once again trying to wrap up and get the fd on the street. for the catch can i am running a line from the filler neck and another from the rear oe turbo return block off plate. am i missing anything and is it better to just vent the can or run a pre-turbo line to add negative pressure to aid in the evacuation of the gasses? all recommendations welcome.

 

hey man... maybe im just stupid but, ive been reading all the how to install a catch can threads and they are all different. some people say install from the pcv valve to the tank then from the tank to the primary turbo intake elbow. then others say no dont do that because youll "soil" your intercooler. then others say tap the filler neck cap...

im confused. if you dont mind, could you show me where you have your lines from your catch can routed and how? like inlet from here like this and outlet to here like this?

 

would be happy to but the motor is out of the car right now while i clean everything up. all i have been doing is mock ups as i am running everything in an line and fittings and want to make sure i have everything i need when i start reassembly. also this is a single turbo setup. i am planning on just venting the can but wanted others imput.

 

and once its done i will be a total pic ***** i promise. after a drive of course as its been down 18 months

 

I have my catch can connected to the filler neck, with a small breather filter on the can itself. Just one line, nothing else.

 

I run mine a couple of different ways and the best way so far for me is to run a hose from the fillet neck to the large nipple on the upper intake manifold right after the throttle body. I put a check valve here so that it only sees vacuum. I put a T right before this check valve that then goes to the intake pipe right before the turbo with another check valve oriented to flow opposite of the first. This way you always get vacuum at the filler neck. No oil pan leaks, no catch can, and very little oil in the majority of the intake piping!

 

I just run a line from the oil filler neck to under the car. Don't have the room for a catch can.

 

ah i found what i was looking for in the single turbo section. i swore i had read threads on this just couldn't find them. search fail

 

just a fill? no return?

 

the rotary does generate significant crankcase pressure when run hard and it needs to be vented. i remember reading one of the longest threads on the board on the "fix" a few years ago...

all kinds of elaborate baffles etc. do it right and you don't need no stinking baffles.

the bottom line is the motor needs to be vented on both sides of the block. the OP has the "fix" right....

"a line from the filler neck and another from the rear oe turbo return block off plate"

isn't it great that Mazda thoughtfully provided a perfect vent on the pass side.

i run a 90 out from the pass side and up to a 90 at the top of the block and over/across to my accumulator tank which has a small hose at the bottom that runs to the back of the car. i also run a line from the oil filler to the (small) tank.

if you just vent the filler/driver's side, you have no venting in right hand turns.

i do not like running any of the carbon filled dirty 4 cycle oil thru my motor. see "save the whales, save your motor" in the 3rd gen section for details. needless to say i do not run the external oil pump and i do premix.

hc