I pinged the guy one more time. If he doesn't get back to me in a day or so, yeah, just forget it.

Sorry if it doesn't go through (though I still hope it will!), the guy seemed into the idea originally.
-Abe.

P.S. Fred, you can have them in a year, but you'll have to come pick them up.

Yeah what's happening?

abe shops at shirt.woot.

Clever, but no. I have friends who do.

Ok, so... Thinking about the catch can thing, I've never really come up with something I like.

I assume, idealy,
1) the valve cover always has flow through it.
2) the best place for those fumes is the intake manifold
3) a catch can is needed between valve cover and "vent to atmosphere"

And two things I'd like to see, but am not so sure on:
4) A catch can on BOTH manifold vents is best
5) venting to the air cleaner is better than to the atmosphere

Anyway, here's a couple things I was looking for:

http://abefm.smugmug.com/photos/335866155_sXAkz-XL.png

From 4) above I think two cans is what I want. And the problem with Method #1 is that it doesn't follow 1) above.

Anyway... I'm curious about people's thoughts.

Explain to me why you would need a check valve venting to atmosphere?

I'd personally want both the check valve & the pcv valve.....to the IM, the end.

Abe, based upon your ideas/contributions, I made this beauty (I think it's like your first example):http://i258.photobucket.com/albums/h...narot/vent.jpg

If manifold vacuum is present, then we'd see crankcase gas evacuation. Win.

In boost, the manifold would be safely sealed AND crankcase gasses would have the ability to VTA. Win and Win.

However, one problem I see right away (in boost) is that the crankcase gases must overcome the resistance in check valve #2, which, depending on check valve design, would possibly result in "high" pressure in the crankcase.

If no checkvalve before VTA, then in vacuum conditions, fresh air would be drawn INTO catchcan and into mani.

i fail to see the need for two check valves....

youll still want the pcv.... or straight up fuck anythign running to the IM.

try this. gut your PCV and try to idle the car, shit will run like asshole with the big as vacuum leak you've created.

so a pcv like normal will prevent that, and allow the fumes to be burnt off like a good boy. the check valve will prevent any boost from entering the catch can or crankcase....meanwhile to crankcase will be open to atmosphere through two ports....

+1
Your backwards check valve arrows crossed out weird me out. :-) But your pictures are very clean!

Anyway, to the actual point, yes, you'll have a vacuum leak if you just let the mani see the atmosphere through the catch can and the crankcase. Is it enough to be a problem? I dunno. But that's why I have the checkvalve, so that under vacuum there's no leak.

I'm just hoping the check valve to atmosphere doens't have a lot of resistance... And I'm hoping that not flowing air through the valve cover is ok.

I think the issue with no cross flow is you're not really flushing out all the moisture you could be, which translates to oil that doesn't last as long. So far all my best ideas involve way too many catch cans. :-) I guess under boost you can live without cross flow.

I really think running to your intake tube is a better idea than venting to atmosphere. Chucker's drawing looks reasonable beyond that.

then why bother with a line to the IM at all? vacuum will always keep it shut...thus never venting... kinda defeating the purpose..since it's during low vacuum the pcv opens and draws air in from the crankcase.. if no line is present to the IM, no boost can go into the crankcase, and no need to bother with any check valves.

Um, are you claiming there's some difference between a "PCV" and a check valve?

The idea is so the manifold can suck on the catch can (and therefor the valve cover) but not suck from atmosphere (which I'm undecided if it's a good idea), nor can boost pressure blow into the crank case. Hence the two check valves.

i am claiming there's some difference...

http://boostedmiata.com/technical/pcv-operation.gif


during both high vacuum AND boost it's closed.

Ok, that is interesting! I didn't know that!!

I'll revisit my drawings a bit, but I think that's going to be a big help! Something along the lines of switching the two valves in your drawing seems to do it for me... Soon, very soon...

hmm. i'm following this thread a bit more closely now. went out for a spirited run with a lot of high end cars on saturday, and it involved a lot of running at high rpm and a couple extra pounds of boost. by the end of a couple hours drive, i was producing a good amount of oil smoke from my tailpipe (at least half a dozen people made sure to mention the car was smoking pretty good...).

when i finally popped the hood after getting home, there was oil everywhere that it could possibly get to from the breather on the driver's side of the motor. popped the hose off the PCV and there was oil all in and around that as well...

question is, think running a double vented catch can like the original post, and plugging the IM port solve my issue for now (assuming i haven't done the rings in?) while i wait for a couple of those fancy check valves to come in the mail?

I doubt you harmed the rings, at least, not from the oil directly, but I guess potentially from detonation if the oil coated the intercooler and/or diluted your octane rating significantly.

i doubt it too, but i generally am just a huge vagina and assume i am blowing my shit up every second i'm driving the car :-)

Do wash out your intercooler with solvent before thrashing it hard again though won't you?