what to do about pcv valve from boost
 

what have yo all done about your pcv valves to keep boost from getting into the crank case and blowing seals

Re:what to do about pcv valve from boost
 

if you've learned how a basic pcv works on an n/a car then this diagram will make perfect sense to you:

http://www.beesandgoats.com/boostfaq/PCV_turbo_2fit.jpg

Re:what to do about pcv valve from boost
 

um, the pcv valve prevents the boost from getting into the crankcase.


it gets its name due to the fact that it is a 1 way valve. it lets positive pressures out the crankcase, but it doesnt let them in.

Re:what to do about pcv valve from boost
 

most people run them stock and then the pressure builds up then -> no more rings or something else will blow up. Typically on a n/a car a bad pcv valve will ---- your valve cover gasket or worse.

Re:what to do about pcv valve from boost
 

well. you have to make sure they work. that is what they do.
there are hand pumps to test if the valve is leaking or not.

Re:what to do about pcv valve from boost
 

^^^^
yeah that would be called put it up to your lips and blow/suck on it to test for function :P

Re:what to do about pcv valve from boost
 

so you're speaking from personal experience. :) i have a brake bleeder/vacuum tester with guage. it can hold the pressure for awhile to see if small leaks are present. it can also be used to test for pressure. we used it to see what psi actuators were set at. very useful imo

Re:what to do about pcv valve from boost
 

I had one of those until I used it to bleed brakes.. was fucked after that for most practical vacuum uses. Yeah man, don't be afraid of a little oil.. never hurt anyone

Re:what to do about pcv valve from boost
 

seriously man, take it out and blow and suck through it, air should pass through only one direction, if it doesn't pass through at all, it's time for a new one. they're only like 3 bucks.

Re:what to do about pcv valve from boost
 

I just love it when you talk dirty :P

Re:what to do about pcv valve from boost
 

I looked at your picture....am I understanding correctly that if you don't change the PCV setup, there are potential problems from it...like the rings giving up sooner than they would with a catch can setup. Sorry to sound like a dumbass but I'm planing on running 10-14 psi at the track (alot more than I have been running) and I don't want to cause any MORE problems than I going to have already.

Re:what to do about pcv valve from boost
 

If I was to take the line shown here in red and just leave it loose and point it at the ground...would this setup still function the same....only with no tank?

Re:what to do about pcv valve from boost
 

no, the only mod that you could do with this setup would be to remove the blue line and install one of those small breather filters right there. If you dump the red line then the entire setup is completely useless, mise well just pull the hoses and do nothing at all.

The key here is you must have suction source which is BEFORE the turbo. Your car n/a is after the turbo on the intake manifold where you have suction until boost hits.

make sense?

Re:what to do about pcv valve from boost
 

the motor will vent the crankcase untill the pressure out side becomes postive (boost) the the pcv valve will close and the motor will stop venting the crankase until the postive pressures (boost) goes away

Re:what to do about pcv valve from boost
 

Is there any other option than the Moroso catch can?

Re:what to do about pcv valve from boost
 

I'm hoping to try this pretty soon but I would hate to see oil just get sucked right into my turbo.... I've been trying to read up on this and am reading that some people have oil squirting out of the PCV valve etc... I have no idea. But like I said I'm looking into this right now...

Anyone else have an oil catch can hooked up? If so post up what you did and how you did it?

Re:what to do about pcv valve from boost
 

that sounds right in theory, but with no air "in" on the valve cover, and the PCV vented to air, any air that happens to pressurize the crankcase will be vented out the pcv, which would have nothing acting against it. The only small problem with this is the small amount of pressure built up possibly could blow oil out the breather filter, but the PCV would still work. It opens not only on suction, but also on pressure from the backside. the reason it doesnt work being hooked up to the intake is that there is pressure working against it, but if you disconnect this line, then no pressure is against it and it will open from crankcase pressure.

I'm not saying this is the way to go, but its better than leaving the stock PCV hooked up and adding a breather filter. I didnt realize this on my own engine until after boosting for a day or so i noticed that the pressure had blown the hose from the factory catch can, so i just left it unhooked and let it vent

Re:what to do about pcv valve from boost
 

so is the moroso can thing in that diagram basically a performance/aftermarket carcoal canister? If i want to use my stock pcv valve system, can i run a line from the intake the the pcv then from the other side of the pcv to the air filter pipe and a valve cover breather and im good to go? this is assuming my pcv valve is working correctly. just to make sure, the pcv valve is the guy on top of my charcoal canister that looks like a ufo with a nipple right?

Re:what to do about pcv valve from boost
 

alright, I will come back to this again and advice some things. Having an open system really isn't good for the car.. you need a vacuum source. Keeping it stock will get you vacuum until spool time, then it's positive pressure on the motor which will end up ------- you.

No you do not have to have an expensive aftermarket catch can, I've heard of some HMT style ones and also they sell plenty of generic ones off of ebay.. might be possibly to just get the parts from a hardware store. If you just want to be cheap and not worry about it for now, just bypass the catch can and have the puprle/red lines be as one.

I don't see the confusion here, it's a pretty simple setup. Go underneath the hood of a turbo DSM and they are setup like this, not too efficient without a catch can since your intercooler/charge pipes/intake manifold just get coated with oil, lowering octane values of the fuel.

The charcoal canister is something completely different, that is for a vapor return system for "emissions" purposes. You can just disconnect that ----, plug the lines and throw it away. I may do a charcoal diagram later for you people but right now let's focus on the PCV system.

any more questions?

-ryan

Re:what to do about pcv valve from boost
 

this may sound redundant, but if the pcv is a 1 way valve, how is the boost gonna get in the crankcase?

Re:what to do about pcv valve from boost
 

the idea is that if you have 5psi of boost acting against the pcv, the crankcase will still pressurize by other means and it won't be able to vent (which is bad). dealing with the pcv is easy: just take it out. get rid of it, throw it away. replace the whole setup with a hose that goes to a vent bottle. the crankcase will be free to breathe and the oil will fall to the bottom of the bottle. You can buy one or even make your own (it's easy).

Re:what to do about pcv valve from boost
 

So basically i just connect the valve cover before the turbo and leave the PCV disconnected. This was really complicated for something so simple.

Re:what to do about pcv valve from boost
 

heres some pics of a decent priced ebay catch can i found. anyone know if this is worth it and has quality behind it?
http://www.symmicauto.com/auctions/a...2970-Front.jpg
http://www.symmicauto.com/auctions/a...ccessories.jpg

Re:what to do about pcv valve from boost
 

looks like a decent rig, whats it run you?

Re:what to do about pcv valve from boost
 

it's $35.99 "buy it now" option plus shipping which is $9.99, bringing the total to $45.98. And the best part, it's available in anodized blue, red, or polished silver. I will be purchasing one today.

Re:what to do about pcv valve from boost
 

guys.. a catch can isn't 100% required to function but the races tracks won't let you on without one. Look at stock DSM turbo cars, they don't come with catch cans. You guys are twisting the way the pcv should be setup.. here is a very simple picture:
http://www.beesandgoats.com/boostfaq/PCV_turbo_1fit.jpg

You really need to have it hooked up properly and not just unhook things and let tubes flap in the wind. The system does require a vacuum loop to it, any other way and you are looking at problems a few weeks down the road.. I know many people around here can vouch for this saying "I didn't hook it up and now my ringlands broke". Hasn't anyone here ever worked on an eclipse GST? This is the method that your 4 banger hondas run. If you had a v8 then things would be slightly different.. how hard is this to follow?

Re:what to do about pcv valve from boost
 

Alright kids this is what I do about the PVC system. The system on the back of the block is fine and doesn't need to be fucked around with. For the valve cover breather buy one of these things;

http://static.summitracing.com/globa.../mor-25900.jpg


Its a crankcase evac kit. This thing is for a V8 so there's twice as many parts as you need. But it basically uses your exhaust to pull a vaccum out of your block. V8's have been using these things for years.

Here's a basic rundown of the parts

http://www.newbieforces.com/files/mo...--tutorial.JPG

Than all you do is run a hose from your valve cover to the fitting that is now welded on the exhaust. If you have a cat weld this on after the cat. This system is simple and effective

Re:what to do about pcv valve from boost
 

how about this kit, its half the price of that one you showwed to use whitey


http://store.summitracing.com/partde...N=120%20301059

Re:what to do about pcv valve from boost
 

huh? ive never heard of this before? what do you mean, is this just for certain setups?

Re:what to do about pcv valve from boost
 

yeah that setup will work but why do you want to heat your valve cover case with exhaust gasses?

Re:what to do about pcv valve from boost
 

I guess it's early or I'm just stupid, but where does the purple line hook to. I see it says the intake pipe pre turbo, does that mean you weld or tap in a fitting?

Re:what to do about pcv valve from boost
 

So guy, what happens when the pcv valve on the exhaust closes and there is no were for the vapors to go?? Also why would you sugest to keep the stock PCV system when it was not designed for boost? This can be VERRY BAD for your rings! :-\

Re:what to do about pcv valve from boost
 

And I've also seen a couple people run two lines from there valve cover on the front to the can itself. Any difference in this set up than the others.

Re:what to do about pcv valve from boost
 

^^^^^^^^^^
Valve cover is typically for breathing, sucking air in. I don't really know why a catch can would be connected to it?

Re:what to do about pcv valve from boost
 

my valve covers alway seem to putting out air rather than in.

breathing doesnt mean to take in air, now does it?

Re:what to do about pcv valve from boost
 

It *should* be sucking air in. On a v8 one side sucks, the other blows (valve covers that is). Are you running a turbo and is it hooked up properly?

Re:what to do about pcv valve from boost
 

Whats inside the catch can ? i guessed it was empty and made my own with an old rad overfill that i had laying around , would it work correctly ?

Re:what to do about pcv valve from boost
 

most catch cans are empty cylinders but some are filled with a foam type substance I believe.. I've never bothered to take apart a high end catch can to find out :-\

Re: what to do about pcv valve from boost
 

This thread shows 2 different setups, 1 setup with the breather element, the PCV is likely always working in the high vacuum range, means low PCV recirculation all the time. While in setup 2, PCV is always working in high circulation mode, or if you are unlucky, 0 vacuum leads to blocking PCV.

Basically, it works on the difference in vacuum between intake and intake manifold. Take a minute to understand that this difference is also how people measure load of the engine. Low vacuum difference = high load (WOT), high vacuum difference = low load (TB closed). Also note that under all conditions, vacuum pre TB is always higher than post TB, it is just a matter of high or low.

Now, physics tells us that when vacuum difference between intake and manifold is high, air will take alternative path through the crank case into the intake manifold. Without the PCV, during low load, high amount of air will take another route due to high vacuum, and vice versa. This is counter intuitive because we want maximum circulation during high load.

So, PCV valve is put in to "reverse" the bahavior, as below

if vacuum is -ve : Reverse flow situation, intake manifold has higher pressure than intake, PCV blocks. (this never happens in NA anyway)
if vacuum is 0 : Engine's off, or instances where both vacuum and intake manifold are of the same pressure. The PCV blocks.
if small vacuum : High load condition, maximum PCV bypass
if high vacuum : Low load condition, small PCV bypass
if very high vacuum : PCV blocks (condition of back fire, causing temporary pressurized crankcase, PCV blocks to prevent fire from reaching the intake manifold)

As you can see, on both end of the range of vacuum, PCV blocks, and it is best to design your system such that during low->high boost/throttle, the vacuum difference works in the range of slight vacuum to some high vacuum level.

Re: what to do about pcv valve from boost
 

wow, thanks for bringing up a dead thread :P