[Tatoon]

Hello I was wondering if anyone has tried these cheap ebay occ. My concern is that it looks like these products don't include the tubing. Let me know if anyone has opinions. I just did the cleaning and for a 200$ occ I rather just scrub them valves.

P. S. I didn't search...

[Jeff@TopGearSolutions]

Since you didn't search that explains a few misunderstandings.

An OCC won't keep your valves from getting gunked up. It may only reduce the gunk slightly. 90% of the gunk is caused by the direct injection of this engine.

What the OCC does do is keep oil out of the intercooler and charge pipe. It also aids slightly on reducing build up on the valves.

As far as Cheap Ebay OCC, well, I'm not sure which you are referring to but "Any old OCC" will not work, on this platform.

This PCV system requires a certain amount of throughput and if you bottleneck the system it is not good.

Stick with a proven OCC.

[Mike@N54Tuning.com]

There is a cheap knock off of the BMS OCC floating around which may be the one you are referring to. Its hoses don't fit right, bracket doesn't fit right, it doesn't have a good ORING seal system on the can itself, and doesn't have a drain plug. I can't tell you how many people have tried to contact me to buy just BMS hoses and brackets, which BMS won't sell, because they know they are just going to be used for the knocked off OCC. So do yourselves a favor and buy the real deal.

Mike

[jwzimm]

Originally Posted by Jeff@TopGearSolutions

*snip...90% of the gunk is caused by the direct injection of this engine.

Hey Jeff, can you explain this more? I do not see how direct injection can directly cause carbon buildup in the intake ports. While it is true that in a direct injected engine there is no fuel wash on the ports as you would get in MPFI; the direct injection of fuel into the combustion chamber should not directly lead to carbon buildup. You do get a degree of valve overlap in the combustion cycle but the scavenging effect of the exhaust gasses leaving the combustion chamber combined with the inrush of air from the turbocharged air ensures that not much combustion products end up going into the intake ports.

Another point to this is that it has been seen in the N55 engines that the carbon buildup phenomenon has been greatly reduced with the new design of the engine. Several of us have gone in to clean our intake ports only to find a very small amount of carbon dust in the ports and nowhere near the buildup the N54's are seeing. In researching the N55 design changes one of the biggest systems that was changed was the PCV system. They went away from the N54 cyclonic oil separators to a perforated plate oil separation system. They also changed the injection point of the PCV system gases into the induction tract.

It is my understanding that the buildup being seen is a result of oil vapor and residue being allowed to coke on the hot intake ports and valves. If you remove and/or mitigate this you will virtually eliminate this buildup. A properly designed oil separation system accomplishes this. The problem is, most aftermarket oil separation systems are not capable enough and do not result in efficient separation and capture of the oil vapors.

[Jeff@TopGearSolutions]

Originally Posted by jwzimm

Hey Jeff, can you explain this more? I do not see how direct injection can directly cause carbon buildup in the intake ports. While it is true that in a direct injected engine there is no fuel wash on the ports as you would get in MPFI; the direct injection of fuel into the combustion chamber should not directly lead to carbon buildup. You do get a degree of valve overlap in the combustion cycle but the scavenging effect of the exhaust gasses leaving the combustion chamber combined with the inrush of air from the turbocharged air ensures that not much combustion products end up going into the intake ports.

Another point to this is that it has been seen in the N55 engines that the carbon buildup phenomenon has been greatly reduced with the new design of the engine. Several of us have gone in to clean our intake ports only to find a very small amount of carbon dust in the ports and nowhere near the buildup the N54's are seeing. In researching the N55 design changes one of the biggest systems that was changed was the PCV system. They went away from the N54 cyclonic oil separators to a perforated plate oil separation system. They also changed the injection point of the PCV system gases into the induction tract.

It is my understanding that the buildup being seen is a result of oil vapor and residue being allowed to coke on the hot intake ports and valves. If you remove and/or mitigate this you will virtually eliminate this buildup. A properly designed oil separation system accomplishes this. The problem is, most aftermarket oil separation systems are not well designed and do not result in efficient separation and capture of the oil vapors.

Sure, a traditional Port Fuel injection car has fuel spraying into the intake tract and thusly spraying over the intake valves, cleaning them.

A direct injection car houses the injectors in the combustion chamber so no fuel sprays over the intake vales and by no accident they don't get cleaned.

As a result, since the intake valves are not cleaned by fuel, carbon deposits that are worked up from the combustion process land on the intake valves.

Only a small portion of intake valve build up is from oil vapor.

[jwzimm]

Originally Posted by Jeff@TopGearSolutions

Sure, a traditional Port Fuel injection car has fuel spraying into the intake tract and thusly spraying over the intake vales, cleaning them.

A direct injection car houses the injectors in the combustion chamber so no fuel sprays over the intake vales and by no accident they don't get cleaned.

Only a small portion of intake valve build up is from oil vapor.

Again, where does the buildup come from then?

The fuel cleaning the port is a side effect. The fact that it is not cleaning the port does not explain where is comes from in the first place.

[Tatoon]

Does oil in the cp and ic cause a lot of chaos. I was strictly thinking of how the intake valves got totally gunked up.

[Tatoon]

Originally Posted by jwzimm

Again, where does the buildup come from then?

The fuel cleaning the port is a side effect. The fact that it is not cleaning the port does not explain where is comes from in the first place.

Oil comes from the turbos. Some of the oil ends up passing through the intake system. If I understand the process correctly....

[jwzimm]

Originally Posted by Tatoon

Oil comes from the turbos. Some of the oil ends up passing through the intake system. If I understand the process correctly....

It is true that the turbo(s) are oil lubricated and cooled, I seriously doubt that the bearings leak so much that they allow oil to become entrained in the induction tract.

[benton0311]

The oil is blown through the PCV valve and is greatly increased when the engine is under boost pressure. Boost pressure blows some of the pressurized intake charge past the piston rings, into the crank case, and when it comes out of the PCV it takes a little bit of oil with it. It's not much oil but enough to eventually start coating everything on it's way back to the intakes valves via the PCV inlet on the vacuum side of the intake.

If I'm not mistaken, the carbon on the intake valves is due to combustion products making it back on to them during periods of valve overlap when both the intake and exhaust valves are both open. This is then exacerbated by the oil that then coats the intake valves and begins to turn to sludge when it cokes due to the heat.

[ferocity02]

Oil enters the intake tract through the PCV system which vents crankcase oil vapors and moisture into the intake tube pre-rear turbo. Adding an oil catch can is supposed to help this (mine didn't).

Each intake port in the cylinder head also has a small hole that lets oil vapor get sucked straight into the engine. A catch can does not help this. But you can block off these ports although it's a little involved and I'm not sure how much it actually helps.

[Jeff@TopGearSolutions]

Originally Posted by jwzimm

Again, where does the buildup come from then?

The fuel cleaning the port is a side effect. The fact that it is not cleaning the port does not explain where is comes from in the first place.

It comes from the internal combustion process which is the same place it would normally be coming from on a port fuel injection car, except the port fuel injection car has fuel to clean the valves. As mentioned before, only a small portion comes from the PCV side and oil vapors.

Regardless of an OCC, people will still have to clean their valves probably every 25,000 miles. I used to say 35,000 but it appears even sooner provides further benefit.

Originally Posted by benton0311

If I'm not mistaken, the carbon on the intake valves is due to combustion products making it back on to them during periods of valve overlap when both the intake and exhaust valves are both open. This is then exacerbated by the oil that then coats the intake valves and begins to turn to sludge when it cokes due to the heat.

Exactly

[jwzimm]

Originally Posted by Jeff@TopGearSolutions

It comes from the internal combustion process which is the same place it would normally be coming from on a port fuel injection car, except the port fuel injection car has fuel to clean the valves. As mentioned before, only a small portion comes from the PCV side and oil vapors.

Regardless of an OCC, people will still have to clean their valves probably every 25,000 miles. I used to say 35,000 but it appears even sooner provides further benefit.



Exactly

So then please explain why the N55 does not experience nearly the kind of build up that the N54 does? Both of them use the exact same injection method (and, indeed, the same injectors).

Here is an example from my own engine at 45k miles: http://www.e90post.com/forums/showth...ghlight=walnut

[benton0311]

Are you referring to oil sludge or carbon buildup? They're two different things from two different sources. If you look closely at the pics in your link you can see that while there is minimal oil sludge buildup, there is still carbon on your valves.

The reduced oil sludge buildup could be attributed to a number possible factors, including:

* Different driving styles spending less time under boost.
* Less time under boost due to reduced part throttle boost from the slower spooling, single turbo
* Revised PCV design for one or both valves
* Revised PCV routing causing a change in efficiency
* Different intake plumbing resulting in oil vapor being deposited elsewhere along the intake tract
* Tighter piston/piston ring to cylinder wall clearances at operating temperature allowing for reduced blow-by

As for the carbon buildup, it's there in the photos and I can't say if the carbon is any better or worse than an N54 at that mileage. If there is a difference in carbon buildup between the two engines it would most likely be due to changes in VANOS programming allowing for more or less overlap, which would affect how long the intake valves are exposed to the exhaust gases.

Valve overlap is used to increase the intake port velocity at a certain RPM for performance. However, in some engines variable valve timing (VANOS) has been used to open the intake valves at different times to help recycle exhaust gasses in lieu of an EGR valve. I don't know if the N55 has an EGR or not, the N54 does not.

[jwzimm]

The issue with the build up is the blocking of the port. As you can see in my photos, the ports were completely open. The dusting of carbon had no measurable depth. Comparing this to the multitude of N54's that have had theirs cleaned it is clear that whatever changes were made to the N55, they have been effective at reducing this buildup.

The carbon from the exhaust gasses is not what causes the heavy and greasy buildup that leads to constriction of the ports. If that were the case wouldn't the exhaust ports and the turbine be caked over and blocked well before the intake ports?

The bad blocking deposits is a result of oil in the induction system. I have seen nothing that suggests otherwise.

[stanlalee]

Originally Posted by jwzimm

So then please explain why the N55 does not experience nearly the kind of build up that the N54 does? Both of them use the exact same injection method (and, indeed, the same injectors).

Here is an example from my own engine at 45k miles: http://www.e90post.com/forums/showth...ghlight=walnut

Every direct injection engine on the planet that does not also have port injection in tandem with direct injection gets carbon build up on the intake valves. Doesn't matter if it's the N54, N55, direct injected GM V6, AUDI/VW you name it. The N55 might not cake up as quickly as I'm sure most manufacturers have learned SOMETHING with their first generation direct injection engines but the solution is port injection in tandem to wash the valves. Toyota was the first working on such a production fuel system but with the added expense I'm sure tricks with the PVC and oiling have been implemented to prolong the inevitable vs running quasi port and direct injection.

[benton0311]

Originally Posted by stanlalee

Every direct injection engine on the planet that does not also have port injection in tandem with direct injection gets carbon build up on the intake valves. Doesn't matter if it's the N54, N55, direct injected GM V6, AUDI/VW you name it. The N55 might not cake up as quickly as I'm sure most manufacturers have learned SOMETHING with their first generation direct injection engines but the solution is port injection in tandem to wash the valves. Toyota was the first working on such a production fuel system but with the added expense I'm sure tricks with the PVC and oiling have been implemented to prolong the inevitable vs running quasi port and direct injection.

Toyota's solution for the BRZ/FRS was the first thing that came to mind when talking about DI vs PI injection and deposits on the intake ports and valves. Subaru did the bulk of the engine design but Toyota's contribution was the dual injection setup and ECU.

The Mazdaspeed 3, one of the earlier (if not earliest) DI turbo cars available in the U.S. is also known for intake port buildup.

If the reduction in oil deposits and/or carbon on the N55 vs. N54 is universally true, then it would appear that BMW made revisions to the PCV design and/or intake cam timing to reduce what they saw as a long term maintenance issue with the N54. I haven't checked the external PCV part numbers but also keep in mind there's also the PCV inside the valve cover, at least on the N54 and I have found anecdotal reports that the PCV is a different design.

As for the OP, I've been running the BMS catch can for about 40,000 miles and have found that it's about 1/2 full (up to the baffles) every 2nd or 3rd oil change. I can't say how much this impacts oil deposits along the intake tract and ports but it is definitely trapping oil. If you're not looking to spend much on a catch can, I wouldn't cheap out on the ebay cans as you would be taking a shot in the dark, at best. Improperly designed and manufactured cans are known to not work very well, not only on BMWs but on other vehicles as well. They might work if you had a vehicle with worn piston rings and a really bad PCV system that was literally dumping oil out of the PCV. The design of the can, baffles, and plumbing to the can affects how well it it accepts air flow and separates oil vapor into liquid oil inside of the can before returning the air to the intake.

[Mike@N54Tuning.com]

Originally Posted by benton0311

As for the OP, I've been running the BMS catch can for about 40,000 miles and have found that it's about 1/2 full (up to the baffles) every 2nd or 3rd oil change. I can't say how much this impacts oil deposits along the intake tract and ports but it is definitely trapping oil. If you're not looking to spend much on a catch can, I wouldn't cheap out on the ebay cans as you would be taking a shot in the dark, at best. Improperly designed and manufactured cans are known to not work very well, not only on BMWs but on other vehicles as well. They might work if you had a vehicle with worn piston rings and a really bad PCV system that was literally dumping oil out of the PCV. The design of the can, baffles, and plumbing to the can affects how well it it accepts air flow and separates oil vapor into liquid oil inside of the can before returning the air to the intake.

Well said.. I think for the price an OCC is a no brainer to help prevent the build up. I always recommend them especially when changing out your FMIC. Its shocking to sometimes see 1/4 cup of oil pour out of the FMIC.

Mike

[benton0311]

Originally Posted by Mike@N54Tuning.com

Well said.. I think for the price an OCC is a no brainer to help prevent the build up. I always recommend them especially when changing out your FMIC. Its shocking to sometimes see 1/4 cup of oil pour out of the FMIC.

Mike

I refer to the intercooler as BMW's factory oil catch can for the 335i. I actually think they should make that the nomenclature for the OEM interooler in parts catalogs.

[Jeff@TopGearSolutions]

Originally Posted by jwzimm

So then please explain why the N55 does not experience nearly the kind of build up that the N54 does? Both of them use the exact same injection method (and, indeed, the same injectors).

Here is an example from my own engine at 45k miles: http://www.e90post.com/forums/showth...ghlight=walnut

I wouldn't be able to comment with a 100% certainty on how BMW designed their engine or how it differed from N54.

However, what is still true is that all direct injection engines have more build up on the intake valves then would a port fuel injection motor.

There is inconsistency across DI engines and how much they build up. Some worse then others and some less then others even of the same platform.

Driving habits and other exterior conditions that are still being learned today affect build up.

Even though it may appear the N55 has less then N54 engines, there is still significant build up compared to what a port fuel injection car would have.

[davidwarren]

Divers just released a massive OCC. But that's pretty much the total opposite of a cheap ebay OCC.

[stanlalee]

My only reservation about catch cans is we have winter and I've heard countless cases (none on this platform) of condensation freezing over inside the catch can and blocking the ports/flow. Not sure if this applies to all applications.