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Discussion Starter · #1 ·
Hey all,
Backstory - Built high comp engine and had a tuning adventure with this thing. First the MAF(late B15 style) I had was all over the place, so replaced it. Then when I was almost "done" with it all, my Innovate caca wideband I had was not working anymore. I went back to using Zeitronix and bought a ZT-3 wideband. Found that my AFR's were all over the place and appears that the Innovate wideband was slowly dying overtime and was giving me incorrect readings. Performed adjustments again, and got my AFR's pretty consistent, but overtime I started developing more knock. Got to the point that no matter what I did fuel and timing wise, it still would happen. I have been using G4 knock light, so I get this massive red light to the face when shit goes down, plus it was audible which made me nervous every time.

Found a post where I think Yogi shared his experience with no catch can or something and showed how much oil gets in there when driving modified QR25. Led me to research and found the Crawford AOS for Subies. After some more researching, I ended up committing to trying to use the AOS for a BRZ. Since they dont come turbo, I figured it was the best way to go. I also didnt want to have to worry about draining a ctach can since I do about 1200 miles a month commuting to work.
I installed the AOS as seen in the pics, and found that my AFRs were more consistent and made sense. Prior I was knocking at an alleged 14AFR. Now it was showing me 14.8+ when knocking was happening. I can only assume I was seeing richer AFR's because of the oil vapors going in the motor. I adjusted my fuel map and readjusted some MAF points and now I am happy to say, I did not knock once today :)

Only time will tell because I also had a little less than a quart of oil disappearing after approx 1.6k miles. So that would be even more of a confirmation that oil was getting sucked in.
SIDE NOTE - Found Stoich for E10, which is normal gas with 10% which everyone has, was actually 14.0. So tuning to that new concept helped out.
Here are the pics of what I ended up with. Just in case someone wanted to move on from catch cans. Updates to follow

173271
173270
 

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Battery goes in trunk, passenger side.
I'm more interested in the routing, where he put the distribution block, and how it's mounted. I saw older posts but most don't have pictures anymore

Also, that's an interesting way to route the catch can
 

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Discussion Starter · #7 ·
It is an Air Oil Separator(AOS) so the oil recirculates back into the car, unlike a catch can that requires you to empty it out when its full. . It the same concept Porches use. I was actually looking into putting a Porches AOS in the car first lol.
As far as installation, I did not need a distribution block. I just followed the picture what goes where, cut the bracket, cut part of the tube to clear the strut bar and installed.
I had to order two PCV hoses with right angles so I can redo the lines better and also some silicone vacuum tubing. I had to use some fuel line and some heater hose. It was temporary and proof of concept for me lol
For the bracket, I cut up some metal and welded a bracket together to mount to the firewall. The passenger bolt hole already had threads from the factory, so the driver side bolt, I drilled and installed a rivnut and bolted with 1/2inch spacers. I have rivnuts holding the AOS to the bracket. I also had to bend the brake booster port down to clear the bracket. This also required me to order a brake booster hose from amazon for a chevy. Has the right angle i need, and its super long so I can cut to size. The factory hose is one right now, but not how i like it. This is revision B, revision A was actually going to go on the side of the head, but hood clearance was impossible
 

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Discussion Starter · #8 ·
I also tried to keep both the PCV port and also the Valve cover vent tube higher than the engine as much as i could without hitting the hood. For Subies and BRZ, motor sits way lower, so they dont have to worry about that so much.
 

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Nice info man. The Crawford is definantly top notch. The catch can I have, cent remember the name, has a drain at the bottom where you can routs a hose back into the motor using either the dipstick tube or a drilled hole in the upper oil pan.

Its amazing what a good pcv system will do. The newer VW cars suffer from a shit ass pcv system built into the valve cover and causes major issues.
 
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