Hello Everyone,

I was cleaning up my engine bay, and was looking and check all my piping and looking for leaks. going to passenger side and I looked at my piping going to my catch can and thought to myself something isnt right.

for those with oil catch can or not. there is a pipe going from the front of the intake manifold going to the pcv. which is where we usually see oil from the manifold and is the reason why we use a catch can.

Since Naturally asperated vehicles never see pressure that set-up would be fine, if you added a catch can running from the manifold to the can and back to pcv.



vavle covers need to release pressure that are created gas ect. but I have noticed that when your FI'd your creating pressure and with this set-up your adding pressure where its suppose to be released! creating stress and heat to the cams.

so, correct me if I am wrong but shouldnt we has the lines routed from the intake pipes rather than the manifold?

 

in your lower circle that hose is connecting to a PCV valve which is a one-way check valve. unless it has failed, it will not allow boost pressure in. but ya, the effectiveness of the PCV system is reduced once your in boost with this factory layout

 

https://my350z.com/forum/forced-indu...illed-oil.html

https://my350z.com/forum/forced-indu...?highlight=PCV

https://my350z.com/forum/forced-indu...?highlight=PCV

https://my350z.com/forum/forced-indu...?highlight=PCV

 

thanks for the links. what I ended up doing is capping the front vacuum source located to the front of the manifold (top circle in the picture) and from the pvc to a catch can and the other side just dumping atmospherically now.

I will route that to a intake pipe to create suction for the catch can soon.

the car revs alot faster and pulls alot stronger.

 

Just so you know, I had issues with -ve load conditions with a setup like this (not pulling into the plenum), just something to think about ...

 

sometimes it idles a lil funny, but i am running on the SS box. nothing fancy, I will be getting Haltech when I finish up my spare forged block build.

 

If anything, I would just install a check valve in the hose between the plenum and the catch can (or PCV valve, if you aren't running a catch can).

http://www.usplastic.com/catalog/var...riant_id=64175

This way, you'll still have vacuum pulling from the crankcase when non in boost, but you won't pressurize the catch can and crankcase in boost.

 

For those looking for check valves.

APS part number 000-990-300 VALVE - ONE WAY - PCV
http://www.airpowersystems.com/guide...-tts07/bom.htm

OEM Nissan brake booster check valves off a Z32
$20 from courtesy parts =

http://www.courtesyparts.com/kb_sear...utton=Go&cat=1

1. [47478] VALVE ASSY-CHECK - Product SKU: 47478-Z32001
2. [27461M] VALVE-CHECK - Product SKU: 28628-Z32001


OR:

http://www.partsgeek.com/gbparts/199...ek+Google+Base

 

I just capped the hole in the intake manifold and ran a line to the inlet of my supercharger with an inline catch can. Worked nicely!

Just a picture of the line run from the inlet to the catch can during the build process.