Simplified Sequential

[afterburn27]

Originally Posted by Herblenny

Maybe my wording is bit confusing..

What I meant was that the vacuum created by the turbo, pulling the air in (which you said is min. negative pressure) is enough to stop from getting the air into the combustion chamber. But also, the negative pressure being made by the combustion chamber could be small and short so small vacuum created by the intake could stop the air from entering.. If you look at the quote I posted, the volume of oil is 0.0005L or 0.5mL. Which is pretty small volume which tells me only need small amounts of vacuum created by the air speed thru the intake might be enough to stop air entering and causing bit more oil to be injected at higher load (high air speed thru the intake).

I also agree with you that once intake port opening in the engine the pressure of the combustion chamber will be positive and then the check valve will stop the air/fuel mixture to escape thru the oil injector port. But if it was still the case of clean air, mazda could of saved ton of money by just putting a filter on as you've stated.

I think the best way to figure this out would be to put a vacuum gauge on the oil jet nipple and see what kind of negative pressure it pulls. If it doesn't pull much, then my theory should hold true.. which is at high air speed thru the intake pipe causing higher negative pressure on the hose will stop air from getting in and increase oil flow... Otherwise, oil flow is just based solely on oil metering pump pressure and the air being sucked in thru the nipple. Which could possibly be true..

I *think* I understand what you are trying to say, and I still disagree. Are you saying that even under load (boost) the injectors will be periodically sucking air into the engine?

Here's a question for you... how are the lines plumbed in the RX8? Or a N/A FC? They are routed to the intake (pre-throttle plates). There is NO vacuum present in the intake. In fact, here is an interesting diagram I stumbled upon that seems to prove my theory:

http://www.rx8club.com/attachment.ph...0&d=1179886044

[Herblenny]

Hmm.. Seems like you are right..

Here is the RX8 diagram..


Looks like its before the TB.

Air is led from the throttle chamber to the check valve. The reason for this is to prevent the suction of a large quantity of oil by the vacuum when the vacuum of the intake manifold and combustion chamber becomes high during rapid deceleration, etc. Consequently, the amount of engine oil measured by the metering oil pump is supplied, regardless of the vacuum caused by the check valve.

I guess I was wrong Looks like you were right.. just to suck in air and no other purpose. The picture you linked really help me see how it works.. and I also forgot it went in one direction and somehow I was thinking it still sucked in.. I'm stupid like that sometimes..

Thanks for the picture and helping me understand