Thomasfd

Hi guys i know this topic is being discused in many threads but everyone says a different way of installing one and I got really confused.
I have a Greddy oil catch can and I have the top nipple of the filler neck to one of the nipples on the catch can and the other one from the oil catch can to the intake with a pcv valve i also capped the lower nipple on the filler neck, is this the correct way? I also have the center iron open to air. Would appreciate a straight forward answer because im really confused here.

suzukisteve

iTrader: (4)

This is incorrect, unless your catch can has a check valve. You PCV valve has a check valve to allow vacuum to be pulled from you crank case, but not allow boost to enter your crank case. The PCV system is not needed. My '95 did not come with one from the factory. The nipple on the UIM for it was blocked off. Unless your catch system has a check valve in it you run the risk of over pressuring you crank case which is bad to go. Just remove your PCV and block off the nipples.

From there, here are your options depending on if your catch can has a breather filter.

If it does not have a breather filter, run a line from the oil fill neck to a nipple on your intake. It can either be the one at the base of the primary turbo itself or the original line that was connected to the oil fill neck.

If it does have a breather filter, you may:
1) Run a line from the oil fill neck to the catch can and then another line from the catch can to the intake.
2) Run a line from the oil fill neck to the catch can and block off the nipple on the intake.

Thomasfd

Its a single turbo so i do not have the inlet on the turbo.

Thomasfd

Also my catch tank has two nipples with no breather

Ziggy

iTrader: (1)

What you currently have technically works, but less than ideal. I prefer to not have the PCV, less things to fail and it won't collect anything while under vacuum as the pathway will be shut by PCV to prevent vac leak. You also may not have sufficient venting only going through PCV. Early FD's had both PCV and 2nd line into intake elbow. later models had no PCV but 1 vent into elbow. PCV valve is a pretty major restriction, where the line right to the elbow has no additional restriction other than hos size. This is all @ stock boost I'm assuming as single you are running higher than 10psi which will have more pressure and blow by into oil pan. I agree with Steve, try at all possible to ditch the PCV valve.

Primary purpose of system is to vent pressure from oil pan as much as possible. Secondary purpose is to catch as much blowby junk as possible (don't reverse these purposes). Catch can won't catch everything and some of the junk will still exit move past the catch tank and into whatever way you choose to rig up the exit of the catch can.

For the output it just needs to be vented somehow so that crankcase pressure can escape, MOST critically while under boost but I would like it to passively collect as much blow by as possible and there is still some while under vacuum. Many ways it can be connected up to do this. You have to figure out where that stuff is going to end up going from the exit of the catch can. A few ways I can think of with only have 1in and 1out on can and currently no way to connect to intake side of turbo.

1) You can still install a breather filter on the out barb (if there's space). Filter will soak up most of anything that might make it through the can.
2) If there isn't space, you can run the hose to a remote filter. Might need a step up fitting to make the smaller exit hose connect to larger filter.
3) Run hose under the car and have it vent underneath open into atmosphere. I don't recommend this just because it's going to dump anything the catch doesn't collect from the crankcase onto the road
4) Drill and glue a fitting onto air filter and connect output hose. Any extra fumes will still be put into and burned by system.
5) Weld fitting onto any bit of metal intake tube you might have going into turbo and connect output hose. Any extra fumes will be put into and burned by system.
6) Drill hole in top of catch can and install an air compressor fitting that would fit a vent filter. Would need a nut couple washers and something to seal the air fitting to the hole that was drilled in can.
7) Final, run one nipple through PCV valve into UIM like stock, and then use the other nipple to route through catch can. This preserve 2 venting lines so ensure adequate venting, and catch can will still catch some additional stuff, but you will catch less stuff this way and some is completely bypassing can and going through PCV valve instead. It does prevent you from having to plug holes etc. but this is really the worst of both worlds, just giving you all the options I can think of.

I also have a question on the center iron, I believe all -REW's have that vent hole welded shut from factory a bit confused on what engine you have. and if it is open you would be getting tons of dust going through there into your oil and could start spewing oil out of it under hard right turns?

DaleClark

iTrader: (55)

I've posted many times about the Jaz catch can - a small can with 2 nipples and a filter on top. Mine has been working great for ages. Search on that topic.

For most non-hardcore track cars that setup is all you need.

Dale

Ziggy

iTrader: (1)

Also while on topic, I'm very against the micron filters that I see in some cans. Right from the start they don't allow much venting as fumes and air have to push through this restrictive filter element and they can get clogged very quickly and potentially completely lock up the venting system. Violates the primary purpose of the system of ensuring adequate venting first.

Thomasfd

Thanks ziggy for the help really straight forward. I think im going with the first choice to add a breather filter on the catch can. Ill disconect the pcv hose and just add the breather filter, leaving the other one going to the oil filler nipple?