Help Me Vent

[LS1ow]

Time to get my catch can routing done. I read up on some stuff, but it seems no body has the same set up as me. And im hoping we can figure something out without having to make any major changes.

First i didnt think there was this many openings, but man, these is a ton of ports lol

Pass Valve Cover
-1 nipple at rear of the cover, has a small breather filter on it.


Driver Valve Cover
-2 ports at the top near the injectors; Breather filter in place of oil fill cap.



LS6 Valley
- 1 port in the front

Throttle Body
-1 Port

Intake Manifold
-1 port off the driver side near TB
-1 port off the pass side near TB
-1 port of the rear under MAP sensor

Valley Cover, TB and Pass Intake port:


Rear Intake Port:


Driver side intake port:


Im just going to assume the port on the rear of the intake is the port for the check valve line that goes to the booster.

What i have in my mind is:

-"Loop" both driver side ports with a hose
-Cap the driveside port by the TB
-Cap the TB port
-Run the hose from LS6 Cover, To catch can, then to passenger port near TB on intake.



Thoughts & Revisions?

[wretched73]

Sounds about right but i think you have more ports than my truck intake so its hard for me to say for sure

I go from Drivers side valve cover to catch can to port on top of intake

[Blackbirdws6]

The "simple" way I always think about it is to have the VC breather act as the fresh air port, a line on the opposite VC will go to the inlet of the CC with the exit into the intake mani.

[wretched73]

Originally Posted by Blackbirdws6

The "simple" way I always think about it is to have the VC breather act as the fresh air port, a line on the opposite VC will go to the inlet of the CC with the exit into the intake mani.

What do you mean a fresh air port? In reality, because he has breathers on both of his VCs, he wouldn't need a catch can at all and could cap all the ports. The breathers should just allow blowby to exit. Same as any ole SBC

[Blackbirdws6]

Originally Posted by wretched73

What do you mean a fresh air port? In reality, because he has breathers on both of his VCs, he wouldn't need a catch can at all and could cap all the ports. The breathers should just allow blowby to exit. Same as any ole SBC

You want air to be pulled through the system. I would just run one breather and the other with an oil fill cap. This is how I have my setup configured with the only difference being a check-valve on the line to the intake (avoid boost reversion).

[wretched73]

But air shouldn't have to be pulled through the system, the vents are just vents so pressure doesn't build and push out a seal

[Blackbirdws6]

Originally Posted by wretched73

But air shouldn't have to be pulled through the system, the vents are just vents so pressure doesn't build and push out a seal

How will the dirty air travel through the can if you are just venting? In the way I described, the engine will pull air through it under non-WOT conditions (vacuum). If he is concerned with just avoiding oil in the intake and crankcase pressure, run a couple breathers and call it a day.

[wretched73]

Oh ok, i think we're just not understanding each other. I get that air has to be pulled through the catch can, i thought you were saying the VC had to allow air to flow into the engine- which confused me.

[LS1ow]

I really dont want to ditch the Oil fill Breather... bc swag.

Id be fine ditching the passenger side breather and capping that off. If i did that, then i can just cap both ports at the top of the passenger VC, use the oil fill vent filter as the "inlet" and then run a hose from LS6 Valley, to CC, to Intake manifold??

And block off the TB and driverside port as well.

[LTb1ow]

Mine is setup similarly to BLS.

One VC is a breather, and the other goes to catch can. Catch can has a vac source prior to turbo and will vent if pressurized in engine. But, in theory its always gonna have vacuum pulling clean air through the crankcase and venting out fumes.

Don't over think it.

[Blackbirdws6]

Originally Posted by LS1ow

I really dont want to ditch the Oil fill Breather... bc swag.

Id be fine ditching the passenger side breather and capping that off. If i did that, then i can just cap both ports at the top of the passenger VC, use the oil fill vent filter as the "inlet" and then run a hose from LS6 Valley, to CC, to Intake manifold??

And block off the TB and driverside port as well.

Just make sure the port for the can inlet is on the opposite side of the engine where the breather resides.

[LS1ow]

Originally Posted by Blackbirdws6

Just make sure the port for the can inlet is on the opposite side of the engine where the breather resides.

im screwed then. Bc the Breather is on the passenger Valve Cover, All the catch cans sit on the passenger side. So the fresh air would come in threw the oil fill breather, exit the engine threw the Valley cover, into the CC and then from CC dump into the intake manifold after the TB.

[Blackbirdws6]

Originally Posted by LS1ow

im screwed then. Bc the Breather is on the passenger Valve Cover, All the catch cans sit on the passenger side. So the fresh air would come in threw the oil fill breather, exit the engine threw the Valley cover, into the CC and then from CC dump into the intake manifold after the TB.

Just run a line....

[LS1ow]

Either im missing something or im just a doofus.

Run line meaning what? To run the CC on the driver side?

Or run a line from the Passenger VC to the CC? If so, what about the LS6 Valley Cover?


halp.

[sweetbmxrider]

What is confusing?

[LS1ow]

Originally Posted by sweetbmxrider

What is confusing?

MM website shows Oil fill adapter as both a vent style filter like i have, but also like this.

[The_Bishop]

Do you have the LS6 valley cover? If so that's got the breather system where it should be pulling air from the valley.

[LS1ow]

Originally Posted by The_Bishop

Do you have the LS6 valley cover? If so that's got the breather system where it should be pulling air from the valley.

Yaaas

[LS1ow]

This dude laid some knowledge on me...

what is your use for this engine? Race only? Do you want positive crankcase ventilation (ie vacuum applied) like a street car? Are you in a state where this car needs to pass an emissions check?

If I read your plan right, I think it's going to cause huge problems.

The port on the throttle body itself is for clean air to go into the crankcase. I consider it "high pressure" for simplicity sake (but that's not actually true, it just makes it easy to think about).

You have breather filters on both valve covers and those are going to release crankcase pressure right out to the engine bay/atmosphere. They will also allow air in if there is a vacuum applied, and this will be a problem also. If you want PCV, you'll have to put solid caps on these positions or do something else, see below.

For PCV, you need a "closed" system. Air can not escape out of the crankcase on it own. Some clean air from the thottle body goes into the crank case and then the intake manifold vacuum draws the same amount back out, so the MAF does not lose or gain any air from unmetered sources.

What you proposed (I think) seems to maybe pull some crankcase air, but because of the valve cover breathers, you'll be pulling outside air into the engine, and into the intake manifold, but the MAF hasn't seen it. It's like a huge intake vacuum leak, or running at WOT even with the throttle close.

If you don't want PCV, you can leave the breathers, and also put caps on all the other locations too, and you're done. You don't need a can.

If you do want PCV, I'd suggest:
-Run a hose from silver thottle body tube to one of the barbs on the driver side valve cover. This "clean air" supply will push air into the crankcase. (Not really push, but for simplicity sake)
-Run a hose from the other driver side valve cover hose to the passenger side valve cover. Remove the breather and get an L fitting thing to stick into the hole like stock engines have. This also allows some air to circulate to the passenger valve side.
-Run a hose from the LS6 valley cover tube to the "intake" side of your catch can. The LS6 valley cover has its own oil separator built in and will help remove some oil from the air. Do not use this as an air input area.
-Run a hose from the catch can "output" to one of the ports on the intake manifold right behind the throttle body. This is your vacuum source which "pulls" air out of the crankcase, through the can.
-Put a plug on the other intake manifold port behind the throttle body. Stock LS1/6 manifolds only have 1 port, yours has 2 for some reason.
-Remove the breather filter from the driver side oil fill hole and put a normal oil cap that seals all the way.
-Put brake booster hose on back of intake manifold.

[sweetbmxrider]

That's what I was thinkin....

[LS1ow]

sigh.... but the breathers look so cool !

[LTb1ow]

Right, forgot I run SD.

You could do the same, race car speed density tooone that bitch!

[Blackbirdws6]

I'm just here to extend the thread.

[LS1ow]

so looks like ill be ditching my breathers

[MyFirstZ]

Passenger side will be hidden anyway