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Old Wed, Nov-15-2017, 03:20:15 AM   #23
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Default Re: P54B32 Airbox Oil Separator - Who has info on it?

Originally Posted by Obioban View Post
GM's chief powertrain engineer on why no catch cans:

^the s54's stock system is like that of the Camaro above.

I have no desire for a catch can. The stuff people are draining is re-condensed oil vapor (which I want, as that reclaimed engine oil) and re-condensed water vapor-- which burns off when it is in your oil, assuming you get your car fully up to operating temp.

Catch cans all look clunky to me (Vince's looks the least clunky), add weight/complexity, require more upkeep, and I don't see a benefit over the factory oil separator.
You need to remember that these recycle systems are for a street car owned by a normal person which is only following standard service intervals. In this particular instance they are the best engineering option as the down-sides of not running a catch-can are over-ridden by removing the risk of engine damage from a slow reduction in oil in the system...

For those of us who are looking after our cars above and beyond standard service intervals and are looking to look after the engine as best we can the oil catch can is still optimal. Filtering blow-by and crank case vent gases prior to reintroduction to the intake tract removes products that are not required and are actually counter-productive to good combustion. This both assists performance and emissions. If you want the best for your engine this is the best option and is why they are used extensively in race applications.

I do not know why you want reclaimed engine oil? I understand that's what the manufacturer wants to make sure people who only follow set service intervals or worse people that run on longer than the set service intervals don't slowly "run-out" of oil... but for the you's and me's who actually take care of the car and monitor its performance and condition I don't see this as an issue...we will be on top of our servicing and ensure this very negligible amount of lost oil is replenished at any oil service anyway... I also don't consider they require any more upkeep than draining at a regular service intervals... in fact if you monitor the amount drained at each service interval you will be able to essentially (and somewhat agriculturally) monitor the performance and state of your piston rings and have somewhat of an early indicator on when it might be time to conduct a compression test (instead of just doing this at set intervals, or even not at all)

So now you have better performance and emissions (admittedly edging on negligible, but never-the-less real, similar in principal but not magnitude to underdrive pulleys) and an ability to monitor the state of your piston rings without requiring a compression test or oil sampling... hence allowing you to better decide when it is time to conduct oil sampling (for reasons other than bearing monitoring) and/or a compression test... which if you are someone that does this regularly it may allow you to increase the intervals to better match with when you start to notice a change in the filtered products in your catch can...

All this said... I do totally agree that they are by no means "required"... they are a nice to have... the stock setup is perfectly acceptable given it is a street car... and I think MOST people understand that, which is why I believe MOST people only look to install them when they go to a CSL box as on top of being the better option (from an engineering, no concessions made, perspective), they protect your brand new investment from yukky crank case gases... that alone may be enough for some people, just to have that nice warm fuzzy feeling that their CSL box isn't being slowly soiled...

I think Oil Catch Cans on this engine (or really any non race engine for that matter) are one of the few times where you can say there is no wrong answer... ie to have one or to rely on the stock system... both have their pros and cons and I think the differences a to negligible to matter at our level of operation (ie not high performance, top tier racing)... but from a engineering perspective the stock systems are designed for idiots that potentially don't look after their cars and catch can setups provide the optimal option but can cause problems if you are an idiot... which we are not... although street cars are for the most part aimed at the lowest common denominator...

Another example of this is the disclaimer that used to come with the CSL with regards to the Michelin Pilot Sport Cup tyres being completely useless and dangerous in wet conditions and/or with the DSC off... really simple stuff for people like us who are not idiots... but written and distributed by BMW none-the-less to capture the lowest common denominator who might buy their car...

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