Breather

**tingo99** · 07-22-2008, 06:57 PM

i just got this from a friend for free do i just screw it in where the oil cap goes?

http://www.pfyc.com/pc/GN3020/GNUNDE...S1%2C+LS6.html

**tingo99** · 07-22-2008, 07:20 PM

ok yea dumb question it doest replace the oil cap but i have a strut tower brace so it doesnt fit can i take that plastic piece off that the original oil cap goes on and scew this new breather directly on the calve cover?

**mark21742** · 07-22-2008, 11:38 PM

Originally Posted by tingo99

ok yea dumb question it doest replace the oil cap but i have a strut tower brace so it doesnt fit can i take that plastic piece off that the original oil cap goes on and scew this new breather directly on the calve cover?

channel locks with some pressure give the oil tube a twist counter clockwise, should pop right off. then mount your new breater riht on the valve cover

**tingo99** · 07-23-2008, 01:57 PM

cool thanks

**Sarge** · 07-23-2008, 02:33 PM

This may interest you....
http://www.ls1.com/forums/showthread...light=breather

**tingo99** · 07-23-2008, 05:27 PM

good info!

**Wesman** · 07-23-2008, 06:46 PM

Originally Posted by Sarge

This may interest you....
http://www.ls1.com/forums/showthread...light=breather

Just read through the thread.

Currently I just run breather filters on my valve covers, PCV is deleted and vacuum ports are capped off.

Maybe I'm missing something here, but if you're running open breathers on the valve covers and have a hose running to the PCV port on the throttle body, will that not create a vacuum leak/lean condition?? Basically you are pulling in outside air through the breather filters and inducting it after the mass air flow sensor, so therefore it is pirated incoming air that is not accounted for. If the valve covers didn't have breathers on them (like stock), the system would be mostly sealed and you would only be inducting crankcase vapors that make it past the rings in the form of blow by, not any outside air.

Let me know if that makes sense to you.

**Sarge** · 07-24-2008, 11:55 AM

Are you talking about the catch can? Your running from the valley tray through the catch can back into the throttle body versus from the valley straight to the throttle body. I run a SD tune. I have no MAF.

**Wesman** · 07-24-2008, 07:00 PM

Originally Posted by Sarge

Are you talking about the catch can? Your running from the valley tray through the catch can back into the throttle body versus from the valley straight to the throttle body. I run a SD tune. I have no MAF.

I understand that part...but being that you have breathers on the valve covers that aren't there stock, won't the system be drawing in air from the outside (thru the breathers), passing it through the engine (along with crankcase vapors), and then sucking it into the intake manifold after the throttle body?? Seems like pirated air to me, since in stock form only crankcase vapors would be drawn in being that there is no direct path to an outside air source via breather filters. Catch can or no catch can, it would still be the same issue.

**Orcus79** · 07-24-2008, 08:15 PM

All the PCV system does is balance pressure betwene the block and out side. Under vacuum the vapors are drawn into the intake and under positive pressure that system is blocked (PCV valve).

You are probably correct in guessing that running both a PVC and breather could cause a vaccuum leak type senario. but I some how doubt it as the PCV can only flow so much volume based on what the intake pressure is.

**Sarge** · 07-25-2008, 02:18 AM

OK I see what your saying....no...the PCV just balances the pressure.....we have too much pressure in the LSX engines and the breathers reduce that pressure/resistance in the crank...the breathers blow air out more than suck it in....Lil blurb from GM....

Originally Posted by -GMHighTech

The LS-Series engines are prone to excessive crank case pressure build-up resulting in oil blow-by, oil consumption, and oil wetting of the intake manifold. One of the first changes from GM to help resolve this issue was the bay-to-bay “windows” placed in the main webs of the blocks. Any increase in cubic inches places more demand on the PCV system, regardless of the engine type. GM has made several changes to the PCV systems over the years and many consumers have a mismatch of parts and components. It is imperative that you inspect your PCV system and make certain that it functions properly. If you are using a factory PCV system it is required that you use a new “fixed orifice” PCV valve for routing your pressure relief hose from the valve cover. This valve is included with all custom XXXX LS-Series short blocks and engines. The GM part number for this item is #12572717.

**Wesman** · 07-26-2008, 08:21 PM

Originally Posted by Sarge

OK I see what your saying....no...the PCV just balances the pressure.....we have too much pressure in the LSX engines and the breathers reduce that pressure/resistance in the crank...the breathers blow air out more than suck it in....Lil blurb from GM....

Ok that makes sense then, glad you see where I was coming from though