PCV Plumbing with Torqstorm supercharger

[rich_mc]

I recently finished install of the Torqstorm on my Slant 6. Got just under 100 miles on it so far and see that I'm gathering some oil on top of the valve cover around the PCV Valve. Now that I've noticed and am researching further, I feel like I might be missing some needed components such as a check valve or catch can.

Currently, I have the PCV that came with the Aussiespeed valve cover installed and have a hose running from it to my pipe port on the intake manifold. From thinking this through a bit more, I think there is positive pressure in both the intake and the crankcase. The PCV is designed to work with vacuum in the intake, not positive pressure, so it's probably not able to do what it is supposed to do.

I'm guessing what might be happening is that since there is positive pressure on both sides, the air is maybe just pissing out around the pcv valve gasket and dragging some oil with it... Does that sound feasible?

From some reading, I'm seeing that some people will install a check valve in the line to prevent the boost pressure from the intake making it back to the PCV valve. Others seem to also add a catch can in that line in order to let any oil that comes out of the PCV fall into the can rather than making it back into the intake. I understand all that. But what I'm not understanding is where does the air/pressure that should be exiting the pcv go if there is boost in the intake? Does it just build up in the line until crankcase pressure is higher than boost and then it can make it's way back into the intake? It seems in my engineer (but not automotive) mind that there needs to be another vent in there somewhere...

Few pics below of current setup, current leak not really very visible, and a freebie catch can that was included as part of the sale that was running back when I bought the supercharger on Black Friday.

Any thoughts or suggestions are welcome. Thanks!

 

[67Dart273]

I don't know anything about that setup but you CAN NOT plumb ANYTHING that needs vacuum TO THE INTAKE manifold, with a blower/ supercharger/ turbo. It must be a vacuum source, and if there is none on that setup you will have to use an external pump. This includes vacuum heater controls, etc

On a blower such as a 4- or 6-71, you could plumb vacuum accessories to the base of the carb, as those are "suck through."

I've no idea what to tell you about PCV Are you old enough to know about "road draft" crank case venting systems on older cars? (pre about 63 or so and earlier)

 

[rich_mc]

Nope - not that old...

It completely makes sense that they can't be hooked up to the intake - It just didn't cross my mind until afterwards and noticing the oil collection. The right solution will be figured out and implemented soon.

 

[Demonracer]

Are you running and EFI or blow thru carburetor?

 

[rich_mc]

Are you running and EFI or blow thru carburetor?

EFI... It's the Super Sniper 2300 - 2 barrel one rated for blow through applications.

 

[Demonracer]

Does the unit have a 5/16 or 3/8 port on the throttle plate? If so, that would be the place for the PCV hose for optimum evacuation.

 

[rich_mc]

Does the unit have a 5/16 or 3/8 port on the throttle plate? If so, that would be the place for the PCV hose for optimum evacuation.

It does have these ports. I guess I'm confused as to how those could generate vacuum if there is positive pressure in the intake manifold.

 

[dano]

You'll need to plumb it to the intake side of your supercharger. Use the catch can to keep things cleaner on the intake.

 

[rich_mc]

You'll need to plumb it to the intake side of your supercharger. Use the catch can to keep things cleaner on the intake.

That thought had crossed my mind. It would be pretty easy to add a bung in that u-shaped tube I have between the supercharger and the air filter.

 

[Demonracer]

Try hooking the PVC to the 3/8" port, even though your SC is blowing thru it it still creates a vacuum under idle and under throttle.

 

[TT5.9mag]

See my reply in your other thread.

 

[TT5.9mag]

It does have these ports. I guess I'm confused as to how those could generate vacuum if there is positive pressure in the intake manifold.

View attachment 1716258849

They won’t. Period. Once you have positive manifold pressure, all of those ports are direct paths to the crankcase. Plug them. And throw the pcv in the trash. Vent the valve cover to a catch can with as big of a hose as you can.

 

[MadScientistMat]

PCV valves function as check valves; they shut under boost and open under vacuum. It can be beneficial to add a catch can in between the valve and throttle, but they'll still work as normal on forced induction applications.

 

[67Dart273]

PCV valves function as check valves; they shut under boost and open under vacuum. It can be beneficial to add a catch can in between the valve and throttle, but they'll still work as normal on forced induction applications.

Yah, but under boost is when you need the crankcase to be vented the worst. I'm thinking you need to build a road draft setup and put BIG breathers on the rocker covers.

 

[go-fish]

Crankcase header evac is what I used on my Procharged 408. Not for use with fiber packed mufflers. Flowmaster and glass pack type mufflers are OK.

Kevko has developed the most efficient oil evacuation system on the market! This kit was designed to hook to any motor and utilize existing stand pipes with no modification needed.
This system mounts along the firewall and connects between the valve cover and the header. Tested by engine builders in the Midwest, this will create vacuum pressure in the crankcase, reduce windage, lower oil temps and can free up to 7 horse power!

K139 Evac Kit

 

[TT5.9mag]

PCV valves function as check valves; they shut under boost and open under vacuum. It can be beneficial to add a catch can in between the valve and throttle, but they'll still work as normal on forced induction applications.

In theory yes but in practice, nope. They are un reliable, not well engineered, and not designed to operate with any positive pressure on that side of the valve. I’ve tried. And I always end up getting rid of them. And I’m a pcv valve fan, every NA engine should have one, but I have yet to find one that is designed (and engineered) to work the way we’d like them to in a forced induction application.

 

[MadScientistMat]

I'm using an all metal PCV that appears to seal under pressure OK. You could probably adapt an Eagle Talon TSi valve if you want a metal valve from an OE turbo application for extra peace of mind.

That said, when I had my pre rebuilt, 200k mile motor on the Dyno, you had a lot of fumes blasting out the stock breather cap, so rigging a way to vent the crankcase under boost. Whatever you do, you don't want it to find a way to help it into the intake while under boost.

 

[rich_mc]

For now, I went with a Motion Raceworks catch can plumbed from both ports on the valve cover to the can based on discussion in another thread. I think it'll be good but will report back here if anything goes awry.