tolerances. What this means is that when the piston rings seal up against the cylinders, some engines have a tighter fit than others. This may be a case where the engine is actually very well sealed.

There's no way for anyone to conclude that the catch can is ineffective from the testing that has been presented nor can we conclude that his car is one of those factory freaks where the seals are near perfect. There are over 1000 N54 oil catch cans in circulation and with several posts showing plenty of oil being removed and we along with BSH have yet to see sign of concern until now.

The best thing anyone can do is contact BSH or the dealer you bought it from directly so they can compile all the data and make the best decision on what to do.

04-12-2011, 01:27 PM	#59
RedlineMotorworks Banned 199 Rep 2,502 Posts Drives: 6.2L F-150 Raptor Join Date: Sep 2007 Location: Redline Motorworks iTrader: (19)	So here's what I have to say... You should keep in mind that NO recirculating catch can will be 100% effective at catching oil without becoming a restriction and causing back pressure. The recirculating catch can was chosen for this platform because it is emissions compliant and it does what it's designed to do at a high efficiency rate. In designing this catch can the proper testing was performed to ensure sufficient flow was available to keep the engine running properly while also keeping in mind the need to filter out the blow by. By adding things like steel wool or additional baffling you will be running the risk of creating back pressure which will ultimately cause your turbo seals to go out. A vent to atmosphere catch-can would be 100% effective but they are not emissions compliant or road legal. There will also be oil vapor released into your engine bay and the atmosphere which can be smelled inside the cabin in certain circumstances. The video and comments posted by the original poster simply show that the catch can is doing its job. What isn't taken into account is the many other variables such as how well the engine is sealed, the climate the OP lives in, or the driving habits of the OP, etc. When BMW or any car manufacture makes an engine, there are dimensions and measurements with tolerances. What this means is that when the piston rings seal up against the cylinders, some engines have a tighter fit than others. This may be a case where the engine is actually very well sealed. There's no way for anyone to conclude that the catch can is ineffective from the testing that has been presented nor can we conclude that his car is one of those factory freaks where the seals are near perfect. There are over 1000 N54 oil catch cans in circulation and with several posts showing plenty of oil being removed and we along with BSH have yet to see sign of concern until now. The best thing anyone can do is contact BSH or the dealer you bought it from directly so they can compile all the data and make the best decision on what to do.
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