Chingon's Engine Build

I’m not sure exactly what pressure I’m getting at idle unfortunately, my post gauge for some reason isn’t readng, I have it T’d to the EGR valve and for some reason it isn’t giving me a reading. I’m assuming it’s not getting any vacuum or boost there. But I did find this one, it’s a billet case rated for up to 100psi but it’s not spring loaded like you said.





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Z Oil Catch Can Parts - Check Valve ( 0-100 psi )

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Yeah that wouldn't work for your intake system .. it's a unique setup .. what do other people normally do with a blow through intake like yours ??
 
I posted on a couple FB 4.6 build forums and they all just vent to atmosphere haha, definitely don’t wanna do that tho. That shit smells.

I found a spring loaded one yesterday but I can’t seem to find it anymore.
 
Chingon1 said:
I posted on a couple FB 4.6 build forums and they all just vent to atmosphere haha, definitely don’t wanna do that tho. That shit smells.

I found a spring loaded one yesterday but I can’t seem to find it anymore.
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Maybe something like this ..

1000010763.webp


It would be controlled by engine vacuum off the manifold - when the engine is at idle / high vacuum; the valve should open to allow flow through and then close as soon as your vacuum decreases/ boost increases. This would allow you to retain the metered PCV on your pressurized intake side without a breather or need to compensate the tune.
 
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Thank you!! I’ll check it out.


So today I took off the air/oil separator and ran the hoses exactly like stock and the crazy high idle is completely gone. It cranked like stock instead of the crazy idle it had before (2400+rpm) drove it around the block to see the AFR and at part throttle/crushing it was getting down into the .7 to high .6 Which I’m thinking is wayyyy too rich.

Now my other problem is I’m getting an oil leak from I’m assuming is the timing cover. So tomorrow I’m going to remove everything up front and fix that leak before I get back into the tuning. It’s ALWAYS something haha
 
Yea I think I am, since they are routed like stock. No check valve besides the PCV on the pass valve cover. Should I put some check valves on it before I tear it apart?? I should put check valves on both runs of the valve covers huh.

Again, sorry I’m just a noob at this whole system. Never had a boosted car so I’m wrapping my head around this whole setup. Thanks for your patience!
 
I'm not sure you have many options .. regular check valve won't work on that side ; you need bi directional flow, not a one way only valve. Putting vacuum on one side / pressure on the other side; would make the check open or closed at all times depending on which direction it is installed.

Unless you install the MAF / PCV line in front of the SC - at least it will drive normal. Anything else like disconnecting the PCV intake line will make your high idle come back and throw off your air / fuel.

Just got another idea; install a second IAC and wire it up on the PCV side .. 🤔 🤪
 
Haha another IAC?? I gotta look into it. I found a 3.5” intake tube that I can put on the inlet of the supercharger and hopefully tie the driver side intake port to it, since it’s on the intake side of the supercharger I’m hoping it won’t pressurize the system that way.

I think I’m kinda getting the gist of it. Atleast in an N/A system.

1. Driver side draws in fresh air via the intake tube

2. That same fresh air goes through the crank case.

3. PCV valve routes that same crank case air and dumps it into the plenum/manifold, only during vacuum at idle or part throttle. Besides that it stays closed, am I correct??

In an BOOSTED application routed STOCK.

1. The driver side Valve cover is drawing in boosted air via the intake tube that connected to the supercharger outlet.

2. Boost pressure enters the the driver valve cover.

3. Pressurizing the crank case.

4. Boost air is forcing its way through the PCV into the plenum; vacuum pressure is not closing the valve because the boost in crank case is keeping it open.

Am I correct??

If I’m correct in my assumption. I should grab the fresh air to the driver valve cover on the inlet of the supercharger before it gets boosted. That should help with my pressurized crank case. Right?? 😂
 
Chingon1 said:
4. Boost air is forcing its way through the PCV into the plenum; vacuum pressure is not closing the valve because the boost in crank case is keeping it open.

Am I correct??

If I’m correct in my assumption. I should grab the fresh air to the driver valve cover on the inlet of the supercharger before it gets boosted. That should help with my pressurized crank case. Right?? 😂
Click to expand...

Pretty much correct on all points. 👌

Number 4 above .. Is a little tricky - Pressure Differentials.

Vacuum in the plenum is what opens the PCV; when you're in boost, that pressure would forcefully close the PCV ( normally gravity does the work; the PCV is a ball inside a chamber and when it sits at the bottom it's closed ) .. a little plastic ball; so since your vacuum on the NA side is variable, the ball somewhat floats.

Now in your case; you have MOST of your boost PSI inside the plenum when it spools up - and you're boosting the crankcase via the drivers side connection, except now it's leaking out oil and boost pressure .. so you actually have pressure on both sides of the PCV. In any case; even if the boost pressure inside the plenum is higher than the boost pressure inside the crank case, the valve might in fact close or "float" .. except you're still losing pressure that could be used inside your engine via the PCV system.

Just remember the PCV is still metered air; it will work before the SC but it is supposed to be after the MAF.
 
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I have to draw this out in order to better understand. The 1st diagram is current, 2nd is what in thinking.

During idle/part throttle, the throttle plate is closed and the engine is trying to suck in air. This is called vacuum.

During WOT, what is happening?? Is the opposite true?? Is it pushing air out both valve covers and the plenum??

I’ll get back to you, I’m gona work on it over the week. Gonna consult the mechanic guru homie on his thoughts. He has a turbo ls3 300zx, pretty sure he can set me Str8

Thank you @dDUBb ill keep you posted!




image.jpg
 
Chingon1 said:
During idle/part throttle, the throttle plate is closed and the engine is trying to suck in air. This is called vacuum.

During WOT, what is happening??
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The pistons are creating the vacuum / this is a measure of restriction ( same with boost pressure ). Sort of like a your hand over a shop vacuum - it sucks even harder when you create restriction. So the engine pulls air through the IAC to keep from dying .. but the intake manifold also has vacuum hoses - some of these go to the AC or other parts; but it is all part of a sealed system. The PCV is like the IAC; except it's always open when the engine is running due to the vacuum pulling the PCV valve open and breathing through the intake tube. So the IAC makes up the difference in the amount of air the engine needs to run at a certain idle speed ( this is why it's important that your PCV and IAC are metered by the MAF ) .. if you choked off the air supply; the added restriction would increase the amount of vacuum; right before the engine would die.

What happens at WOT ?? In short - the engine is only being restricted by the amount of air it can pull through the air filter ... all the way into the cylinder itself. So vacuum on a gauge would be very low, even though the engine is sucking in a lot of air. It's air movement through equilibrium.

There are a lot of pressure variables - atmospheric pressure feeds a NA engine up to the throttle body, and the SC takes that air and pressurizes it even more because it is pushing into an enclosed space ( your intake manifold ) .. basically the engines vacuum is restricted to the space inside the cylinder / combustion chamber, and the positive pressure is on the other side of the intake valve. 😉
 
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@dDUBb sensei I have returned 😂

Ok so after a bunch of reading, it seems both valve covers turn into vents under boost, as in they both are pushing crank case pressure out via the PCV valve and driver side intake tube, Correct??


So I this iteration, I have 3 check valves and 2 catch cans.

1.a PCV get a catch can and check valve allowing vacuum at idle/part throttle
1.b check valve closes under boost closing it off completly.

2.a driver side intake gets a T fitting
2.b 1 run goes to intake tube with a check valve that stays open under idle/cruise, closes under boost.
2.c 2nd run goes to a catch can and check valve to inlet of supercharger.
2.d under boost intake tube check valve closes, supercharger inlet check valves open drawing in air from crank case allowing ventilation during boost.

This way the air out the engine is always metered. Would this work? To me it kinda seems like it should but gotta hit up the top dogs for feedback.

Thank you!



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Not quite ... 3 check valves and two catch cans is doing way too much

I'll draw something up for you in a few hours when I get off work today. 😉
 
Good looking out I appreciate it!

Technically the air/oil separator I have should work for both sides so it would only be 1 catch can. Definitely trying to do this on the cheap.
 
Chingon1 said:
it seems both valve covers turn into vents under boost, as in they both are pushing crank case pressure out via the PCV valve and driver side intake tube, Correct??
Click to expand...

Yes, when you're boosting pressure it's feeding into the driver side valve cover, you're boost might take a littke longer to increase manifold pressure because it's also filling the additional space of the crankcase and if the seals / gaskets are leaking, it's losing some pressure.

Crankcase pressure would normally refer to the expansion of hot oil / combustion gasses that are normally present during engine operation - this is why the PCV moves that air into the engine.

Chingon1 said:
1.a PCV get a catch can and check valve allowing vacuum at idle/part throttle
1.b check valve closes under boost closing it off completly.
Click to expand...

This is how a catch can is supposed to be installed - the check valve just prevents adding boost pressure into the lines / can ( which is additional volume to fill, wasted boost.

Chingon1 said:
2.c 2nd run goes to a catch can and check valve to inlet of supercharger.
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Two problems .. That's unmetered air .. and no oil vapor to catch in the can. The can goes between the valve cover and intake manifold because of crankcase oil vapor. No check valve would be necessary here.
 

Chingon1 said:
2.d under boost intake tube check valve closes, supercharger inlet check valves open drawing in air from crank case allowing ventilation during boost.
Click to expand...

The Crank case does not need to vent under boost. The PCV only works when the throttle is closed and under vacuum.

Chingon1 said:
This way the air out the engine is always metered.
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If it's not before the MAF, it's not metered. Air out of the engine = exhaust. The PCV wants to suck air into the engine. It only flows one direction. 😉

Chingon1 said:
Would this work?
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No. But I like your imagination.

1st drawing - see comments above

2nd drawing - boost arrows are going the wrong direction on the drivers valve cover.
 
I see I seeeee, so for my current setup (blow through), with out complicating it just to get it in the road and start the tuning process, no catch cans ; how do I go about it?? Right now I’m think a simple check valve in the PCV side should be good enough for now??

At this point I just want to get it running I don’t mind the catch cans. I need to remove the timing cover and fix that leak because it’s a pretty big deal and I don’t wanna run it drive.
 
Chingon1 said:
for my current setup (blow through), with out complicating it just to get it in the road and start the tuning process, no catch cans ; how do I go about it?? Right now I’m think a simple check valve in the PCV side should be good enough for now??
Click to expand...

I've given you a few different solutions for your setup .. here they are again

If you want to keep your blow through configuration - you need to install a spring loaded check valve into the PVC inlet, or a vacuum actuated control valve. A standard check valve will NOT work in this location.

Install the MAF and PCV inlet tube in front of the supercharger. No check valve necessary with this configuration. ( this is the easiest solution )

Or, remove the PCV inlet and make it an unmetered air source then compensate in the tune.
 
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