Simplified Sequential

[Whizbang]

Originally Posted by Herblenny

David,

I know I had also wondered about that before...

What I know is that oil metering jets are one way jets. I also know what when air is being pulled by the turbo, it will create vacuum by the intake nipple. I'm assuming the vacuum lines on the oil jets are facilitating oil injection at higher load (under boost). I've seen people run this line to LIM manifold nipple, but I think when you do that it does the opposite affect and could also distroy the oil injectors.

i would have to disagree with this partially, at least in terms of what is happening. When a volume (the intake manifold) is pressurized, the pressure WILL go in the direction of lower pressure. Which is the reason the air is moving in the first place (towards the engine). The air on the wall of the intake plenum increasingly approaches a "0" velocity.

Now, what is probably happening, is that there is pressure working against the oil jets. This is probably the reason that there is a line running to the oil jets (at least on all the FBs, and FCs i have seen). It probably is to help equalize the pressure.

If you read my thread on air and its working, you might remember this formula. M=DVA (mass flow = density x velocity x area)

Mass flow must remain constant in this situation. We shall assume that for a given density (due to pressure and heat after turbocharger), you have velocity and area as a variable. The air moving inside of the smaller lines and vacuum nipples will be moving faster to make up for the decrease area when compared to the intake manifold.

Meaning that any of that pressure in the manifold is compensated for and if anything, a pressure differential may form in favor of moving air/oil of the jet and into the intake plenum. This, coupled with the pressure of an assume good metering oil pump, will mean oil is exiting the nozzle.

Without good testing, this is the best i could reason.