Breathing System Plumbing

[leeroy_25]

Okay. I am specifically working on an RB30/RB26 combo but I guess the question applies across the board hence I have posted it here.

I have currently got my breather setup similar to a factory setup. I am converted to a large single turbo and have the exhaust cam cover breathing to the turbo inlet and the inlet cam cover venting behind the throttle bodies as standard. In addition I have a breather/drain connected from the back of the head to the sump high up as possible. I want to do away with this set-up under recommendation from a few people and run a simple catch tank setup.. The car is road used not a track car if this helps.

My plan was to run the cam cover breathers to the top of a catch bottle and then I would have liked to run 2 from the sump to the bottle. One high as a breather and one low as a drain. But as I only have the option to run one from the sump I was thinking about putting a t piece into the pipe running between the head and sump as close to the sump as possible and running this to the bottom of the bottle so if there is oil coming in to the bottle it can drain out and any major pressure could blow back up it?

Please let me know your thoughts on this set-up. The catch tank would of course be vented with a filter.

Thank you

Lee

[Dale FZ1]

If you want to run a drain-back to sump from the catch can, be aware that crankcase pressure can work against your intended outcomes. Try installing a one-way valve (eg a PCV) in the drain-back hose. That would stop the crank from venting into the catch-can, but allow the contents of the can to run back when the crankcase is not trying to displace heaps of air either through piston movement or blowby.

It may be worthwhile also looking at improving the screens hiding under the baffle plates in your cam covers, just give the oil some chance to drop out of suspension before the air is pushed into your catch can.

Each engine will breathe differently according to build and application. ie some people will have to go to greater lengths to resolve issues. There are a few threads about that can help, with diagrams and/or pictures. Worth a search IMO.

[tricstar]

what about just a simple catch/can- breather tank setup, do you really need a drain back/vent to the sump ? are you getting that much blowby on a street driven car ?

[bubba]

You could run the line from the sump to a T-piece with a ball valve, one line high on the catch can and one on the bottom for a drain but have it as a manual drain, i.e. normally the drain is shut and the line from the sump vents to the catch can. If you find it's filling up then you can open the ball valve and drain back to the sump.

[3BEPKA]

+1 for simple set up,don't need for drain in my opinion and PCV .... just block it off ( get plug machined or something)

Edit:

Hope it helps

Edited June 8, 2011 by 3BEPKA

[leeroy_25]

Thank you so much for the replies guy's there are so man opinions on this it is hard to know which way to go. I am all for simple as long as it's effective.. All sorts of fancy setups have been suggested with vents to the downpipe to draw fumes etc.. All very nice but I was thinking overkill for my street car.

Now I like your setup 3BEPKA. Do you not have a vent or connection to the bottom end at all? It looks very much like a RIPs setup?

I have to say I thought the pressure in the sump would be the main cause of breathing issues as like Dale says I guess this is working against the oil trying to drain back from the head to the sump normally? So having a vent for the sump should be a good mod? I guess the argument is it is not there on the standard setup!?

I like the idea of having a t-piece into my head-sump line that goes to the top of the breather as well so I can get the sump breathing through this but oil can still try and drain from the head back this was if needed. I guess if it did turn out to breath a lot (hopefully note!) I could then add another t-joint to allow the catch tank to be drained back to the sump via a valve.. but this is starting to get a bit messy in pipework!

just to be clear I don't think I have a breathing issue.. I had a small bit of oil blow/get sucked out once after a hard run.. Then someone looked at the breather setup I had and said I should really have it setup to a catch bottle anyway!

So the PCV that needs blocking off I assume is the one that goes in behind the throttle plates. At a guess the fitting in there unscrews and you can blank it with an M10 bolt? or whatever thread size it is?

Dale you also mention improving the screens in the cam covers? please explain more. I am not sure what you mean by this or how to do so? The baffles in the top of the cam covers have some kind of foam filter behind them from memory.

Lastly the connections for the breather pipes in the top of an r26 cam cover.. can these be turned around or removed easily? I either would like it so the spouts to connect the covers together face each other leaving the other spouts facing forward towards my catch tank or remove them completely and replace with some nice 90deg fittings.

Thank you

Lee

[3BEPKA]

Thank you so much for the replies guy's there are so man opinions on this it is hard to know which way to go. I am all for simple as long as it's effective.. All sorts of fancy setups have been suggested with vents to the downpipe to draw fumes etc.. All very nice but I was thinking overkill for my street car.

Now I like your setup 3BEPKA. Do you not have a vent or connection to the bottom end at all? It looks very much like a RIPs setup?

I have to say I thought the pressure in the sump would be the main cause of breathing issues as like Dale says I guess this is working against the oil trying to drain back from the head to the sump normally? So having a vent for the sump should be a good mod? I guess the argument is it is not there on the standard setup!?

I like the idea of having a t-piece into my head-sump line that goes to the top of the breather as well so I can get the sump breathing through this but oil can still try and drain from the head back this was if needed. I guess if it did turn out to breath a lot (hopefully note!) I could then add another t-joint to allow the catch tank to be drained back to the sump via a valve.. but this is starting to get a bit messy in pipework!

just to be clear I don't think I have a breathing issue.. I had a small bit of oil blow/get sucked out once after a hard run.. Then someone looked at the breather setup I had and said I should really have it setup to a catch bottle anyway!

So the PCV that needs blocking off I assume is the one that goes in behind the throttle plates. At a guess the fitting in there unscrews and you can blank it with an M10 bolt? or whatever thread size it is?

Dale you also mention improving the screens in the cam covers? please explain more. I am not sure what you mean by this or how to do so? The baffles in the top of the cam covers have some kind of foam filter behind them from memory.

Lastly the connections for the breather pipes in the top of an r26 cam cover.. can these be turned around or removed easily? I either would like it so the spouts to connect the covers together face each other leaving the other spouts facing forward towards my catch tank or remove them completely and replace with some nice 90deg fittings.

Thank you

Lee

Only vent I have is filter on the side of can but there is no connection to bottom end. Regarding PCV, once you take the hose out from the side of cam covers there is just a hole,no thread. As you can see in photo from previous post i used brass fitting (that was machined to size) and punched in.

[leeroy_25]

Arhh.. I can only just see it I think in that picture. You mean the hole on the fitting in the cam cover needs blanking? I have RB26 covers so slightly different. I can connect the two covers together and no need to blank anything but I would need to blank of the fitting on top of the throttle body back plate where the RB26 inlet cover connects to.

On a side note anyone know how to contact admin? I don't seem to be getting notification e-mails any more.. I only checked in by chance the last couple of times!?

Cheers

Lee

[tricstar]

heres my 26 with the breather coming off the other side, to the small bottle in front of the pod, never get any blowby

[leeroy_25]

Well that's nice and easy! I could just go with that and be one with it.. Although I think I will take both breather to a bottle and leave it at that. Just got to try and turn the fittings in the cam cover around to suit. And out what thread I need to block the PCV.

Cheers

Lee