Dual Catch Can Install
The background behind this mod but in summary is I found my Grimspeed AOS worked fine on the street but at the track it was not doing its job so I decided to move to a catch can. Lots of research later I decided to do a dual catch can setup that would 100% retain the standard function of the Subaru PCV system.
This is my proposed hose routing
There are lots of catch cans on the market, some are junk, some are overpriced and some are overpriced junk. This lead me to Saikou Michi catch cans, he is a one man show building fully customisable catch cans to order at very reasonable prices. By using Mr Saikou I was able to get the hose fittings done in the sizes I wanted and get the drains and mounting bracket in the right spot so I could mount the cans where my battery used to be. The hose fitting sizes I have made to match the stock size connections for the entire system so we don't get any bottle necks.
One month later my custom cans where delivered to my door, the quality is top notch.
So I started pulling the car apart to fit the cans, hopefully this will be a thing of the past.
Here you can see the oil seeping out of the three way joiner from the crankcase. This is not the PCV on my car, my PCV is screwed into the intake manifold under the throttle body.
Here is the PCV, this location makes no difference to my intended routing.
In the RHD cars we have the brake booster sitting where you guys normally mount these cans, I had plenty of space where the battery was. Time to mount the catch cans, I traced the shape of the mounting bracket onto paper then checked to make sure there was no wiring behind before drilling the holes.
I used some stainless bolts with extra nuts so once done up I would not have to reach behind the fender liner again if I wanted to remove the cans.
The cans fit really neat into this location and I can easily slide a dish under them for draining.
Now back to the hose routing, things are really crowded down here so I took the opportunity to do the throttle body coolant bypass mod to make a little extra room. To do this I simply removed the coolant line from the bottom of the throttle body and joined it back up to where the coolant line from the top of the throttle body comes up from the block. I then completely removed the hose that joins to the top of the throttle body and found it was the perfect shape to use in my catch can install.
A picture tells a thousand words. Here you can see I have the three piece joiner on its side with that former coolant hose going back up to the turbo air intake. The 19mm hose goes to and from the catch can and I shortened the other hose going to the PCV. This is exactly the same as factory except now we have a catch can grabbing the oil vapour before it goes back into the intake manifold or air intake.