I may sound like an idiot but I guess that is the only way to learn. I install a greddy catch can into my 05 STi. I finally got it mounted up (much harder than it looks) and after digging through dozens of posts figured out how I want to plumb it in (I think). But I do not know what this sensor (arrow) is on the crank vent that plumbs in just before the turbo inlet. It was not in anyone else’s photos. So here it is.


Close up of censor


A bit further back


and I was going to leave the PCV (it is the PCV right?) alone because it only draws a small amount of vapor and only when the intake has vacuum. Correct?



Does my plumbing illustrated in red look correct?

Thanks for the help.

-Mike

 

That's the PCV sensor. Don't disconnect it. Don't leave it open to atmosphere either.

IMO, you should run two separate catch cans if you really want to scrub both of those lines. Alternately, you can just hook up the rocker vents (the ones that are bolted to the TMIC).

 

If you go and take a look at scoobymods.com in the forester section you can see how it is done. With either 1 or 2 catch cans.

 

great, thanks for the info. Why can't i just run one can and T in the PCV sensor line that comes from the block to the "in" and line to the sensor to the "out" side of the can? here is a picture to better understand what I am talking about

 

You can do that if you like. There are two schools of thought and if you do a bunch of searches you'll see what I'm talking about. One idea is that what you proposed is just fine. The other idea is that since the PCV and Rockers vent at different pressures and different times, they should be separated a la using two catch cans. This is how I have my STi set up. I'll post some pics a little later as they're on a different computer right now.

 

Sounds good. Does anyone know what exactly the PCV sensor does? Is it simply a sensor, or is it some type of solenoid valve? I want to better understand the PCV before I make any decision.

My current thought is that although the PCV and crankcase vents operate at different times at different pressures they both operate off the same vacuum source, the intake. So if I T both the PCV and the crankcase to the can, then apply the intake vacuum to the can it should yield the same results, no?

The only potential problem I see now is that by placing a T just after the PCV sensor and hooking it to the crankcase vacuum source I am effectively applying vacuum to both sides of the sensor. One from where it plugs in stock and 2 from the T, illustrated in blue (PIC)




Once we get this all worked out I will make a nice diagram for all to refer to in the future.

Thanks again,

Mike