[Transport3r]

After reading shiv's post about a poorly designed OCC messing up the A/F ratios of one of the upgraded turbo cars, I kept thinking about what has bothered me for a while about the catch cans available for our motor.

I've read form a few sources that the N54 has a relatively large amount of PCV flow. No source has actually been able to provide me with actual numbers. This led me to wondering whether any of the current catch cans have undergone flow testing during development, or if everyone just welded some brackets to a can/filter, and shipped that out with some hoses. It seems like every manufacturer has a choke point in their OCC solution: AR and RR have relatively thin tubing, and the BSH unit uses that brass elbow which is pretty small.

I'm surprised nobody is actually just putting a breather filter on the crankcase hose and capping off the intake hole. Much less work/money and no chance about choking the PCV flow. Would a breather filter even be necessary or does the N54 have a check valve on the PCV system?


link to Shiv's thread:
http://www.e90post.com/forums/showthread.php?t=495848

[Forcefed3]

OCC's are not really talked about that much. I have one, but I dont know as much as I should about it.

[jkrig]

Originally Posted by joshuo

After reading shiv's post about a poorly designed OCC messing up the A/F ratios of one of the upgraded turbo cars, I kept thinking about what has bothered me for a while about the catch cans available for our motor.

I've read form a few sources that the N54 has a relatively large amount of PCV flow. No source has actually been able to provide me with actual numbers. This led me to wondering whether any of the current catch cans have undergone flow testing during development, or if everyone just welded some brackets to a can/filter, and shipped that out with some hoses. It seems like every manufacturer has a choke point in their OCC solution: AR and RR have relatively thin tubing, and the BSH unit uses that brass elbow which is pretty small.

I'm surprised nobody is actually just putting a breather filter on the crankcase hose and capping off the intake hole. Much less work/money and no chance about choking the PCV flow. Would a breather filter even be necessary or does the N54 have a check valve on the PCV system?

Not as schooled on the N54 either but I have wondered the same, that how it was done in my honda tinkering days.......vent to atmosphere

[themyst]

Originally Posted by joshuo

After reading shiv's post about a poorly designed OCC messing up the A/F ratios of one of the upgraded turbo cars, I kept thinking about what has bothered me for a while about the catch cans available for our motor.

I've read form a few sources that the N54 has a relatively large amount of PCV flow. No source has actually been able to provide me with actual numbers. This led me to wondering whether any of the current catch cans have undergone flow testing during development, or if everyone just welded some brackets to a can/filter, and shipped that out with some hoses. It seems like every manufacturer has a choke point in their OCC solution: AR and RR have relatively thin tubing, and the BSH unit uses that brass elbow which is pretty small.

I'm surprised nobody is actually just putting a breather filter on the crankcase hose and capping off the intake hole. Much less work/money and no chance about choking the PCV flow. Would a breather filter even be necessary or does the N54 have a check valve on the PCV system?


link to Shiv's thread:
http://www.e90post.com/forums/showthread.php?t=495848

Terry@BMS was selling crankcase filters for $25 a pop. The problem with them is, they smell like shit as I stated previously. If you can deal with that smell, perhaps it's a good solution.

I have a BSH OCC, and I didn't notice any detrimental effects on performance one way or another. There's no oil in the can either, but it's only been on there for about 1000 miles

[STONEY_M5]

Originally Posted by jkrig

Not as schooled on the N54 either but I have wondered the same, that how it was done in my honda tinkering days.......vent to atmosphere

same here

[Joshboody]

Originally Posted by themyst

Terry@BMS was selling crankcase filters for $25 a pop. The problem with them is, they smell like shit as I stated previously. If you can deal with that smell, perhaps it's a good solution.

I have a BSH OCC, and I didn't notice any detrimental effects on performance one way or another. There's no oil in the can either, but it's only been on there for about 1000 miles

I wonder if a breather is a good idea. connected to the intake track there is a vacuum and it may help pull the fumes. This isn't just a hole in the valve cover, but a somewhat elaborate cone thingy that has some restriction. Don't know.

I also have BSH and everything seems fine. Small amount of oil after 10K miles, but some cyclones probably better than others.

[Chowbow]

Originally Posted by jkrig

Not as schooled on the N54 either but I have wondered the same, that how it was done in my honda tinkering days.......vent to atmosphere

Originally Posted by themyst

Terry@BMS was selling crankcase filters for $25 a pop. The problem with them is, they smell like shit as I stated previously. If you can deal with that smell, perhaps it's a good solution.

I have a BSH OCC, and I didn't notice any detrimental effects on performance one way or another. There's no oil in the can either, but it's only been on there for about 1000 miles

I was wondering why there aren't many N54s that just vent as well. If it smells like crap, you can also just use a hose to put the breather farther away so it doesn't get pulled into the cabin, no?

[Big Tom]

Here's my DIY OCC (Which cost me a total of $34):






It's quite similar to the AR Design $229 OCC :

[possible335i2008]

Parts list please!!!

[dzenno]

Originally Posted by possible335i2008

Parts list please!!!

+1

What's the diameter of the oil canister? Any filter inside?

[H4n]

Originally Posted by possible335i2008

Parts list please!!!

1 !

[M3 Eater]

Don't do it TOM!... Big Tom's DIY manuel for the N54... $29.99. Also available on DVD DIY video. JK... $39.99

[Transport3r]

Originally Posted by Big Tom;9061264

[URL=http://img600.imageshack.us/i/cimg4834.jpg/

[/URL]

How's the smell?

[R1000K3]

Nice work BigTom

[Big Tom]

Originally Posted by dzenno

+1

What's the diameter of the oil canister? Any filter inside?

The diameter of the oil canister is ~41 mm.

It was a bronze filter inside, but I removed it for maximum flow through the OCC:






Here's some pics of the installation:









And here's a bonus pic (this badge will probably give me at least 25-30 whp more ):

[dzenno]

Tom, what filter did you use? I'm having a hard time finding that small a filter up here in Canada..

When I asked about the diameter of the oil canister I actually wanted to know the inner diameter of the inlet on it...

[Big Tom]

Originally Posted by dzenno

Tom, what filter did you use? I'm having a hard time finding that small a filter up here in Canada..

When I asked about the diameter of the oil canister I actually wanted to know the inner diameter of the inlet on it...

The diameter on the in and outlets on the OCC are 11/16" (17 mm) and I'm using a ½"-hose on the inlet and a ½"-filter on the outlet.
I bought it from here: http://www.jula.se/vatten-smutsavsklijare-123936
...and I've painted it black for a more stealthy look in the engine bay.

*EDIT* The diameter on the in and outlets on the OCC are 11/16" (17 mm) and NOT only 3/8" as I wrote earlier!

[dzenno]

If I'd done it I would've preserved the 3/4" same as the diameter of the PCV outlet..you really shouldn't make it smaller IMO..

[ultimateracing335]

Its 2 small. Reatain the 3/4 diameter.

[Transport3r]

Does anyone know what the piping size is on the BSH can? Searched but couldn't find..

[Big Tom]

Originally Posted by ultimateracing335

Its 2 small. Reatain the 3/4 diameter.

AR Design is also using ½" hoses for their OCC...

[Imperator]

Originally Posted by joshuo

Does anyone know what the piping size is on the BSH can? Searched but couldn't find..

I just installed mine today-- it looks like 5/8" but I haven't measured it yet. I'm not happy with the cuts I made in the provided hose so I'm going to try to find some silicone heater hose as an equivalent to re-do the routes. While I'm at it, I'm also thinking of eliminating that plastic PVC box altogether but haven't looked at it to see if there's a check valve inside.

I'm hoping to eliminate the metal elbow piece and route straight to the valve cover... there must be some reason that plastic box was retained.