what do you think?









thank you to silent running for his help

thanks
ian

 

Good work Ian, it looks tasty. In fact I might have to move my catch tank up to there now I've got the room for it.

 

Does it have a vent??

You need to vent the fumes etc.. I cannot see one on the can?

Simon

 

no vent, from what silent running said, to do, just to put in into the pipe, the one between the inlet where the turbo is, and the crank case breather.

what way would you do it?

 

Looks nice, but how do you empty it?

I bekieve Silent running advocates still using the PCV so i presume this is just plumbed directly in the line, hence no outlet to atmosphere.

I found when i did this i collected......absolutely nothing.......it was all going back into the inlet pipe.

With the PCV valve blanked i now collect oil/water vapour. This is the way i have seen most tuners/people do it. I am well aware of the function of the PCV valve but it does not seem to cause any issues with it removed. Mine has been running 2 years like this now.

 

Ideally you want it vented if the can is sitting that close to the crank case breather. You get the most compression from that breather, if its going directly into a sealed catch can with a short run of pipe work it could cause issues with the compression backing up as there is no where for it to escape under heavy load it needs to be as free flowing as possible.

If you are running a sealed can it would be a better idea to extend the piping on the crank case breather to the can or add a filtered take of IMO

 

never seem to get any oil in mine..... but a **** load of water always collects in there,pcv blocked off like marks and cam covers to the can......

 

So have you got the crankcase and both rockers T'eed together to one pipe feeding the catch can, then return back to the inlet tract?

If so then i don't think the pipe is of sufficiant diameter to do that, also you may be catching the oil, but the vapours returning to the inlet aren't great for combustion so potentially there's more power to be had if you VTA

The cheap way of ensuring breather vapours aren't present in the inlet tract is just 3 pipes (crankcase and 2 cam covers) running down to the bottom of the engine bay, but this is frowned upon (and in competition banned) due to the potential of oil dripping onto the road / track. So the catch can is used but the vent is usually VTA.

If you've gone to the trouble of fitting the catch can its best to VTA the vapours. The crankcase pumps a lot of 'air' around at high rpm so usually this has its own seperate feed to the catch can - the 2 rockers can be T'eed together, so most catch can setups I've seen have 2 inputs and one larger outlet VTA.

It looks much better than my DIY effort - I use a rather effective tupperware container

 

I once had an XR3 with a coke bottle for an oil catch can (I didn't do it)

 

I didn't have a Coke bottle to hand at the time

 

there is a bung on the left hand side of it.

i have seen the guaid that you put on here, but im not very good with the tech terms/names of some of the bits.

have you got a pic with them on arrows etc please.

thanks
ian

 

2 hoses (1 19mm from crankcase breather and 1 15mm from rocker covers, which are tee'd together as standard) run down under car and terminated just over/behind rear axle..

PCV blanked off along with inlets into turbo intake hose, good old corks..

Cheap easy and effective, never get any drips and only water seems to be present in hoses.

As said, it's not exactly a PC way of doing it, but full decats, which produce far more pollution, seem to be OK..!

 

From personal experience of a car that kept on getting an oily inlet, turbo and intercooler, I tried every plumbing scheme going and listened to all the pub talk on here about having half a dozen pipes going here there and everywhere. I actually tried them and wasted a lot of hose and went through two or three designs of tank to see what worked and what didn't.

And in the end my conclusion was this: Subaru knew what they were doing. They designed the PCV system to draw crankcase vapours out and burn them off by the most direct and cleanest route when on part throttle - via the PCV valve in the inlet manifold. It works. They designed the rocker cover breathers to suck in clean metered air from the inlet pipe, which is exactly what they do. They work. The only thing that doesn't work well in performance terms is the pipe between crankcase breather and inlet. That blows a lot of oil vapour through the whole inlet tract when in boost conditions, therefore it is the only one which needs a catch tank. As soon as you vent this out to atmosphere you've totally lost the vacuum which keeps the crankcase clean. I really cannot see what is the point of venting to atmosphere. As long as the catch tank is relatively cold and the pipes are a decent 1/2" bore you can't go wrong.

The bottom line is that my current system of a single catch tank intercepting only the crankcase-to-inlet line runs the cleanest, catches the most oil and has kept my inlet tract bone dry under 1.4 bar boost. And that's with an aluminium cyclists bottle and a couple of 1/2" screw in hose tails plus the all important fish tank foam inside.