My PCV valve has just given up and isn't holding boost anymore. I could replace it, but i wouldnt be suprised if it goes again. Consequently, my valve cover gasket has started to leak quite badly.

Has anyone here done any PCV rerouting with a turbo conversion - with a 'suck through' MAF setup? Venting to atmosphere or directing all lines prior to the turbo?

Cheers

 

I have vented to atmosphere for about 2 years on and off, depending if im tired of the blowby smell or not, right now i hooked up the pcv again. Buy a check valve to put inline with the pcv.

 

I'm thinking to block the front pcv inlet that hangs over the gearbox. Then run hoses from the two 1/2 inch PCV barbs next to the timing cover to a catch can, then a large single hose from the catch can to the pre-turbo intake pipe. I'd leave the PCV valve in there, just as a safety (to vent off any pressure)

Thoughts?

 

I installed a check valve like streetz said on the rear and the front just vents

 

Why you going to block the driver side opening for? You need as much venting as possible, while in boost the crankcase pressure is more than youd imagine.

I wouldnt do that if I were you, you dont want to be sucking from ports that dont have PCV on it, you only have one pcv valve on the car and thats the back port, the rest are just passages that are baffled inside. Without a pcv valve its going to be pulling too much and most likely end up sucking oil out (more than a catchcan will be able to handle). So my recommendation would be to run a hose from the stock pcv to a catch can then to your preturbo pipe. Leave the driver side port open with a filter. That way incase the pcv cant flow enough the crankcase would vent through the driver side port. Or you can always drill out the inlets of the PCV for more flow.

 

An interesting idea... my only concern would be that I would be sucking in unmetered air if I put a breather on the front case. I guess I could tune around it though.

 

All I have is a breather on the front case and regular pcv, I'm not sure what that would cause but mine has been like that for years. No oil leaks but I do get the blowby smell after awhile at times at idle.

 

if your pcv is hooked and u still notice a smell, then u got more blowby than what your pcv is flowing. you can drill it out to get more flow, also vac would slightly drop but can always retune ur idle

 

I've done some more research - I'm now considering doing something like this:

http://www.beesandgoats.com/boostfaq/g2icturbo.html#PCV

 

Thats how the stock setup is

 

It's a bit different, there's no PCV valve and there is two PCV outlets that connect pre-turbo - facing opposite directions to create some kind of funky flow.



Obviously the picture shows a 4 banger, but I'm thinking of swapping the pcv valve for a 15mm hose fitting.

 

Catch can time for me then.

 

on an SCed car, the rear PCV goes to teh manifold no? and that should be a problem on like 10psi correct long as its working right.

 

So I found a setup that is like stock, if you are not running a catch can then you are introducing oil into the intake. On a boosted or performance vehicle this is critical because the oil lowers the octane of the intake mixture. Doing some research my understanding is under manifold vacuum the blowby is sucked into the intake, when there is no vacuum, there is increased suction on the front valve over hose going to the stock intake, that way, no matter the situation the blowby vapors are going into the engine to be combusted. With just the little filter on the front, excessive blowby does escape but not as well as it should, plus the car starts to stink. Vacuum is needed on both covers because it is either sucking from one valve cover or the other.

The setup I had was the front valve cover hose just had the small filter on it, the problem is when the oil vapors aren't evacuated enough slight smoke and vapors would come through it, pcv valve was hooked up regular so oil was going into the intake.

The next setup I tried was after I got the catch can and turbo inlet elbow with a 3/8 port on it, I plugged the intake hose that normally puts vacuum on the pcv valve (basically a hollowed out old pcv valve was used as a fitting to run to the can so my setup was rear valve cover< hollow pcv as fitting<catch can<turbo inlet. The front valve cover hose with the filter was still putting out vapors at idle so I don't think this setup evacuated enough vapors.

The setup I currently have is I moved the pcv to the intake manifold vacuum hose <catch can< old pcv as fitting< valve cover. This way the catch can doesn't see boost. The front valve cover hose goes to the turbo inlet pipe. With this setup I noticed better engine performance. Some people run 2 catch cans, one for each valve cover which is not a bad idea because on the stock setup blowby is going into the intake both ways. the stock resonator has a chamber as a catch for blowby on it that I noticed. By no means is this gospel, I'm just saying I noticed a performance increase, and it makes sense to me if you are not allowing low octane vapors to enter the combustion chambers.

The other issue are the catch cans themselves, they are not effective if they still allow blowby into the intake, and they can if they are not baffled inside or modified to be baffled.

This thread I found has the info and pics.
http://forums.evolutionm.net/evo-how...nlet-tube.html

I won't be running 2 catch cans because there is no room, but I am going to run catch can and an air/water separator filter for the turbo inlet hose.

 

If you vent to atmosphere, I'd recommend drilling out the PCV and the restrictor on the front valve cover. It's restrictive to keep the PCV system from letting too much air past the TB at idle. The less pressure that builds up in the crank case at WOT, the more power you will make. Also keeps those valve covers from leaking.

This thread details how the Z guys do it, even though the pics are old and don't load anymore you get the idea.

http://my350z.com/forum/forced-induc...od-w-pics.html

 

I have done a good amount of testing this and in my setup I stayed with a vented system. I drilled a 1/2 hole on the front valve cover and put a barb on it, the barb then has a 1/2" hose that leads to a catch can I made which is vented, its sole purpose is to keep oil from flying to the bottom of the hood and engine bay. I also have all ports of the the valve covers open, believe it or not, even having all ports open withtout having the 1/2" hole it created pressure and caused leaks. So if your going to vent, make a new opening in addition to the existing.

 

This is great info. When I put my SC on and didn't vent the front valve cover it caused problems. I took off my front valve cover and found the spark plugs swimming in oil. I'm going to have to implement my catch can on my "new" setup.

 

Thats a big problem, because the PCV dosnt not allow enough flow to vent while in boost specially.

 

I'm thinking when the pcv is closed (partially) in boost, or not seeing vacuum the flow goes through the front valve cover hose and that's one reason it is routed to the intake in the stock setup. On a boosted vehicle we could run it to the non-charged side of the s/c or t/c intake. The spark plugs swimming in oil I don't think is a pcv or catch can issue but the spark plug valve cover seals just need to be replaced.

 

It was a stupid mistake but I replaced the spark tube seals and valve cover gaskets.

I bought a cheap catch can that I plan to use but why wouldn't you just vent it after the catch can vs routing it to the sc intake?

 

aight so maybe im an idiot and dont understand this lingo....

am i ok with the front valve cover having a breather filter on it, and the pcv valve running to the IM vacuum (stock)? i havent had any issues with it, that i know of.

 

Depending on the motor, even in part boost there is more blowby than a stock motor, so you cant use stock breather, they just dont flow enough(IF vented to atmosphere).

However routing it to the suction side of the turbo/SC is the best, because providing vacuum or near vacuum to the crank case while in boost will yield a smoother motor and more power probably, but its pretty hard to have a succesful setup like that because you will always and i mean always suck in oil. Unless you have an uber custom made aluminum catch can made.

 

Sorry if this was already posted but now it makes sense in my head but can I run this setup. Just run a check valve inline with the pvc on the rear. Then for the front run in like stock but with a check valve and catch can post turbo and maf so it doesn't see boost

 

You could, that's why they sell the catch cans with the air filters on top, you could run the hoses that usually come off both valve covers to it (block off the pcv), I'm talking about a setup like stock that uses vacuum across both hoses for the blowby. The thing about the catch cans like I said in the other post and also provided a link, the catch cans you buy that are usually inexpensive do not have any baffling, you need something to catch the oil vapors or else a bit of it still would enter the intake. The catch can with the allen screws on top are the ones you can mod. Mine was closed but I modded it anyway, I added a hose to go 3/4 of the way to the bottom of the can, you can then add some sort of media to it if possible.

I had mine running like that, I was getting fumes out of the breather filter. Also you are still allowing oil to go into the intake when under vacuum and the oil lowers the octane of the intake charge.
If the catch can is not on the inlet going to the pcv, oil is going into the intake under vacuum. You could go intake<check valve<pcv<catch can. The front valve cover hose should go before the turbo or sc. This might not be possible on every set up such as rmt you would only run the catch can going to the pcv valve and then the front valve cover could just vent. On a front feed set up and similar I had room to add an intake elbow to the turbo and it had a fitting to put a 3/8 hose on it.

 

Pretty much what maxgtr posted.
You dont wanna run the front valve cover to post turbo, the crank case needs to vent otherwise you will cause major leaks or damage something if the crankcase has too much positive pressure.

 

ok think I got it, then I'll just run the front valve cover like stock with a catch can and check on the hos going to the intake so it won't see boost but then put a 2nd breather on the can so it can still valve at boost and see vac at idle

but it seems like a vac pump would be the best way to go

 

I think you still have it confused. The one that really needs the catch can is the rear cover hose going directly into the intake manifold from the pcv valve, the front cover hose may not need one, right now I'm running a large clear fuel filter to see if any oil collects. You don't want to put a check valve on the front hose because when the pcv valve is open it sees vacuum, air is going in, when the pcv valve is closed the blowby is actually flowing out of it. That's why we say to run it to the intake side of the turbo or sc, not the compressed air side, pre-turbo or sc. A though that just occured to me is the reason the front valve cover hose is so large is because the blowby from the whole engine has to vent through it when the pcv valve is closed. A vacuum pump is the way to go if you track the car, nascar cars have belt driven vacuum pumps on them. Vacuum pumps run around $350 and up, I'm just talking about daily driving with a stock style setup.

 

I know this is an old thread but I need help.. Im supercharged and I need to add an oil catch can cause Im getting blow by from my front breather so bad it comes into the car.. I also found a nice amount of oil in my manifold when I removed my injectors for service.. So from reading through several catch can threads I think I need to add a catch can bet the PCV and back into the manifold for rear cover.. for the front cover I just have a breather there and the blow by fumes are killing me plus I'm ruining the engine bay with all that misty oil smoke..

So should the front cover have its own catch can and then go back into the intake before the blower? but how would this work under vacuum when the pcv is closed? wouldnt it still suck in unmetered air if its before the MAF? We don't want the crankcase pressurized if the front cover is run to the boost side but I don't know what else to do with the front breather.

In addition, does the PCV still need to be drilled out for more flow? or should it stay with the stock opening ? Please someone help me!!

 

This help you?: http://www.infinitifx.org/15-vq35de-...separator.html

 

hmmm what about using the Mishimoto baffled oil catch can for the front valve cover so it catches the front cover blow by oil before going into the intake before the sc/ turbo.. these are pricy catch cans but if it fixes the issue then like they say you have to pay to play.

 

It looks like from one of the diagrams on infinity.org using 2 oil catch cans and front valve going back into the intake before the SC seems to be the best and most efficient way to go.

 

Unfortunately, I don't know too much about oil catch cans. But it does sound like your PCV is clogged. When is the last time you changed it?

 

Its brand new I replaced it when I had the manifold off. I haven't driven it during the winter at all so I don't know how its gonna drive since the new PCV but I will still get blow by and will need the catch can.. also dont want anymore oil getting in my manifold.

 

Excessive blowby can also mean deteriorating piston rings. If you keep getting a bit of blowby do a compression test.

 

Yup I plan on doing a compression test a soon as I get it on the road.

My question is, if I add a catch can for the front cover wouldn't it still suck it umetered air when the PCV is open? I plan to run the catch can from the front cover and OUT of the catch can to intake side of the SC. The rear will have its own catch can. I think this is the best way to keep oil from getting everywhere, and keep the crankcase from boost pressure and better overall performance.

 

I supercharged my daily driver Max 10k miles ago. The PCV valve that I installed is already clogged up; and the TB is pretty dirty even though I cleaned that 10k miles ago as well. Time to incorporate a catch can into the system!

 

Told you man.. you probably have oil in your manifold as well.. the best thing is to use two catch cans.. that breather for the front cover will eventually get oil in the engine bay.. if it isn't now then eventually it will. It should have its own catch can from the breather front valve cover and out of the can going back into the SC supply uncharged side. This is the best way to do it from the research I've done.

Look up Sakaiou Michi catch cans.. they have the best bang for your buck for a baffled design and make custom ones for your applications.. I'm going with the dual catch can.

If you want pretty.. then the Matismoto catch cans are the most attractive IMO but prepare to spend 500 or better for two catch cans. And they don't have custom designs.

 

What's weird is that the PCV valve on my beast CF Max has never clogged, but on my daily, it clogged really fast! None of my SC'd Maximas have the smoking problem you mentioned earlier. All breather filters on the front valve covers aren't clogged or dirty either.

Yeah, I knew I'd have oil residue in the manifold, that's normal w/o catch cans.

I remember asking meximax about catch cans years ago, and all I can remember is that he said that the route of the catch can system on a SC'd car is different than a NA car. I don't recall ever getting specific details unfortunately.

I'm still confused on all the routing of the lines. I'm sure it's really simple, it just hasn't sunk in yet.

 

It took me a while to understand how to run the lines as well. See post 29 and post by Streetzlegends, Maxgtr2000, and T6378tp.. they really help and clear things up. But as I said go with two catch cans cause oil will get into the manifold via the PCV and also you will get that misty white smoke and oil out of the front Valve cover.

 

The front vent is active when there is not much vacuum (more flow output and a larger hose), the rear vent is active during vacuum(has a smaller hose because of less output. The valve covers are connected together on the timing cover side by a hose.

You actually get most oil in the intake during idle because there is no catch. The factory midpipe has a catch but not really much oil droplets get through there like on the pcv valve side, so just putting a filter on the front valve is fine, the rear is the one we should worry about.

For boost I looked at pictures of how turboed supras are set up. The larger hose (front valve cover) goes to the turbo/sc inlet. You would have to use an adapter or special pipe. I ran a catch to intercept the pcv side and used this type of inlet on the turbo intake side. It's not the same exact one but you get the idea. You can make one with a fitting and silicone elbow, but it is not that important unless you get a bit of blow by. The one on the rear is what keeps the intake manifold clean.