If you run an MAF and you want crankcase vacuum, you must have a *closed loop* system. You can't use the breathers. This is the most important to remember.

Now, if you do not want crankcase vacuum, you could use a catch can and the breathers. But then it's almost pointless to have a can. You could... a friend of mine has all the ports capped off and uses a can (on his z06 valley cover tube) to catch some of the blow by gas. But it certainly doesn't catch the kind of oil a pressurized system can.

 

if you are to do an MMS setup you will need to follow the diagram included with it.

mixing and matching different cans and connection strategies can lead directly to trouble and frustration

 

So a Closed Loop System would be

1. Hose from Silver TB port to 1 of the driver side VC ports.
2. Hose from other Driver Side VC port to Passenger VC port.
3. Hose from LS6 Valley cover to non vented Catch Can
4. Hose from Catch Can to Port on intake
5. Ditch the breather as oil fill and get regular oil cap

and that should have me maintain PCV but not building up to much Crank case pressure?

EDIT:

Would simply running a hose from TB to Passenger VC and capping the driver side port as well as the second passenger side port yeild the same results as just running a hose between the DS port and 2nd PS port? Or would the lack of air traveling between both VCs cause an issue?

 

I found this company, but can't get anyone to respond to my questions on details. The owner has an answering service..... but, still doesn't help.....
Looks like a nice system, tho....
https://www.rxspeedworks.com/

 

happy to help..

mightymouse solutions answers emails and phones alllll day.

they also have instructions with their catch cans you can follow for confidence and success vs. all this guess work and uncertainty!

 

That all sounds correct.

FWIW, my stock LS6 system has the driver side valve cover ports capped. The port coming from the throttle body is the "clean" side that pulls in fresh metered air from the inlet tube and brings it through the valve cover and then is drawn out through the valey cover port. Leaving both sides of the valve covers connected shouldn't have any ill effects, though.

 

Mighty Mouse;
I have a 383, 4" crank, heads, cam and I am running a Vic Jr with a 92mm FBW TB and an LS6 Valley cover.
I have 3 oil vents on this set up. Passenger side, valley cover and Drivers side PCV.
Currently I have routed the PS & VC in to a TEE then connected that with the DS PCV (with a tee) to a Mike Norris catch can and then routed back into the intake.

Do you see a problem with that?
Thanks!

Chad

 

If you have vents AND a PCV, you effectively have a large vacuum leak. You are letting in unmetered air that is drawn in through the PCV system.

 

A vacuum leak, doesn't the passenger side vent tube (on the valve cover) go to the filtered side (down stream) of the air cleaner on a regular truck TB? Mine did.
Doesn't the LS6 valley cover vent tube essentially take the place of the PCV and it gets ran to the catch can?
The PCV line on the driver side valve cover was routed (prior to the new intake) per Mike Norris instructions, to the top of the catch can, as it is now with the new intake..
Should I just cap off the passenger and drivers side vent line's and just use the LS6 valley cover vent line?
I don't see a vacuum leak, help me understand what your saying. Thanks for the help!

Chad

 

Of your 3 "vents", are any open to atmosphere...?

Where is your fresh air inlet...?

 

Answers in bold.

This thread has further diagrams of how PCVs are routed:
https://ls1tech.com/forums/generatio...fo-needed.html

 

No, all three lines/connections (1.driver side PCV connection 2.passenger side connection, 3.LS6 Valley Cover connection) all go to the catch can.

I guess I don't have a 'fresh air' inlet. As I stated, all three connections go to the catch can and then one line from the catch can goes back to the intake.

Chad

 

I'm sorry, I was under the impression that by "Vent" you had one of those open element filters on the valve covers while also having the PCV connected.

 

That link show almost exactly what I have, thanks! I still have a couple of questions about it. The first picture from that link is what I am talking about, it shows what I have as far as connections. PCV, Valley Cover & Passenger Side connection.

On this diagram it shows my driver side PCV and my LS6 Valley Cover coming together with a TEE and then to the Catch can and then out into the intake. I got that!
It also shows the passenger side connection going to the side of the Throttle body, I don't have that. My electronic throttle body which is a 92MM Gold Blade, does not have that connection. My Edelbrock elbow doesn't have that connection either. The Edelbrock Vic Jr intake has a port (threaded hole) in the side of the intake that I am using as the return line from the Catch Can.
Do I need to make a connection somewhere from the Passenger side connection to the intake somewhere or just cap it off?

Chad

 

No worries bro, thanks for the help! Its hard to put down into words sometimes what I am trying to explain. I appreciate the help and your response, that's what this forum is all about!



Chad

 

So you're saying you don't have an air inlet for the PCV?

The threaded hole in the intake for the return line sounds correct, but it sounds like it's just putting the system in slight vacuum without clearing/refreshing the air. Vacuum isn't a bad thing, and actually provides some benefit, but the other objective of clearing blowby and contaminated vapors from the crank case isn't happening like it should.

Is your TB more like the one on the left or right?




Here's an example of where the air is drawn for the valve cover (rocker cover) on a typical TB

 

yes i see a problem.

to run a pcv system, the final leg to the intake manifold must include only one line and that line must include the pcv valve or orifice to control the vacuum exposure to the crankcase.

you cannot Tee an unrestricted port in with the pcv port/valve. the air will take the path of least restriction, and the pcv valve will lose control of the system.

all of the MMS cans for PCV systems have a one-way pressure release top to control crank pressure without upsetting pcv closed loop function, or the tune.

 

On the left

Chad

 

i posted this in this thread already, reply #625

if you have a throttle body without the fresh air port then you need to add one to also match how the newer cars with these ports do it. after the maf and in front of the tb blade.



some that make aftermarket couplers have a port molded into them as well.



what is very important to NOT DO in general, is to delete something just because you don't understand it. thats a quick way to get yourself into trouble. research it. understand it, then decide what to do.

 

There is only one (1) line going to the intake from the catch can.

Chad