[Forcefed3]

Originally Posted by FlyLow335i

Surprised no one has looked into the venturi style into their exhausts.

You would still need a good OCC though. Seems kind of pointless since the turbo pretty much does the same thing.

[dzenno]

Ok, so here's my 2c on the commercially available OCCs on "this" platform and I'll post this up in the other recent OCC threads we have going This is after reading half the internet available on PCV systems outthere over the past few days lol

PCV systems are designed with vacuum in mind because that vacuum is crucial to the operation of the engine and it also impacts power delivery...crankcase pressure is something that should be considered seriously before playing with today's N54 OCCs, stress the word "seriously" here...if a restrictive OCC is introduced it can lead to both engine (valve stem seals) and turbo (seals) damage...Restrictiveness is introduced by things like the following:

1) Smaller than stock diameter tubing
2) Much much much longer than stock PCV tubing (4-5 inches stock vs 5-6 feet of tubing to/from the OCC)
3) 90deg bends at the PCV outlet
4) Baffling used inside the OCCs
5) Irregular maintenance of the OCC
6) Oil buildup in the long tubing leading in/out of the OCC over time

Some of these are addressed by today's commercially available OCCs but some are not and some just can't due to location/placement of the PCV outlet at the back of the engine.

On top of all this there's a topic of venting to atmosphere through a tiny crankcase filter. It is definitely not the way to go as the vacuum serves a crucial purpose of pulling vapours/pressure out of the crankcase. Not doing this has shown real world performance losses (thanks to Hotrod for testing this with a vbox). If you do some google-ing you'll soon realize just how critical it is to have this vacuum in your PCV system.

In summary, my opinion after researching the heck on this topic (and obviously those in the know please comment back) I've come to realize that all of today's popular and commercially available N54 OCCs and their designs are inadequate. What I'd like to have from my OCC designer is the following before putting another OCC on my car:

1) Flow rate out of the stock N54 PCV outlet under boost (positive pressure) and the amount of vacuum pulled when not under boost
2) How the above is changed by introducing their OCC and long tubing under boost and vacuum conditions

This community needs to realize that something as simple as an OCC isn't something that should be taken lightly as a lot of people, including myself, have take it to be. I had run the RR OCC for about 2.5 years now. It leaked all over the place and it didn't collect oil almost at all. It would collect maybe 2mm at the bottom of a can after about 10,000km of mixed hard/regular driving. This isn't something that I'm willing to risk instead of the stock PCV setup. I made a mistake buying the BSH OCC just 2 weeks ago and not researching this topic more thoroughly while relating it to the N54 PCV design. What drives me nuts sometimes is certain vendors totally misrepresenting OCCs to this community with pics of tons of blowby caught by them when its very clearly not the case on the N54. Yes, there's blowby, but NO there's isn't even 2% in vast majority of cases as what they're showing. The pics they show are from the VW/Audi engines that have massive amounts of blowby. I know this first hand as I've personally witnessed a BSH OCC being emptied on a 2010 VW GTI. Its ridiculous on that engine but this just isn't the case here.

I'm going stock PCV setup starting today until a more proper setup addressing the above arrives for the N54...the tiny amount of blowby from the N54 on my car is definitely more welcome than risk of damaged turbo(s) or damaged say valve guide seals..This is especially a concern with guys running high boost occasionally or those with upgraded turbos..

[sneaks]

^^^^^^Completely awesome summary. I still haven't seen proper info to bother putting in an OCC. I was considering running a vent to atmosphere, but it looks like the vacuum is required for proper operation!
Looks like the best thing to do here is use the stock setup and clean the intake valves once every couple years.

[desean81]

dzenno:

Did you look into the RSD Catch Can? It's $100 more than the others out there, I can't find much in terms of info on it other than pics.

[Joshboody]

Thanks dzenno, good summary. I have been stressing vacuum for awhile. I don't have any concerns with the bsh in this respect... it's the filtering that i have concerns with. I do think any n54 upgrade is probably not much better than stock at this time. 50% compared to 100% saturation of the intake piping will still require a good cleaning in the future.

For a good OCC, it needs to have a removable, cleanable or changable filter. One that flows proper volume should not be difficult. It's the routing that adds some difficult in long lines, elbows, etc as dzenno mentioned... this requires some testing.

I think there is one n54 option with removable filter... but not sure.

[dzenno]

RSD OCC has the same limitations as discussed above, namely 6 feet of tubing vs 4-5 inches stock, 90deg elbow at PCV outlet, not sure but could be others as well

[bahn stormer]

Dzenno, I appreciate the time you put into your research but I am a little skeptical.

Maybe the BSH does not catch as much oil as it could but I have never heard a suggestion that it could be causing damage due to being overly restrictive. On the contrary, I thought it didn't collect as much oil as other OCCs due to the more free flow design (larger diameter hoses/ports and less restrictive collector plate).

I have viewed the BSH OCC as simply collecting a little more oil than I would have otherwise with the stock PCV system. Do you have any evidence or know of any testing that show it to be any worse than the stock PCV system?

The N54 will also by design pass less oil back to the intake pipe as compared to other platforms due to the vortex separators built into the head.

[dzenno]

Originally Posted by bahn stormer

Dzenno, I appreciate the time you put into your research but I am a little skeptical.

Maybe the BSH does not catch as much oil as it could but I have never heard a suggestion that it could be causing damage due to being overly restrictive. On the contrary, I thought it didn't collect as much oil as other OCCs due to the more free flow design (larger diameter hoses/ports and less restrictive collector plate).

I have viewed the BSH OCC as simply collecting a little more oil than I would have otherwise with the stock PCV system. Do you have any evidence or know of any testing that show it to be any worse than the stock PCV system?

The N54 will also by design pass less oil back to the intake pipe as compared to other platforms due to the vortex separators built into the head.

My comments aren't centered around a BSH or AR or RSD or any particular company. It is around the design of all of them which is literally imposed on them due to space constraints around the N54 engine. I obviously don't have direct proof but its really not required here for what I'm bringing up. We all know sharp bends are restrictive and in most cases we have 90deg bends here. What happens to vacuum which is relatively small if you extend the tubing from 5inches to 5 feet? What happens to flow when you place a restriction in its path? We can only question these at this point and its really up to the vendors/designers of these cans to prove us wrong which I'd happily accept provided proper research/results. Keep in mind I've had an RR OCC, just 2 weeks ago I got the BSH OCC and only did real research on this topic after only to find issues never discussed in depth and things that completely look wrong in the design of them. Marketing of some of these OCCs is also complete false advertising when it comes to these engines and its been happening ever since they were introduced to this community.

In the end, all I'm looking for is for the OCC designers/vendors to bring some facts to the table on their catch cans and prove that they provide "proper" crankcase pressure ventilation under high boost conditions AND that they remove some blowby from the engine. What happens with all these designs as boost pressures go up? What about higher air volumes with upgraded turbos? These are all non-issues for stock boost guys most likely, so lets get that out of the way

So far, we've only seen blowby in certain cases (a little I should say). At the same time, we've seen some turbos go with the OCCs installed and hotrod has proven that venting to atmosphere causes loss of power (lower traps using vbox testing) so crankcase ventilation is crucial.

[bahn stormer]

Originally Posted by dzenno

My comments aren't centered around a BSH or AR or RSD or any particular company. It is around the design of all of them which is literally imposed on them due to space constraints around the N54 engine. I obviously don't have direct proof but its really not required here for what I'm bringing up. We all know sharp bends are restrictive and in most cases we have 90deg bends here. What happens to vacuum which is relatively small if you extend the tubing from 5inches to 5 feet? What happens to flow when you place a restriction in its path? We can only question these at this point and its really up to the vendors/designers of these cans to prove us wrong which I'd happily accept provided proper research/results. Keep in mind I've had an RR OCC, just 2 weeks ago I got the BSH OCC and only did real research on this topic after only to find issues never discussed in depth and things that completely look wrong in the design of them. Marketing of some of these OCCs is also complete false advertising when it comes to these engines and its been happening ever since they were introduced to this community.

In the end, all I'm looking for is for the OCC designers/vendors to bring some facts to the table on their catch cans and prove that they provide "proper" crankcase pressure ventilation under high boost conditions AND that they remove some blowby from the engine. What happens with all these designs as boost pressures go up? What about higher air volumes with upgraded turbos? These are all non-issues for stock boost guys most likely, so lets get that out of the way

So far, we've only seen blowby in certain cases (a little I should say). At the same time, we've seen some turbos go with the OCCs installed and hotrod has proven that venting to atmosphere causes loss of power (lower traps using vbox testing) so crankcase ventilation is crucial.

You have some good points but I would prefer not to react to these opinions without more concrete evidence/testing, at least for the time being.

Longer hoses/bend will reduce the vacuum drawn at the vortex separators and subsequently the flow but I am not sure by how much and it may be negligable. I could really argue either way at this point. Maybe someone could tap in a vacuum gage on the pipe and check both stock PCV and with OCC at idle and at full boost. Has anyone done a V-box test stock PCV vs. OCC?

[dzenno]

Originally Posted by bahn stormer

You have some good points but I would prefer not to react to these opinions without more concrete evidence/testing, at least for the time being.

Longer hoses/bend will reduce the vacuum drawn at the vortex separators and subsequently the flow but I am not sure by how much and it may be negligable. I could really argue either way at this point. Maybe someone could tap in a vacuum gage on the pipe and check both stock PCV and with OCC at idle and at full boost. Has anyone done a V-box test stock PCV vs. OCC?

No one has done stock PCV vs OCC testing yet. Hotrod has done stock PCV vs venting to atmosphere and noticed a measurable loss in trap speed (power)...

I know what you're saying about early conclusions and I completely agree. This is a similar situation we were in when lightweight crankshaft pulleys were first introduced to the community. People started buying them while others were firmly against them as they didn't have a harmonic balancer inside and were just light, just search for NST on this forum and n54tech. I even bought one only to sell it right after realizing how important a harmonic damper really was on this particular engine. About a year later now, certain people that ran those have reported crankshaft issues in the form of bearing failures that only point at the pulley and nothing else. Back then certain people were defending the use of that type of pulley by making remarks of how the N54 was internally balanced and didn't really need an external harmonic balancer. And yet BMW went through the hassle of making one many times more expensive to manufacture and provide stock on this car.

Point is that I just plain refuse to run anything on this car anymore that hasn't had proper research results revealed to the community as to the before/after effects (ok, well, yes, there are definitely exceptions). Showing pics of blowby caught on a vw/audi is not the way to market this type of product when in reality, in higher boost applications especially, it has a huge potential for screw up

[sneaks]

Originally Posted by dzenno

Point is that I just plain refuse to run anything on this car anymore that hasn't had proper research results revealed to the community as to the before/after effects (ok, well, yes, there are definitely exceptions). Showing pics of blowby caught on a vw/audi is not the way to market this type of product when in reality, in higher boost applications especially, it has a huge potential for screw up

Afe throttle body spacer?

[dzenno]

Originally Posted by sneaks

Afe throttle body spacer?

Next to the lightweight crankshaft pulley BS that one takes a strong 2nd place lol man the BS we're served sometimes..