sketron1 Posted May 17, 2016 Share Posted May 17, 2016 Posted this on my engine refresh thread but am not getting any response. I'm doing away with the stock PCV and going all hoses, PCV valve, simplified. Here's my proposed PCV setup. I should mention I did remove the two metal pipes which are joined and run under the intake manifold (one for coolant, one for PCV) and will use flexible hose instead. Also simplifying the evap system, straight from tank to inlet. http://uploads.tapatalk-cdn.com/20160516/f9d1ff7207ce5a38a9986803b84fc264.jpg Anyone see any issues with the proposed setup? It should function identical to stock. Link to comment Share on other sites More sharing options...
cBax Posted May 21, 2016 Share Posted May 21, 2016 Im not sure you understand how it all works. What is the TEE doing? Looks like you are just connecting your valve cover vents to the crank case. No reason to have both valve covers independently connected to the inlet either, just do a tee. Where is the PCV valve venting to? The connection you have shown is a vacuum source that just opens the valve. But where is the vent going? I wouldn't tie the tank vent straight to the inlet either. The solenoid opens/closes under certain instances and without it you will have a post-MAF vacuum leak 24/7. '05 Outback XT www.facebook.com/baxleysspeedshop www.baxleysspeedshop.com Link to comment Share on other sites More sharing options...
sketron1 Posted May 21, 2016 Author Share Posted May 21, 2016 The tee just connects valve cover vents (the bigger pair, not the smaller pair adjacent to these) to the crankcase. This is same as factory setup. I have the smaller valve covers independently connected to the turbo inlet as it will use less hose, and the inlet has the extra bung or two (no other reason). I've been reading debates about how jdm emissions are setup. My understanding was the tank evap vent goes you the inlet, but I see your point. That's post MAF and will introduce more unmetered fuel? I want to get rid of as much emissions crap that breaks and is marginally useful (i.e.- TGV delete). Suggestions or sites you can point to? Sent from my Nexus 6P using Tapatalk Link to comment Share on other sites More sharing options...
sketron1 Posted May 21, 2016 Author Share Posted May 21, 2016 Thaks for the feedback, wasn't getting any. Stock subarus use PCV and coolant lines tack welded together under the manifold. That, along with the "PCV sensor" and that crap, was just begging to be removed. Can anyone point to a reputable resource for how to run the evap line, for offroad use of course. Link to comment Share on other sites More sharing options...
whitrzac Posted May 22, 2016 Share Posted May 22, 2016 Cap it off at the firewall. Link to comment Share on other sites More sharing options...
covertrussian Posted May 22, 2016 Share Posted May 22, 2016 Subaru is the first turbo car that I've seen have the PCV valve tapped into the inlet. Most other cars simply run the PCV valve to the intake manifold with a one way valve that closes under boost. I'm not against Subaru's routing, it uses the vacuum from the turbo inlet when the PCV valve is closed to reduce crank pressure along with valve cover breathers. 05 LGT 16G 14psi 290whp/30mpg (SOLD) 12 OBP Stock 130whp/27mpg@87 Oct 00 G20t GT28r 10psi 250whp/36mpg 22 Ascent STOCK Link to comment Share on other sites More sharing options...
sketron1 Posted May 22, 2016 Author Share Posted May 22, 2016 Subaru routes the PCV valve straight to the intake manifold, same as my crude drawing shows. They just include a Y and have the other branch going to the turbo inlet, some PCV sensor whose functionality/usefulness of questionable from what I've seen. Functions as a stopper with a sensor on ther. All aftermarket turbo inlets give direction to ditch it http://uploads.tapatalk-cdn.com/20160522/9be4a86388caf5cfd2b029ceea2fbd15.jpg I cut it off and mounted the PCV valve straight to the crankcase vent w/ a hose, clamp, and what see you cut off the Y http://uploads.tapatalk-cdn.com/20160522/40d8d9e0eb416763f09931962a8e5672.jpg Sent from my Nexus 6P using Tapatalk Link to comment Share on other sites More sharing options...
bigBADbenny Posted May 22, 2016 Share Posted May 22, 2016 What are you trying to achieve? Usually breather mods include either catch cans or AOS to prevent oil entering the inlet mani, reducing the octane rating of the fuel... The point of the Perrin inlet (at least the lgt version) is to increase air delivery to the turbo compressor, whilst maintaining Subarus exact config for the breather returns to the inlet, thus giving you the opportunity to preserve exactly the resultant vacuum differentials the FHI engineers intended for the breather system... http://forum.liberty.asn.au/viewtopic.php?f=18&t=23097 Shortish thread on the subject at Liberty Club discussing solutions from mishimoto and radium eng. Link to comment Share on other sites More sharing options...
sketron1 Posted May 22, 2016 Author Share Posted May 22, 2016 I'm trying to achieve simplification in that the "useless" PCV sensor is removed entirely, and the PCV goes straight to the intake manifold (as stock is setup) without all the hardlines under the intake manifold (since it was off anyway and they were corroded). Compared to my previous sketch, the only difference between mine and stock is the blue line going to the "useless" PCV sensor that every inlet manufacturer tells you to ditch. There would have been much simpler ways of going about this, but I'm OCD, unemployed, aircraft mechanic and engineer. Gotta have something to keep the mind occupied, lol! http://uploads.tapatalk-cdn.com/20160522/fd88d20663fcd0b33e314fc7841d5187.jpg As far as vacuum differentials and such, the Perrin intake is designed, port orientations and all, to be a bolt-in system so most existing lines are reused, etc. My system should have no affect on the pressure, etc. It's basically stock w/o the "sensor" at the inlet (capped off, not sure of function) Link to comment Share on other sites More sharing options...
sketron1 Posted May 22, 2016 Author Share Posted May 22, 2016 I think this is settled. I spent admittedly too much time looking at the stock PCV system and understanding it's function. I'll start a new thread on cleaning up the evap system. It's easily accessible so I'll save it for last to maximize comments and opinions Sent from my Nexus 6P using Tapatalk Link to comment Share on other sites More sharing options...
utc_pyro Posted May 22, 2016 Share Posted May 22, 2016 The way your diagram has it will basically make a leak around the throttle body. Ideal you'd have TWO check valves. Also not sure why you cut that hose... You can just uncrew the valve. It's just a check valve. Link to comment Share on other sites More sharing options...
bigBADbenny Posted May 23, 2016 Share Posted May 23, 2016 The stock Subaru breather system allows for the crank case to draw vacuum under both vacuum and boost conditions, the former via the inlet mani and the latter via the turbo inlet pipe. The heads breath in a two way fashion direct to the inlet pipe. That's the reasoning behind the 3 way joiner and the one way pcv vavle in the inlet mani, which closes under boost allowing the inlet pipe to vent the CCV. The group N VTA catch can is perhaps the simplest routing available: info in the ej207 info thread on nasioc... Radium's AOS routing is also simple, one can for heads n CCV with drain back to CCV and VTA or vent to inlet. Afaik all keep the pcv in the inlet mani. In your diagram, the 4th port should be the boost controller return to the inlet pipe iirc. The head breather pipes are teed together to vent to one of the inlet pipe returns Interested to see how your proposal works out Link to comment Share on other sites More sharing options...
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