How to: Set up your PCV, Catch Can, Breather, Vacuum system on your RB...

[Largekid]

Ok, I am working on installing a catch can onto the motor. I have already tapped the ports on each rocker cover to accept -an fittings, now am trying to decide on how to run the lines, and what to do with the PCV fitting. I have decided one of the three setups below would be best for me. I just have a question about the "best" option. I have read that if you block off the PCV it creates better vacuum, I have read to leave the PCV also.

I'm leaning towards fig 4 or the bottom, just trying to figure out if I should leave the PCV or not I guess.

[240z4u]

I use option 3 fwiw.

[Coolwhip]

For those who are looking to run -AN fitting on your valve covers:

RB20 and RB25 S1
http://www.rawbrokerage.com/raw-brokera ... rb20-rb25/

RB26
http://www.rawbrokerage.com/raw-brokera ... ings-rb26/

[RRRRB]

those are neat Ricky, to bad i have already tapped mine

[ANVIL]

why do a lot of people use that clear mesh hose with their catch can setup? i always see it and just wondering

[Darius]

why do a lot of people use that clear mesh hose with their catch can setup? i always see it and just wondering

It is usually provided along with the kits and people are too cheap to spend the money for -AN fittings and braided lines for something that doesn't gain any performance. After one season, I swapped it out because it turned brown and fugly.

[Coolwhip]

That clear hose also gives off it's own gas when it gets of temperature. I'm no expert but I don't think it's beneficial to engine performance having it suck that gas in through the air stream.

[RRRRB]

I have 2 -12's going right to the ground.. i have the inside of my valve covers baffled with stainless mesh.. it flows very well and there isn't even a hint of oil at the bottom on my breather hoses.. Although I'm sure the track officials wouldn't much care for how it's setup..lol

[ANVIL]

Can this setup cause any problems? Idle is low/rough and this and a bolt on turbo are the only things I changed... just curious if its something I need to fix in order for me to get tuned or if my tune will fix it

[Coolwhip]

If you changed the turbo you'll need to re-tune.

Regarding your breather it's not ideal. Proper vacuum isn't pulling on the crankcase.

[ANVIL]

^
Even with the pass side valve cover having the vacuum line to the intake manifold?

[Darius]

The vacuum line to the IM is only open when there is no boost and, therefore, very little blow-by. When the IM sees boost, the ball check in the PCV valve closes and any pressurization goes out the breather filter on the valve cover of your setup. Your setup is fine, but you have to make sure that filter stays clean because it can pass a lot of oil/water vapor and plug quickly causing lots of smoke out the tailpipe. Don't ask how I know this

Ideally, the tube where the breather filter is located would be connected to a catch can and rerouted to the intake ahead of the turbo inlet. OR run it to a fitting on the exhaust to use exhaust gases to draw the vacuum on the valve covers. My next car will be set up this way so I don't have to run a catch can. I'll just blow the oily residue out the exhaust haha!

[Coolwhip]

Note for the guys who are thinking about running their vents through the exhaust. If you have a restrictive muffler, catalytic, etc. you'll run into issues with pulling proper vacuum on the crankcase using this method.

[ANVIL]

Forgot to update but my idle issue was fixed when I moved my maf/filter farther from the turbo. Its got a low boost street tune that I have been running all summer and DD about half the time. Breather filter still dry... that's good right?

[Coolwhip]

MAF being too close to turbo will cause issues yes. Dry breather filters are always a good sign. Don't know how your setup is ran though to say.

[ANVIL]

Pic couple posts up. The line that used to go in the intake before turbo just has a breather filter. Reason I did is because the replacement pipe Im using with the new turbo didnt have anywhere to hook the line up and I haven't made one. Should I just connect that back and ditch the breather? Or am I good as is?

[ANVIL]

The original pic on the first post showing several setups is dead.

So i updated my setup and ditched the breather filter and ran that line from the exhaust side vc to the intake tube before the turbo. Im getting a lot of oil burn now and going to finally put in a catch can but undecided on what i should do. Im planning on running the the catch can inbetween the hose to the intake tube. Also undecided if i want to eliminate the pcv and plug the intake port or leave it and throw in a new pcv valve (anyone know us equivalent part #?)

Also debating on getting rid of the inlet to the intake but unsure if thats a good idea. Reason being if oil passes through i dont want it going back into the turbo. Or should i be good with the catch can?



Also im concerned under high boost my fitting on the exhaust side vc pops out. I was always wondering why the vc ports are so loose, what do you guys do to fix this? i see the AN fitting option but id like to avoid that to save some money not having to get the lines and fittings to work with those. Please help, all input appreciated...need to addess these issues asap so i can get in my final tune session