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-   -   PCV goes to fresh air (https://www.cobaltss.net/forums/2-0l-lnf-performance-tech-153/pcv-goes-fresh-air-321287/)

blueLNFftw 04-08-2016 03:05 PM

PCV goes to fresh air
 
Are there any issues with venting both of the PCV lines on my valve cover to fresh air?

ECaulk 04-08-2016 03:14 PM

If you're using a vacuum pump it should be ok, otherwise there will be no vacuum on the valve cover to extract the vapor. I'm also going from memory of the pcv system right now

blueLNFftw 04-08-2016 04:01 PM

Their isn't enough crank case pressure to push out without vac?

Kolt 04-08-2016 04:23 PM

yes there is but you don't want positive pressure in the crankcase, it will *eventually* cause oil seals to blow out, the pcv system is designed to work under a very mild vacuum.

also the mild vacuum helps keep fuel vapors from condensing and also helps fuel that has already condensed into the oil to evaporate.

exninja 04-08-2016 04:29 PM

The info I got from John Powell says "If you vent the pcv to atmosphere with a filter like a hot rod vent cap, all bets are off and the pcv system will not work at all as intended." In it, he alludes to the fact that the orifice depends on slight vacuum to function correctly, but that's all I can infer from it.

blueLNFftw 04-08-2016 04:30 PM

I know the pressure is bad.

My thought is that there is enough pressure to push out the vapors.

I just don't know if I am on the right path. Long ago engine just had a dump. It's my understanding the only reason this no longer continues is because of emissions.

Kolt 04-08-2016 04:40 PM

See my first post...

also venting to atmosphere will cause a very slight lean condition at times due to the pcv system is a orifice type located in the head. under normal(no boost) operation the intake manifold vacuum sucks on the crankcase through the orfice and fresh filtered (and measured air) comes in through the valve cover. While under boost though the pcv orifice is at a size to limit putting boost pressure into the crankcase, at this point your inlet side of the turbo serves as the vacuum point to pull crankcase pressure and vapors back into the intake.

blueLNFftw 04-08-2016 06:47 PM

Okay. I understand now; I won't do this.

My thought process was to just vent to atmosphere instead of tapping the intake for the s20g turbo.

I'll just go search eBay for the fittings I need to hook up the PCV lines the way they were intended.

Sl0wbaltSS 04-08-2016 09:22 PM

On the LNF I thought the PCV went to the turbo? SO if the nipple on the stock airbox commonly broke off it would cause it to run lean cause the turbo was sucking in air from that pcv that goes to the valve cover, then through the other hose to the intake?

tomj77 04-09-2016 01:07 PM

get a powell oil separator 3.0 and call It a day

ItalianJoe1 04-09-2016 01:33 PM

The stock system is designed with one inlet and one outlet. It pulls in clean, filtered, post-MAF air from the intake. It feeds it through the engine to pull out combustion bypass gasses and evaporated water in the air in the crankcase area. It pulls it into the engine and burns it so it's not dumped outside as emissions.

If you open the inlet and remove the vacuum source, there is no way the system can work as designed.

blueLNFftw 04-09-2016 03:38 PM


Originally Posted by ItalianJoe1 (Post 7602798)
The stock system is designed with one inlet and one outlet. It pulls in clean, filtered, post-MAF air from the intake. It feeds it through the engine to pull out combustion bypass gasses and evaporated water in the air in the crankcase area. It pulls it into the engine and burns it so it's not dumped outside as emissions. If you open the inlet and remove the vacuum source, there is no way the system can work as designed.

What about the outlast?

The line that connect to the turbo

tomj77 04-09-2016 03:47 PM


Originally Posted by blueLNFftw (Post 7602806)
What about the outlast?

The line that connect to the turbo

U will get oil buildup from outlet that will gunk ur intake valves and u will eventually need to walnut blast Em. Like I said, get Powell oil seperator 3.0 and eliminate all the worries and ill be good to go

exninja 04-10-2016 12:31 AM


Originally Posted by blueLNFftw (Post 7602806)
What about the outlast?

The line that connect to the turbo

Kolt is correct.

ItalianJoe1 04-10-2016 02:57 PM


Originally Posted by blueLNFftw (Post 7602806)
What about the outlast?

The line that connect to the turbo

The line that connects to the turbo is the vacuum source, it pulls the gases out of the engine. You should add a separator in the system like powell does if you are concerned about blowby contamination, but the system should be left in working order.

Kolt 04-11-2016 09:14 AM

The best approach is to do what tomj77 said and install a oil separator to take out any oil droplets so that they don't collect on the intake valves.

blueLNFftw 04-11-2016 09:15 AM

I was more looking at it because my new turbo will not have the connections for it.
I will have to get bungs and make some though.

Who was it that figured out what seperator Powell used? I know it was posted and I saved it, but I cannot find it now.

Kolt 04-11-2016 09:19 AM

the oil separator goes between the turbo and the valve cover. if the turbo your gonna use doesn't have a fitting then just get a intake tube that does after the maf sensor.

blueLNFftw 04-11-2016 09:36 AM


Originally Posted by Kolt (Post 7603092)
the oil separator goes between the turbo and the valve cover. if the turbo your gonna use doesn't have a fitting then just get a intake tube that does after the maf sensor.

Would the MAF sensor hole be close enough to work?

My MAF is relocated so I just have a plate there. I could make an adapter out of an old MAF plate to utilize that hole.
I would prefer to do this over drilling a hole in the intake.

Kolt 04-11-2016 10:29 AM

Maybe? the closer to the turbo the better but it probably would work.

blueLNFftw 04-11-2016 10:31 AM

I think I will try it out.

ECaulk 04-11-2016 10:42 AM


Originally Posted by blueLNFftw (Post 7603089)
I was more looking at it because my new turbo will not have the connections for it.
I will have to get bungs and make some though.

Who was it that figured out what seperator Powell used? I know it was posted and I saved it, but I cannot find it now.

It's a Mann, but honestly it's just as expensive to buy it from someone other than Powell, and with buying from Powell he'll send you the dip stick with the return, all the lines, and a mounting bracket.

tomj77 04-11-2016 01:13 PM

U also can go with the 2.0 system, the 3.0 addresses the pcv in the manifold and totally else illiminates any oil from getting on the valves, the 2.0 system is cheaper cause it just addresses the crank vent port. 3.0 system u get a new modified intake manifold

blueLNFftw 04-11-2016 01:36 PM

I cant do the 3.0 then; I have a shaved IM that eliminates EVAP and a bunch of other stuff.

sev 04-11-2016 02:26 PM

1 Attachment(s)
What issues will this cause.

Looking for how to setup the pcv system on these motors yields a bunch of methods that apparently are mostly all wrong.

Attachment 11970


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