Simplified Sequential

[Herblenny]

Matt,

I just looked at the service manual online.. And you are right! It does blow into the engine side.. Opps!


But I still think its necessary to hook up the vac lines to the intake.. And here is the reason why..

I think the reason why mazda did this is to reduce the oil consumption when the engine does not need as much oil, ie idle. During idle, there is almost no vacuum created and air is being sucked thru the nipple of the jets.. As engine goes into load, the vacuum created by intake, blocks air going into the nipple and cause more oil to be injected into the engine. If you just put a filter there, air will still be sucked in vs. oil (but not sure what extend oil vs air will be injected into the engine). Well, that's the new theory I have.. I should have double check the flow of the jets instead of guessing

Also, you are right.. I also forgot that after intake ports on the iron is exposed, the oil meter jet opening is exposed at the same time. At that point, it will see pressure and hence 1 way valve must be one direction.. Sometimes I'm very stupid

[afterburn27]

Originally Posted by Herblenny

But I still think its necessary to hook up the vac lines to the intake.. And here is the reason why..

I think the reason why mazda did this is to reduce the oil consumption when the engine does not need as much oil, ie idle.

Yes, that is exactly why Mazda allows air to flow into the engine through the oil injectors. DamonB's "straw" analogy is great for explaining this.

Originally Posted by Herblenny

During idle, there is almost no vacuum created and air is being sucked thru the nipple of the jets..

Correct again.

Originally Posted by Herblenny

As engine goes into load, the vacuum created by intake, blocks air going into the nipple and cause more oil to be injected into the engine. If you just put a filter there, air will still be sucked in vs. oil (but not sure what extend oil vs air will be injected into the engine).

OK, here is where your logic gets a bit fuzzy...

The slight vacuum in the intake is not blocking air from entering the engine... the check valve is. There is pressure built up in the intake chamber (boost) under load, so the check valve will be closed. Even if you were applying moderate vacuum to the nipple it would have no effect on the oil injectors.

Again, remember that the vacuum created in the turbo intake is very very small (and only present under load). You could probably argue that the stock intake setup and a crappy filter might see a few inHg of vaccum, but that's it. Vacuum is only created after the throttle plates.

The oil injectors simply need filtered ambient/atmospheric air. The turbo intake is a fantastic location to source this, but individual filters will work just as well.