vmapper

iTrader: (8)

None of these suggestions would work if your running an MAF Blow through tune...
actually, none of these appear to work properly with any MAF vehicle as any air pulled around is un-metered, is everyone SD?... is there a different setup to accommodate for this? or am i missing something here...

I would think a crankcase vacuum scavenge external pump system was the only way ESPECIALLY when you start putting 'cute' k&N's somewhere to the atmosphere.

Sorry if I dug this out of the grave...

05TurboCGM

The amount is very negligible and the computer will adjust, this topic has been beaten to death.

vmapper

iTrader: (8)

Im sure Banish would dislike this answer.

Negligible? Really? Last time I changed to and open PCV the idle went haywire, did a scan.. and the computer pulled timing big time to bring it back... thats becuase its UN METERED air. Maybe a pinhole, but your talking a considerable CFM count. Every tweaked table would be out in regards to cylinder volume and the Proper tune is out to lunch.
As mentioned... NOT running SD, but MAF only... I would not compromise, espeically on a blown car, to 'LET the computer handle the 'un' metered air leak.

So your HOPING, ONLY if your in Closed loop, that the Narrow band O2s see this extra air and enrich?

I think if it was beaten to death and the conclusion was 'negligible' and the computer was to adjust is a naive conclusion and clearly dont know the details of the ECM.

eodmonkey

so this was a tad dizzying to a pcv layman like me. also i'm more of a visual learner. so like is this what most of you would agree works.

vmapper

iTrader: (8)

Well, when I look at that diagram I think,
It would work if you are running SD (Speed Density Tune)...
Will not if your running with a tune that uses a MAF.

And again.. I want to know why 05TurboCGM likes to create vacuum leaks for his ECM to adjust for, causing the inability to get the BEST out of a tune... I wish Greg Banish would post on this.

Bad30th

iTrader: (13)

No need for Greg Banish to come save the day, LOL. My setup doesn't allow unmetered air (which is one of the reasons I don't use a breather in the PCV system). Post #49 in this thread. There are a million ways to do this, and a million different opinions on how to do it. This topic gets beat to death.

Just like every other post on this board, read and make an educated decision for yourself.

Rob (Bad30th)

eodmonkey

so what would you change for a maf setup? from my understanding at idle the setup would work as normal, fresh air in the blue line and vented to the throttle body by the red, then under boost the check valve would close off the one line but the turbo would pull the crank pressure through the blue line and recirculate it back in through the maf? where would the unmetered air come in?

vmapper

iTrader: (8)

Rob, can you help me understand where the air is drawn from the crankcase when your at full throttle and the vacuum path is being pulled from the passenger valve cover?
what Im saying is, where is the fresh air coming from? or are you actually creating a vacuum within the crankcase? (not a ventilation so to speak and then creating a vacuum in the crankcase via manifold during light throttle and idle.
Like a double sided vacuum? - I suppose that would work, not really circulation of air.. but always under vac?
Am I understanding that right?
You dont need to re-explain.. As I see you have done a decent job prior, and what I wrote above is what you are getting at. an Actual Vacuum vs circulation.

vmapper

iTrader: (8)

The air is being pulled PRE-turbo (your blue line), thats un-metered air that is let into the manifold during idle through the catch can.. through the crank case then the check valve into the manifold... bypassing any MAF setup.
In pressurization, its dead.. check valve preventing circulation and you create a vacuum in the crankcase... I guess is fine.. but idle (high manifold vacuum) its pulling air pre-turbo.
Thats what i get out of that diagram... only works half time.

Aster

iTrader: (9)

What would you suggest for a post MAF fresh air source that doesn't pressurize your crank case under boost?

Besides the vacuum leak doesn't exist under boost.

eodmonkey

ok, so at vacuum the blue line is just like having a breather attached. i guess thats where the sts setup uses the pressure switch and bypass valve?

eodmonkey

this may sound stupid but, whats the deal with evo's n sti's pcv vs ours?

vmapper

iTrader: (8)

the only conclusion i can come up with is install a Crank case vacuum pump system. You can not go Post MAF as that is bypassing your metering via crankcase, especially someone running MAF only based on values in the ECM. I guess go SD and tune the 'leak' in is the other alternative.

Here is over 800 posts of hell:
http://www.iwsti.com/forums/2-5-lite...ns-thread.html

ss.slp.ls1

iTrader: (36)

I think if you also had a catch can in the line that goes to the intake manifold as well, then it would be a good pcv system.