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View Full Version : Rb25det oil catch can / venting quesiton

EnemyS15
11-23-2012, 07:54 PM
I have a S2 rb25

Valve cover has 2x welded -8 an male ends and the pcv welded shut (purchased off of another Zilvian)

Oil catch can is a greddy, similar to the pic http://www.autocarparts.com/images/GReddy/oilcatch_can.jpg


I am wondering if it would be possible to replace the drain plug on the bottom of the catch can with an -An fitting/line, run the line to an -AN "Y" fitting connecting the oil drain from top mount turbo to block, and the oil catch to the block as well (creating a constant circulation of whatever blow by oil is collected). Would this set up form a sufficient vent for crank case pressure?

Pic of a Y I would use (not exact size) http://www.jegs.com/images/photos/500/555/555-15165.jpg

If this is not a good idea, any other ideas would be appreciated. Just remember PCV is welded shut on the cover.
fliprayzin240sx
11-24-2012, 07:36 AM
Why would you want the sludge back into your engine? The whole point of a catch can is to keep that same oil out of the engine since its usually contaminated with gas.
bullfrogg0
11-24-2012, 07:40 AM
I know that's how sr20's are set up from the factory....
EnemyS15
11-24-2012, 09:25 AM
Why would you want the sludge back into your engine? The whole point of a catch can is to keep that same oil out of the engine since its usually contaminated with gas.

Just throwing out an idea before I just go back to running a line to the intake.
EnemyS15
11-24-2012, 11:26 AM
Ok forget the draining part. Would routing the line to the y be sufficient source to relieve crank case pressure?
fliprayzin240sx
11-25-2012, 12:38 PM
Did you look thru this? I'm still learning about the Rb so I'm not sure 100% how the crankcase is relieved. SRs has a line that goes from the crankcase to the valve cover to relieve the pressure. Not sure if the Rb has the same setup.

RB20 RB25 Catch Can PCV Breather Guide (http://www.nicoclub.com/archives/rb-catch-can-pcv-breather-guide.html)
PrimeDirective
11-25-2012, 01:17 PM
With the pcv plugged use the Y to connect the two top valve cover ports to one line and attach it to the catch can. Then from the other port in the catch can connect it to a vacuum only source, that never sees boost, so either your exhaust or your intake pipe after the Maf and before the turbo.

This will release the pressure but also put a vacuum on the crack case to help seal your rings.