[Drewster]

Originally Posted by Dr M3an M3

From my understanding, the P54 DID use a dry-sump.

I'd be curious to see how that worked, then. My (limited) understanding is that *racing* dry sumps will actually put the crankcase under vacuum, where you might even need a vacuum regulator, while some other OE setups are more or less providing an external reservoir to a stock-ish system with PCV considerations

[Dr M3an M3]

Originally Posted by Drewster

I'd be curious to see how that worked, then. My (limited) understanding is that *racing* dry sumps will actually put the crankcase under vacuum, where you might even need a vacuum regulator, while some other OE setups are more or less providing an external reservoir to a stock-ish system with PCV considerations

In the BMW AG Motorsports catalog, it shows that the P54B32 does utilize a dry sump. Man, is it a cool motor. I REALLY wish we had the kind of space that the Z4 guys have under the hood. It would be wicked to be able to have carbon ducting to vent out all the hot air that heats up from cooling the radiator/oil cooler through hood vents.


Despite not understanding German, this video was really cool, especially when it shows under the hood.

YouTube (Short URL)

[STAATS]

Originally Posted by Obioban

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...

[TboneM3]

Well said. Plus, I don't think those of us doing a catch can are claiming that it's essential, gonna make us 10 extra hp or make dinner for us. Better yet, get a cheap one so there's no downside to having an OCC. And no, I don't consider dumping the thing once or twice a year as a downside.

[Obioban]

Originally Posted by STAATS

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...

The basis of this thread was the oil separator BMW used on the S54B32-- The racing only, not ever sold to plebs, version of the S54 made by BMW. Their revised valve cover didn't allow for use of the stock S54 separator, so BMW made a new separator part (modified the M5 part) rather than use a catch can (likely a simpler solution). I don't think the statement that oil separators are for street noobs only is accurate, including the S54 specifically.

I also don't see any weight to the argument that an oil separator means you don't need oil analysis (and if you're doing it anyway, than none of those arguments matter)-- there's a TON of things that are worth monitoring via oil analysis. Everyone should be watching for elevated lead/copper, meaning rod bearings. Elevated iron likely means you have a chain guide failed or elevated cam wear, and should look after it asap. Euro cars, which everyone who has done headers/tune effectively are, routinely need head gaskets-- you can catch that in the early stages via oil analysis coolant levels. Oil cleanliness tells you the effectiveness of your air filtering solution. You see if your oil life is sufficient for your driving cycle. And, yes, fuel dilution lets you know about blowby (which you could also notice by fuel in your catch can).

Performance difference: What? There's no performance difference, at least on any engine that should be remotely on the road (not in terrible, terrible condition). This is not equivalent to pulleys (which I agree is pretty negligible).

I do agree there's not really a wrong answer. I just... don't feel incentivized to change a system that has been functioning 100% for 15 years for one that adds weight/complexity/cost with any benefit in exchange. Plus the stock separator is very cleanly integrated in to the valve cover, making for a cleaner looking engine bay

[Ramp1]

Anyone who's seen the TB's after some use sees how dirty and oily they get so the stock separator only goes so far. Will an aftermarket one work better? I don't know, but I will be putting one in when I install a CSL box in hopes that the inside of the box and the freshly cleaned TBs stay clean.

If after 10-20K miles I pull the airbox off and see it's still getting a dirty residue I will likely go back to using the stock separator. I think the assumption is that the catch cans work better. It may just be an assumption.

[Obioban]

Originally Posted by Ramp1

Anyone who's seen the TB's after some use sees how dirty and oily they get so the stock separator only goes so far. Will an aftermarket one work better? I don't know, but I will be putting one in when I install a CSL box in hopes that the inside of the box and the freshly cleaned TBs stay clean.

If after 10-20K miles I pull the airbox off and see it's still getting a dirty residue I will likely go back to using the stock separator. I think the assumption is that the catch cans work better. It may just be an assumption.

My TBs seem fine on both my 145,XXX mile s54 and my 185,XXX mile S54.

[L0ADED]

Let's not add complexity to the design. One of the best aspects of the S54 is that it is a fairly simple, elegant design and easy to work on. Adding extra stuff is just not necessary.

[bigjae1976]

I’ve used a catch can before on other motors. While I’m sure they reduce the amount of oil and stuff that gets into your intake components, it doesn’t eliminate it. I think its a waste because you still have the line that goes to your oil pan. If anything, I would think that recycled oil would not be good since it contains condensation.

F1 engines purposely burn oil. The explanation is that there is a caloric value which results in more power. The cars also get lighter by burning oil throughout the race. While the ITBs get an oily film on them, I don’t see why this is an issue unless it interferes with the butterflies opening and closing.

Then spending $200 on a catch can is insanity to me when all you are getting is a trumped up eBay unit that costs $25. But to each their own.


Sent from my iPad using Tapatalk

[Cristov9000]

Originally Posted by bigjae1976

F1 engines purposely burn oil. The explanation is that there is a caloric value which results in more power. The cars also get lighter by burning oil throughout the race. While the ITBs get an oily film on them, I don’t see why this is an issue unless it interferes with the butterflies opening and closing.

F1 engines burn oil because the regulations for additives in oil are much less strict than the regulations for the fuel used. Oil in the combustion chamber is generally a bad thing for combustion. The PCV system is there for emissions, to make sure the crankcases gasses don't go into the atmosphere where the used to be dumped.

Why it is on the P54 I have no idea. A true dry sump car doesn't need that separator and the vacuum created by the scavenge pumps in the crank case would be sucking the air out of the intake through it.