If what you are saying is the dr side is plugged and the pass side is left stock, and the intake boot hole is plugged then one would think the only air would be comming through the throttle body/maf.

Not to debate wether or not there is unmetered air, but why would you want to run the crankcase at 20+ " of vacuum? I would assume that much would cause extra oil to be pulled from the crankcase and for the seals to suck in. Eg if the pcv system was totaly blocked off you would push oil out the seals but from what I'm reading the opposite would be happening. (basically I'm just wondering if your causing more problems then what you are trying to get rid off - btw no offense just wouldn't like to see you damage your truck)

Stock the pcv flows the crankcase vapours with most durring cruise which actually helps keep the crankcase clean but I cant see there being much or any flow with your set up. ( i think - pretty sure i'm close on this but at anyrate a stock pcv system runs at about 3" of vacuum, while I'm assuming you would be in the 20+ " of vac)

 

Unmetered air, is air that was able to get into the intake (after) the MAF and therefore uncompensated for by the EEC in the way of providing fuel, right? Well, since I have completely plugged the hole in the rubber flexible intake boot, as well as the hole in the driver's side valve cover, any air getting into the plenum is coming from the passenger side valve cover only. The only air in that source (valve cover) comes from combustion by-products, which were metered before they reached the combustion chamber, because there are no other holes, leaks or sources to introduce air into the system, unless we are taking the position that the engine's gaskets (oil pan, valve cover, intake, etc) leak air into the motor. Then, I would agree that I am getting unmetered air into the plenum from the passenger side valve cover. Please explain where you feel the unmetered air is actually coming from, remembering that all air that passes through the MAF (including blow-by, etc) is metered air. Is this wrong?

 

Dude, many of the fastest (drag) race cars in the country run vacuum pumps to create vacuum in their crank case, because it increases HP. For one thing, it increases ring seal. Major engine builders encourage it. I ran a 4-vane Moroso vacuum pump on my low 9 sec Mustang, and I was getting almot 20 inches of vacuum. Vacuum in a crank case is not a bad thing.

 

you say air from the system is being vented into the atmoshere......

what system is that ??....could it be you air intake system...if you have the line hooked up to the rear of your plenum, then YES your intake is open to the atmoshere via your breather and there is your path for unmetered air.....and yes there are many trucks that can run a breather along with an open PCV system and the computer keeps up and does no throw a lean code, some get their chips calibrated for it ....but its still unmetered air and its still not fresh air and it still has oil mist and I wouldnt take the chance no matter what your wideband says ...... the EPA is not venting my crankcase vapors into my intake to feed my combustion process but it appears I'm alone

 

Actually i was refeering to the topic where you asked if there is anything wrong with your set up.

I know drag race cars use vacuum but i was only question the long term effects on a vehilce that see's every day useage. If your truck is not used that often thats great but to some they are daily drivers which are measured by miles and 1/4 miles.

For example would not having the actual pcv " flow " create more sludge and moisture in the crankcase?

 

remembering that all air that passes through the MAF (including blow-by, etc) is metered air. Is this wrong?

"no your right, that is not wrong in a closed PCV system" a system which includes the crankcase as a closed component of the intake. Air Metered and passing through the crankcase taking blowby and gases along with it on its way to be burned.

Measured air cant pass through your crankcase because you plugged the entrance ....now it just passes through the T/B into the plenum where it mixes with (air entering at the PCV outlet at the back of the plenum that did not pass over the MAF) and continues to the cylinders...




Blown347Hatch .....The only air in that source (valve cover) comes from combustion by-products

listen to yourself.... combustion by-products ... that air is metered burned and gone...the air coming from the pass cam cover in your setup is not part of the intake system ....its just a hole in the back of the plenum ..

 

Mike Murrillo here in S.A. just runs breathers on his 8 second mustang....

High Horsepower, High compression engines setup with low tension oil control rings like our trucks are a real good application for PCV bypass.........our boosted engines suck that oil in.

 

The air is not gone, or else there would be nothing for the vacuum to draw. I believe you are saying that the air that is being drawn in is used up, therefore it is unmetered air.

The air in the crank case is air that got there by going through the mass air meter. There is no other way for it to get there. By the opened system that it used to be (from driver's side tube into the rubber boot), the passenger side valve cover evacuates the blow by through the engine by sucking air in the driver side valve cover (by the vacuum created inthe crank case) and then sucking it through the passenger side valve cover. It was metered air because it was drawn after the MAF because it was being taken from the rubber flex boot. But, nonetheless, it was an opening to allow a crossflow of air from the driver side valve cover to the passenger side vacuum source. Now, with my present set-up, I still have the vacuum in the motor, but instead of that cross-flow the factory designed, and I would point out that the suction source at the back of the plenum (which remained the same) just builds vacuum in the crank case, instead of (not) building it from with the opening on the driver's side. Basically, I sealed the (metered) leak on the driver's side. If there is no "outside" air getting into the motor (crankcase), then I believe the air being vacuumed by the PCV is still technically metered.

 

Some run breathers, although I've probably seen more boosted applications running vacuum pumps, than not.

 

we are getting close, to understanding each other.....its tough without talking in person, but we are close.


you are mixing your thought process between a closed PCV system and with what you have done (plugging the boot)

Think about your statement I quoted for a moment.

since you plugged the boot metered air passes into the plenum........any entrance in the intake like that hole in the rear of the plenum is downstream of the MAF and is is now unmetered....it is now irrelavent that it comes from the crankcase !! how is blowby metered that exits into the plenum ? you only have a outlet exit from the crankcase to your plenum.

if you freeze/pause the movement of the motor with your boot plugged......metered air is entering the plenum...and just ahead of this metered air is crankcase venting entering the rear of plenum also.........





Your statement is only correct if you have not plugged the hole in the boot. Metered air flows through the crankcase to be burned.


.. I would not plug the boot.
1. lean condition
2. your still providing a path to the fresh air intake with huge vaccuum at the rear of the plenum and that vacuum gets its air source from crankcase gases and oil mist .......only.

 

I think that the PCV valve should work as a check valve, but I think that he put that there mostly for some of the newer cars/trucks like mine that didn't even have a check-valve in the PCV(not sure how it is on the lightnings), it just had a small hole to limit the airflow, so it would theoretically blow pressure back into the crankcase if I had a centrifigal blower/turbo that actually pressurized the intake manifold. It would have done that anyway wether or not I had the catch can though. You could always put an extra check valve in it, but I don't think that it is necessary.
If you want I can talk to the guy who makes them. He is a GN owner who comes out to our local car club, and is a really awesome guy. He said if there was interest he would make a kit just for the Lightnings

Btw, here are links to the pics that I have of my catch-can:

inside of catch can
On my truck
another
and yet another

Aaron

 

HI!... All I know is that on my N/A 5.4, I plugged the vac line going to the air intake tube from the D/S valve cover. I then installed a valve cover breather in the D/S valve cover. I then installed a oil seperator between the PCV and the intake manifold. Not a drop of oil has got into my intake or on my TB now. MIKE TROYER tuned me for this set-up. Truck runs great and A/F's are consistant 12.3's all day long on the dyno. Remember I'm N/A.

Her's a pic of my oil seperator, while the truck is running :



If you look at this pic in the topmiddle R/H corner, you will see the D/S valve cover breather I am using :