So like the title says, What would happen if i installed a catch can and routed the pcv valve to the can instead and sealed the spot where it connects to the manifold? What useful purpose does the pcv valve serve anyways?

The PCV Valve is the positive crankcase ventalation valve. It is there to vent the pressures from the crankcase to the manifold. I believe I have heard of people putting catchans there, and and having it work fine. I'm not exactly sure though. I am sure someone else will clear it up a little.


-Nate



________________
-98 Avenger I4 5spd
-ALL MOTOR build up in process
-Mods: AEM Front Big Brake Kit, AEM CAI, Bosal Header

Next Mods:
Bored Throttle Body, Ported Intake Manifold

I've done this, and I haven't had any problems.

If you can put a breather there, you can put a catch can.


Lane Adams

stock 95rs=backroad rally champion

I've got mine going to a catchcan.
If you do this and the EGR blochoff and put a breather between your VC and intake pipe you have no dirty shit going into your intake. This would be very good if you P&P your intake and bore your TB, because they would be clean when you put them back on and stay that way.

so whats the deal. doesnt the intake manifold push air into the crankcase? I guess not though cause the other side most people have ran to a catch can anyways... anyone with some more insight on this please chime in cause i'd sure like to use that vac source for something else.

I believe the point behind PCV is to use engine vacuum to pull fumes from the valvecover into the intake manifold to be burned. I personally have my PCV blocked (but still attached) to keep crap out of my intake manifold. I have a vented catchcan on the other valve cover vent.

Corbin

'95 ESI-T
HRC+FMIC+ETC...



Gimme fuel...Gimme fire...Gimme that which I desire

how did you get your cars to run fine w/ it removed? a couple dayz ago i removed the valve to test to see if the valve itself was working and the car ran like crap. it's idle was all over the place and it was really bad. is there something else you need to do to make it run w/ it off?

Having an RRE catchcan w/ an inlet on each side. Couldnt I just run a vac line to the other inlet of the catchcan, and use the vac source off the manifold for something else?

I have both nipples coming out of the valve cover teed together, then run to one side of my RRE catch can. The other inlet on the catch can is still plugged. And the nipple on the intake mani where the pcv valve used to be is also plugged, but I suppose it could be used if you needed another vacuum source.

Just out of curiousity, what do you need another vacuum source for?

>Just out of curiousity, what do you need another vacuum
>source for?

I'd like to simplify the "t"'s I have, and maby use that vac source for the fuel press reg. Plus I dont really want it getting sticky oil all over my nice port job.

>how did you get your cars to run fine w/ it removed? a
>couple dayz ago i removed the valve to test to see if the
>valve itself was working and the car ran like crap. it's
>idle was all over the place and it was really bad. is there
>something else you need to do to make it run w/ it off?


You need to plug off the intake inlet when you unplug the pcv hoses.

Corbin is right on. Vacuum is used from the intake mani to relieve fumes and excess crankcase pressure. The valve is on there to prevent anything going into the valve cover from the intake manifold. However, when we add boost to the system, it gets a little different. The PCV valve is not air tight when the car goes into boost (some of them are reeealy leaky). This can cause a slight boost leak there and also feed the valve cover with some pressure which is vented out the other breather. I would say the perfect solution for this problem is to put a catchcan in the line between the valve cover and the PCV valve. Then put a really good check valve in place of the PCV valve so that the valve cover will still see vacuum, but not get fed any boost. Do not hook up the valve cover breather to the same catch can in this case because then when the valve cover saw vacuum from the PCV side, It could not allow air in the other side to equalize the pressure.

I have my pcv outlet and the valve cover breather going to my catchcan. The port in the intake that once went to the pcv valve is now the vacuum port for my bov and mbc.