rx6rx7

i went non-seq and took out all vacuum lines and solenoids, what do do with the oil nozzle vacuum lines, or can I just eliminate them?

DChan415

bump

anyone got an answer?

duboisr

You connect them the nipple on the pri (front ) turbo air intake elbo (black plastic bolts to the turbo ).

karken29

hmmm not sure

jr426

If you eliminate them than your oil nozzels will not work. They need vacuum (no boost) to work. There is a good explaination in the general rotory posts of how they work. The short answer is that duboisr is correct.

DChan415

sup guys, i found the answer if anyone needs it.

They need a vacuum source that doesnt see boost. So I connected them to manifold vacuum with a one way valve.

DamonB

This means when you are under boost you have no vacuum to the nozzles since they are seeing manifold pressure. Bad idea. Do as duboisr says and connect them to the primary turbo intake elbow; there is vacuum here at all times.

dubulup

Do what Garfunkle says...

DChan415

Ok, second question then.... Is there enough vacuum at the intake pipe for us single turbo guys?

Wargasm

Unless I'm mistaken....

The stock setup on a [3] is to have them connected BEFORE the turbo inlet (basically to the air box). There is only a small vacuum there... and there is no boost.

The stock setup on a [2] TII engine was to have them downstream of the throttle body where they would see boost or vacuum.

On my car, I have them hooked up to the pipe coming off my turbo so they will see boost or partial vacuum like on the stock setup. (no high vacuum since they are upstream of the throttle plates)

Wargasm

Furthermore, the book test for them says that the air should pass from the vac port IN and flow OUT through the oil delivery port.... Wouldn't this increase the amount of oil delivered under boost pressure when you need it the most? At vacuum, the nozzle isn't supposed to flow back the other way, so the oil would just dribble out right?

Brian

DChan415

Actually, I believe vacuum opens the nozzles so oil flows into the engine. When there is no vacuum or if there is boost, the nozzles will not flow oil to the engine. So they should be hooked up to a source that provides vacuum anytime the engine is on.

dubulup

This is getting interesting, I asked this in another thread, but are these lines okay to be replaced with silicon?

DamonB

The vac lines to the nozzles, yes. The oil metering lines to the nozzles, no.

dubulup

Thanks

Wargasm

Actually not trying to start a flame here but Mazdatrix told me that it's safe to replace the plastic oil lines with silicone with zip ties... Personally, _I_ wouldn't do it, but that's what they told me on the phone.

B

dubulup

Hmmm...don't think I'd do that either.

Wargasm

OK guys and gals....

Let's sort this out once and for all how the oil metering bolts work and how they are affected by pressure.

I have sawed one of these oil metering bolts off my 1993 in half and I can see how it works now. I might be able to put up some pics if anyone is interested.

How it is constructed
------------------------
The bottom half of the bolt is just like a regular banjo bolt... no tricks here.

The top half with the hex head on it contains an air chamber that is open on the top by way of the nipple for the rubber hose. The bottom has 4 holes drilled in it, and there is a circular rubber flap on the _outside_ of the chamber on the bottom side.

In this way, if there is lower pressure in the lower half of the bolt, and higher pressure inside the air chamber, air flows into the top nipple, through the air chamber, past the flapper and into the bottom banjo bolt part.

If there is higher pressure in the lower half of the bolt and lower pressure up in the air chamber, the rubber flap will prevent oil from flowing up through the air chamber and out of the top nipple.

----------------


My theory of operation
--------------------------

On a 3rd gen, the tops of the bolts are connected to the primary turbo inlet so they will always see some sort of vacuum because of the air moving through that pipe to go into the engine. Actually, I guess the more boost you are at, the more vacuum you would see at that spot due to the air moving through the pipe faster. But that's not my point really.

Thinking about idling or part-throttle cruising, the pressure at the bottom of the oil metering bolt where it screws into the engine will be lower than the pressure on the top nipple. The reason that I make this assertion is that without the aid of a turbocharger in operation (spooled up), you MUST have the lowest pressure in the intake cycle of the rotor housing area... otherwise, air would not get sucked into the engine and it would not run.

So under idle or part throttle conditions, I will say that the pressure on the bottom tip of the oil metering bolt is lower than the pressure on the top part and this differential possibly helps oil to find its way down into the engine. Do not forget that the oil is under pressure too, so it is not relying solely on that pressure difference to go in there.

When you are boosting, the situation is a little harder to think about. You will have a little bit lower pressure than before measured at the turbo inlet duct because more air is moving through there faster, so more of a vacuum is created. The pressure inside the rotor housing would be higher than before (I think) because the rotor is moving at the same speed, but you're cramming more air in there because the turbo is making boost. So in this case, compared to the part-throttle scenario, we will actually have LESS "helping" effect on the oil from the oil metering nozzle.

Does this suggest that the stock setup actually results in LESS oil delivered to the engine under boost?

Before you say, "That couldn't POSSIBLY be the way Mazda made it you fool!", don't forget that it's possible that the oil metering pump compensates by injecting MORE oil as the boost goes up. My logging with the PowerFC + Datalogit confirms that the OMP gets a higher voltage signal based on boost pressure.

So.. hmm there you have it.

So having said all that, what's the POINT of having the whole system with the oil metering influenced by pressures? Why not just tell the metering pump to inject more oil? Or make it run at a higher pressure... I dunno.

Let's go back in time to the 1987 Turbo II engine (I used to have one of those ).

On the 2nd gen TII engine, the oil metering bolts _probably_ worked the same way. On that engine, the nipples were connected to the intake manifold, not the turbo inlet duct. The major difference being that under boost pressure, the tops of the oil metering bolts would see full boost pressure. So you'd definitely see more oil going into the engine under boost right? Why would they do it that way? Remember that on a 87 TII, the metering oil pump was mechanical and was ONLY controlled by throttle position. Perhaps Mazda had to do it this way to add a little more oil when under boost.

I do know that on the 2nd gen N/A engines, they were hooked up the same way as on the TII, so I dunno how to explain that.... I wonder what the situation was on the 1st gens?

Oh well.. If anyone actually made it through the post to here... perhaps you'd like to offer some comments?

Brian

DamonB

Only thing I would add is that since the OMP on the third gen is electronic, the only thing affecting the volume of oil into the chamber is the OMP. The injector nozzles do not function with a duty cycle such as a fuel injector does, they merely emit what oil the OMP sends to them.

I have not opened up an oil nozzle like you have, but I bet the source of vacuum on top merely acts as a valve to open and close the nozzle. With vacuum present (anytime the engine is running) they allow oil to pass. Once the engine is shut off and the vacuum to the nozzles subsides (remember, no check valves here) the little valves close and prevent the oil within the OMP lines from siphoning off back into the OMP. Picture fluid in a straw with your finger over the top. As long as you keep the end of the straw covered, the fluid will not drain out. If this were to happen the seals would be momentarily starved when the engine was initially started the next time.

Pure supposition on my part, but it makes perfect sense.

Wargasm

I should post up a picture...

You would see that you could put as much vacuum as you ever wanted on the oil metering bolt and it would do anything "big" to the flow of oil... let me find my digital cam...

B

Wargasm

I made a 5 meg divx movie showing all the stuff I am talking about:

http://www.zeroglabs.com/rx7/howoilmeteringworks.htm

Regards,
Brian