LSx crank case ventilation best practice

[P10crew]

I'd like to get some LSx crankcase ventilation best practice discussion going here.
Many options available and I see all different iterations being used.
Valve covers -pcv- intake
Valve covers- pcv - catch can - intake
Valley pan
Vacuum pump and on and on
What works best and why?
Slowly gathering parts for my next project which is a supercharged LQ which will have to run wider ring gaps and have considerably more crank case air flow. I'm not real keen on burning the oil that was scavaged from the crank case for obvious reasons but not real sure that just venting a catch tank is best practice either.
Any thoughts?

 

[Brian123]

Vacuum Pump will work from what I have read if you are hitting high rpm's.

Catch Cans are good if you are hitting high rpm's.

 

[P10crew]

And one question that I have never found an answer to is which area of the motor has the least amount of suspended oil. Valley area or valve covers?

Gen 4's had venting in the valley which I have to assume was an attempt to scavage less oil. Did that system work better than in the valve covers?

The super charger that I have is a Magnason and I don't think any of the valley plate surface is exposed enough to install a breather fitting.

 

[clinebarger]

This what I do on Magnuson supercharged LSx engines. High capacity venting/breathing ability at WOT/Maximum Boost is the most important in my opinion.
Weld in some -12 fittings in both valve covers & run some 2000 series Fragola "Pro-Flow" fittings & hose to a high capacity Moroso 85469 breather tank.


As Magnuson & Whipple chargers have low pressure/manifold vacuum area directly behind the throttle body.....You don't need a check valve in the PCV plumbing like on a Turbo or Centrifugal supercharger set-up. You don't have to use the Moroso catch can in particular....But I do recommend a catch can of some sort, Elite Engineering has some nice albeit expensive ones.

With the fresh air return open to the atmosphere....Running a "Speed Density" tune is probably best.

I've seen many valve cover installed breather setups.....They make a MESS, Especially on boosted applications. I like the Valley Cover PCV location & it has a separator of it's own. The picture below is a LS2/LS3 cover.....LS6 is similar.

 

[clinebarger]

Originally Posted by P10crew
And one question that I have never found an answer to is which area of the motor has the least amount of suspended oil. Valley area or valve covers?

Gen 4's had venting in the valley which I have to assume was an attempt to scavage less oil. Did that system work better than in the valve covers?

The super charger that I have is a Magnason and I don't think any of the valley plate surface is exposed enough to install a breather fitting.


I took to long to post

, The LS6 valley cover fits Gen 3 engines. But some Magnuson chargers don't allow use of it (Most notably the Holden/GTO kits)

The PCV is best at the Valley Cover.....Fresh Air Return/WOT Breathing is best done at both valve covers.

 

[Olas]

Moroso 25900 on each valve cover.

https://www.jegs.com/i/Moroso/710/25900/10002/-1

 

[AZjeff]

*

 

[P10crew]

Thanks CLine.
No check valves in both systems as drawn correct? I


Olas we used to run those on the drag cars back in the seventies. I don't think the O2 sensors would be happy though

 

[clinebarger]

Originally Posted by P10crew
Thanks CLine.
No check valves in both systems as drawn correct? I



No check valve.....Check valve is only needed if the PCV ever sees boost which isn't the case with Magnuson Blowers.

 

[P10crew]

CLine ... I'm not the tuner of the family. Can you expound on the speed density tune? What all data and calculations go into a speed density tune? My son is liscenced with HP tuners and is swamped with work. Any head start that I can get to save him time will be greatly appreciated.

 

[AZjeff]

Curious what this engine is going in and the intended use?

 

[Olas]

Originally Posted by P10crew



Olas we used to run those on the drag cars back in the seventies. I don't think the O2 sensors would be happy though



Depends on placement though - move the 02 forward or locate the nipple rearward of the factory 02 location. nobody is suggesting you go upstream and poision your 02, that would be counterproductive.
KISS! keep it....super simple? haha!

 

[clinebarger]

Originally Posted by P10crew
CLine ... I'm not the tuner of the family. Can you expound on the speed density tune? What all data and calculations go into a speed density tune? My son is liscenced with HP tuners and is swamped with work. Any head start that I can get to save him time will be greatly appreciated.


You won't run a MAF sensor at all & you will need a 2 bar or 3 bar MAP sensor.
Here's a video that overviews a Speed Density 2 BAR OS conversion.

 

[P10crew]

Thank you