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Let's Talk Pcv...

Tony de Wonderful
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rob82 Mentor

rob82

Posted
Posted

It's no different that the stock set up in that regard though.

If your venting the catch can then you will have air entering the engine the engine that is unmetered.

Best solution when removing PCV is to run both rocker cover breathers to a sealed catch can and then a single line back to the inlet pipe.

rob82 Mentor

rob82

Posted
Posted

That's what I thought but it looks like It's creating enough pressure to blow the front seal?

IF you've pumped the head full of oil then the there is no path for the blowby to release pressure from the sump - usually this is when dipstick pops. Not sure why your front seal is failing though. How hard is it to remove your dipstik?

Anyway the fix will most likely reduce the amount of oil in the head - ie smaller restrictors.

ARTZ Grand Master

ARTZ

Posted
Posted

Best solution when removing PCV is to run both rocker cover breathers to a sealed catch can and then a single line back to the inlet pipe.

That is the best setup when keeping the PCV...

If removing the PCV best to vent atmo...

Birth Experienced

Birth

Posted
Posted

I wouldnt say that the dipstick is stuck or hard to remove at all.

I don't really care about keeping the PVC or not - I just thought it would be better if I removed it.

Is there any benefit to keeping the PVC and most of the hoses from the factory, but install the catch can beetween the exhaust-side rocker cover and the inlet before he turbo?

I guess the immediate other option would be to remove it altogether?

Birth Experienced

Birth

Posted
Posted

I wouldnt say that the dipstick is stuck or hard to remove at all.

I don't really care about keeping the PVC or not - I just thought it would be better if I removed it.

Is there any benefit to keeping the PVC and most of the hoses from the factory, but install the catch can beetween the exhaust-side rocker cover and the inlet before he turbo?

I guess the immediate other option would be to remove it altogether?

Tony de Wonderful Veteran

Tony de Wonderful

Posted
  • Author
Posted

If your venting the catch can then you will have air entering the engine the engine that is unmetered.

Er if the catch can is venting to atmo then it is venting to atmo and not the intake!

Best solution when removing PCV is to run both rocker cover breathers to a sealed catch can and then a single line back to the inlet pipe.

That is the set up which is being criticised for sending unmetered air into the engine. I was saying that it does the same thing as the OEM set up except the PCV on the intake cam cover in blocked and the oil drops out in the can. If it send umetered air into the intake then so does the OEM set up!

Tony de Wonderful Veteran

Tony de Wonderful

Posted
  • Author
Posted

Is there any benefit to keeping the PVC and most of the hoses from the factory, but install the catch can beetween the exhaust-side rocker cover and the inlet before he turbo?

Well you still get oily air being sucked in off boost so it is kind of half-arsed solution.

Hanaldo Grand Master

Hanaldo

Posted
Posted

Er if the catch can is venting to atmo then it is venting to atmo and not the intake!

That is the set up which is being criticised for sending unmetered air into the engine. I was saying that it does the same thing as the OEM set up except the PCV on the intake cam cover in blocked and the oil drops out in the can. If it send umetered air into the intake then so does the OEM set up!

What? If the catch can is plumbed back into the intake AND venting to atmosphere then you will be drawing unmetered air in through the vent and into the system. If everything is plumbed in, you can't get any unmetered air going in. Where do you think this air is coming from??

Tony de Wonderful Veteran

Tony de Wonderful

Posted
  • Author
Posted

What? If the catch can is plumbed back into the intake AND venting to atmosphere then you will be drawing unmetered air in through the vent and into the system. If everything is plumbed in, you can't get any unmetered air going in. Where do you think this air is coming from??

Where was I advocating venting to air AND plumbing back into the intake?

Maybe I got this wrong but the solution where you block the PCV valve then keep the other side plumbed into the intake via a catch can (which is closed), was criticised as allowing unmetered air into the system and someone said you have to just let the catch can vent to atmo or it screws everything up? Can't be arsed going over the thread to find what was said.

Birth Experienced

Birth

Posted
Posted

See, I was thinking thy the sucking pressure that the PVC gives off-boost would be offset by the draw from the turbo (not necessarily pressurized) when plumbed back before the turbo.

I have seen pictures above which keep the PVC by having a t-piece near the PVC with one side going to the rocket cover and the other going to the catch can. I am guessing that this would be inefficient as the PVC valve would draw some air from the can rather than drawing all it's air (and vapor from the rocker cover)?

Hanaldo Grand Master

Hanaldo

Posted
Posted

Where was I advocating venting to air AND plumbing back into the intake?

Maybe I got this wrong but the solution where you block the PCV valve then keep the other side plumbed into the intake via a catch can (which is closed), was criticised as allowing unmetered air into the system and someone said you have to just let the catch can vent to atmo or it screws everything up? Can't be arsed going over the thread to find what was said.

You didn't, someone else did.

I don't understand where you think this air is coming from? The stock setup is a sealed system. There is no unmetered air in the system.

JonnoHR31 Grand Master

JonnoHR31

Posted
Posted

See, I was thinking thy the sucking pressure that the PVC gives off-boost would be offset by the draw from the turbo (not necessarily pressurized) when plumbed back before the turbo.

nope, at idle the intake pipe has very little suction, if you put a gauge on it you probably wouldnt get any vacuum, whereas the plenum has heaps due to the throttle body being shut. obviously the closer you get to 0 vacuum in the plenum the less it would draw through from the intake side, until the pcv shuts as soon as you hit boost then it starts flowing the other way if theres any blowby.

@hanaldo, he doesnt think theres any unmetered air coming in, someone else implied that and has confused you :thumbsup:

BMYHOE Proficient

BMYHOE

Posted
Posted

has anyone noticed on the exhaust side of the head (RB25-RB26)

there is a threaded plug that can also be used asa drain back to the sump similar to the rear head drain.

depending the what exhaust manifold you have on there it may of may not be accesible. on my 2530 there is plenty of room to do this. just need to get around to finally doing it.

Dasmbo Collaborator

Dasmbo

Posted
Posted

Hi this is how mine is setup works great large hoses from r/covers and smaller hose to turbo inlet catch can full of coarse stainless steel wool and pvc stock

Back to what i believe was part of the original question and what i would like to know, is it better to use bigger breather hoses to get more out faster than standard, i have mine plumbed up in the factory configuration but i use a line from the cam cover that does not have a restrictor in it like the factory line does, it then runs through a catch can filled with stainless steel wool as a filter and then back to the intake pipe, is this better/worse/no different to have the restrictor in the line?

post-58211-0-11078900-1326805232_thumb.jpg

gotRICE? Veteran

gotRICE?

Posted
Posted

I used to have my breathers vented to Atmo with the PCV blocked but after a while i was getting blowby and plumes of smoke out the exhaust at idle, and taking off, and backing off.

I was advised to put the PCV back to stock, and have never seen another cloud of smoke since.

The setup i have now is, Stock PCV, Breathers vented to Atmo VIA a catch can, and no turbo inlet pipe.

DSCF0964.jpg

As someone mentioned, i just dont think the turbo inlet has enough vacuum at idle to sufficiently draw the vapours out of the head, if it did then the PCV wouldnt be there factory.

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