PCV System, will this work??

[KaLo_o]

Ive searched lots of threads on the pcv system, so far to me the 2 catch can system with a check valve is the one im aiming for. now i just have a question on that one, insted of keeping the stock pcv vavle, why not just eliminate it?? would this work by just putting an open nipple fitting and just putting a check valve inline? why keep the pcv valve if there is a check valve in there??

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[ilco187]

seems like it would work, but you dont want the oil hoses that low you want them up high.

and yes you can eliminate the stock pcv and get a check valve just make sure it can hold like 20 psi just to be on the safe side.

 

[kchaazz]

That is the exact way Ive got mine set up. ENSURE both cans are air tight or you will have issues, especially on the can attached to the intake.

 

[99gst_racer]

Looks good to me.

The factory pCV valve sucks, so a good check valve is a great option.

 

[KaLo_o]

cool, as for the oil lines being low i was gonna run it that way to make sure the vapors stay low in the cans that way i get the ''fresh'' air at the top and those lines are for the intake manifold and intake pipe. i will have to clean the cans often thats all

 

[95TalonOwner]

If you have the oil lines that low, the pressure of the oil in the catch cans will force the oil through those bottom lines back to the motor.

 

[KaLo_o]

ill probably have them setup at the middle of the cans, i just made a quick diagram, thanks for the info tho. where could i order a check valve? preferably one that is the same size as the stock hoses for the pcv system...anybody??

 

[gixrman]

ill probably have them setup at the middle of the cans, i just made a quick diagram, thanks for the info tho. where could i order a check valve? preferably one that is the same size as the stock hoses for the pcv system...anybody??

Go onto Amazon and do a search for automotive check valves
Amazon.com: Automotive Air Check Valves

 

[snowborder714]

Check Valves | U.S. Plastic Corp.

 

[chaggard27]

You could also use a check valve from like say a pool or something like that. Those usually can hold quite a bit of pressure

http://www.amazon.com/SHURflo-340-001-In-Line-Check-Valve/dp/B000BGJWF2

there is a good deal and holds up to 100 psi

 

[KaLo_o]

ok thanks guys....and one more question....

lets say i hoop it up this way BUT, i dont hook up that one line to the intake pipe and leave it in a vented catch can and plug the nipple on the intake pipe.... would this cause a problem with ''mesured air'' leaving the engine ? i am not quite sure from where the air from that side of the valve cover is coming from...

 

[chaggard27]

Valid point since this is the same thing that causes problems with bov vented to atmosphere. I would say that in this scenerio however you would be fine since it is such a small amount of air that will be un accounted for. Also since it is vented catch can air can still come back in when there is vacuum...it would just serve the purpose of keeping the pressure out of the valve cover

 

[KaLo_o]

right!, im really curious of where the air from that side of the valve cover is coming from (intake pipe side)... if its coming from the crankcase then is should not be ''mesured'' air right? since mesured air only ends up in the cylinders via all the intercooler piping etc...

also, how does the air get metered from the PCV line into the intake manifold? i mean.... the air is getting pulled from the crankcase and into the intake manifold...how does the MAF even read that?? is the ECU setup to already count that air in or what?

 

[95TalonOwner]

Air in the valve cover is from blow by otherwise known as positive crank case pressure. Any air that is in the valve cover area was already measured by the MAF. It does not get measured when it gets sucked back into the intake manifold.

 

[SOADweskey]

You should check out these guys for a quality catch can that is actually designed to trap oil in it.
Saikou Michi Co. Home Page

Here is a diagram of what the inside of their cans look like.
Saikou Michi OCC Explanation

I use one in my car between the valve cover and intake pipe. It does a good job of filtering out the oil and I can still use the vacuum created in the intake pipe to suck air out of the crank case.

 

[chaggard27]

As posted above the pressure in the valve cover is from blow by which is in essence metered air...but it is accounted as used once in the cylinders so it would have no effect if lost after that. The idea of the vented catch cans is to use one can for the same idea you had initially. Instead of having two extra lines to go to the intake and also the inlet pipe it would just be vented out to atmosphere so you would just plug both the intake nipple and the inlet pipe nipple and call it a job well done! Much easier if you ask me!

 

[KaLo_o]

As posted above the pressure in the valve cover is from blow by which is in essence metered air...but it is accounted as used once in the cylinders so it would have no effect if lost after that. The idea of the vented catch cans is to use one can for the same idea you had initially. Instead of having two extra lines to go to the intake and also the inlet pipe it would just be vented out to atmosphere so you would just plug both the intake nipple and the inlet pipe nipple and call it a job well done! Much easier if you ask me!

the problem with that is you wont have any vacuum to suck out the air out of the crank case, i currently have mine setup as 1 catch can and both valve cover nipples are connected to that vented catch can. its not a great setup at all, im getting lots of blow by and thats why im gonna change that setup. if you have 2 sealed catch cans and a check valve, you can use the vacuum to suck in that crank case pressure and stop the oil from recirculating in your engine

 

[chaggard27]

Correct me if I am wrong but I thought that the only reason it had to hook into the vacuum on the intake was just to relieve the pressure to some place. If it wasnt vented or tapped into the intake then the catch can would just build pressure along with the valve cover. So in theory the vacuum isnt really sucking in the air since the pressure is pushing it out into the catch can. The pressure is just relieved into the intake thus lowering the pressure. So with the vented it just vents to atmosphere instead of the intake. Which would actually probably give you better performance since you are not putting hot compressed air from the engine back into the intake....hmmmm

 

[DGajre777]

With that check valve in place and a open nipple fitting (hollowed out PCV), I don't see why you need a 2nd catch can. Without a 2nd catch can, whatever oil fumes or vapors you have at the base of the check valve will get sucked back in when the crankcase has vacuum.

I have my line going from the OEM PCV Valve > Check Valve > Intake Manifold. It is a regular PCV valve that I replace every time I get an oil change. Now that I think about it, I wonder why I didn't replace the PCV valve with an open fitting or drill out the PCV.

 

[KaLo_o]

Correct me if I am wrong but I thought that the only reason it had to hook into the vacuum on the intake was just to relieve the pressure to some place. If it wasnt vented or tapped into the intake then the catch can would just build pressure along with the valve cover. So in theory the vacuum isnt really sucking in the air since the pressure is pushing it out into the catch can. The pressure is just relieved into the intake thus lowering the pressure. So with the vented it just vents to atmosphere instead of the intake. Which would actually probably give you better performance since you are not putting hot compressed air from the engine back into the intake....hmmmm

I'm not quite sure what you are saying,please specify intake what?manifold? Or pipe? If u don't specify I can't tell what nipple your talking about. About the vented catch can...performance wise it's true that you won't be pulling in hot air with fumes and thus reducing air intake temperature (slightly) but true fact. But I know that the single catch can connected to both valve cover nipples is NOT a good way to relief crank case pressure.if you do enough research on the pcv system you will find out. The reason why I want a 2 sealed catch can setup is to create some vacuum in the system to really relief the crank case pressure after hard pulls and for the intake pipe side,you have to use a sealed can since if it's not sealed you are going to let unmetered air into the engine. Also it's good to have some vacuum on that side of the valve cover since the intake manifold side will be shut under boost. I could block of the nipple on the intake pipe and run the valve cover nipple to a vented catch can, but I like the idea of creating vacuum as much as I can. I wish I could post some links on the pcv system but I'm on my iPhone. Basicly the pcv system on our cars need help when running lots of boost and power,it wasn't designed for high horsepower applications. Right now my car is running about stock power and when I installed my single vented catch can to both valve cover nipples... My car had started to get lots of blow by, and that's with a open Mille instead of the stock pcv valve... That's enough info for me to know that my pcv system is suffering on that setup.... I want vacuum back into the system,no doubt about it

 

[chaggard27]

I was just throwing out different ideas for the setup. I have not researched the pcv system at all just basing my input off of logic and information I have aquired through the reasearch and work I have done. So I wouldnt do what I said ony based on my idea. Like you said you have done the research to back up your theory. I would say go in that direction since it would most benefit you in your setup. I personally like the single can just to free up space and keep things clean but that may not be one of your goals on your car. However is there really that much vacuum created from the valve cover? I mean logically there would be pressure yes...which would let air out of the pcv valve, but if there were vacuum created then I would think it would have to be quite a bit of vacuum to open the pcv valve and then suck air out of valve cover to then create a vacuum in there and thus make it require even more vacuum to open up the pcv valve again unless a pressure is introduced back into the valve cover...does that even make sense? . It does in my head but then again it is dark in there

P.S. intake as in intake manifold in the above post. Sorry for not specifying, Also since you have MAFT-Pro why dont you run speed density and then you wont have to worry about any vacuum issues. Makes life simple

 

[DGajre777]

This is what I run!

 

[KaLo_o]

its all good man, yeah well im just tryin to have a setup so that i dont have to mess with it again, as for the single catch, if thats what you want i would get a SEALED catch can, put an open nipple fitting where the pcv valve goes, route that line to the catch can, and for the second line just run it to the intake manifold with a check valve inline. and as for the side valve cover nipple just run a hose on there and route it under the intake manifold and let it vent to the ground. or just throw a little breather directly on there. its up to you if you want to have a sealed catch can or just one with a filter on it.

right now i run a jm fab deluxe catch can (unsealed) and its really not working for me like i mentioned...and im running 12pounds of boost and stock intake and MAF so yeah....very poor breathing in my crankcase with the filter style catch can. and the dam thing is big for a catch can!

heres an interesting video....also read up of the comments at the bottom

PCV improvements and testing for DSM - Car Videos on StreetFire

about my MAFT pro, its not hooked up right now, but i cant wait to hook it up, right now im just running stock maf and no boost controller so around 10-12 pounds. i just want to have good crank case venting before i turn the boost up and start tuning with the maft pro!

also there are lots of threads about how you should use a sealed catch can to keep the vacuum in the PCV system. just look around on google and dsmtalk.com

I only started having crank case pressure problems when i instaled my unsealed/filter style catch can... i regret buying one cause now i want 2 small sealed catch cans.

my oil looks like shit and my oil smells like blow by yuuuk

This is what I run!

very nice...pretty much like my setup but a fuel filter inline and an extra check valve so that air from the valve cover nipple dosent make a shortcut to the air intake pipe! i love it man!

 

[AG 305]

this is similar to something im asking in my thread here

http://www.dsmtuners.com/forums/bolt-tech/387244-catch-can-pcv-vent-dd.html

if the intake pipe is really needed then how do those street cars running SD or a standalone system with no intake pipe relieve crankcase pressure without using vacuum from there? im sure NONE of them want any excess pressure or blow by.

 

[KaLo_o]

this is similar to something im asking in my thread here

http://www.dsmtuners.com/forums/bolt-tech/387244-catch-can-pcv-vent-dd.html

if the intake pipe is really needed then how do those street cars running SD or a standalone system with no intake pipe relieve crankcase pressure without using vacuum from there? im sure NONE of them want any excess pressure or blow by.

easily... from the valve cover to the intake manifold just like all the other cars out there! the intake pipe side one is just a bonus, since under boost the pcv valve is CLOSED to keep pressure out of the valve cover, the engine will suck out the pressure from the intake pipe being under vacuum since the turbo is spooling!

the intake pipe is not ''needed'' for this, its just an extra way of relieving pressure in the crank case....i will definily have 1 or 2 lines hooked up to my intake pipe to draw pressure out of there under boost since the intake manifold side one will be shut under boost