racerxrx7

I was wondering if you guys have the metering oil nozzle vaccumm lines hooked up. Is it necessary for injecting oil into the combustion chamber? Let me know whether to put them on or leave them to atmosphere.

Thanks

shawnk

I think you should have them hooked up to the intake side of the turbo.

higher boost = bigger vacuum in front of turbo = open oil meter valve = increased oil flow = increased lucbrication

I dont have any place to put a tube in front of my T04S turbo so I just have it to my manifold.

Vacuum at idle and low speed = open oil meter valve = increase oil flow = increased lubrication
Higher boost = closed oil meter valve = no oil flow = no lubrication

Not as good but better than capping it.

No vacuum = closed oil meter valve = no oil flow = no lubrication


Then again I could be completely wrong in which case I am sure someone will jump in and flame me... (either way this should expedite the answering process).

Shawn

HAILERS

The *vacuum* hose on top of the oil injectors should not be connected to a source of Vacuum. On a stock engine, the metal nipple on the back of the throttle body that it connects to.......leads to a path inside the throttle body that leads to an approx 1/4 inch hole infront of the throttle plates. It does not pull vacuum. Check it out by blowing smoke into the nipple and examining where the smoke exits.

The oil injector itself is pulling a vacuum from the inside of the engine and sucking air thru the throttle body.

shawnk

Hailers - I dont understand your reply exactly. Let me rephrase what I am saying and then you can tell me where I went wrong.

1. The oil metering injectors are a valve.

2. The oil metering pump is always applying oil pressure to the metering line.

3. Since the valve uses a pressure line to operate it either opens on positive or negative pressure. It has been a while but I think when I had mine out I tested it and it opened on negative pressure (vacuum).

4. If it opens on negative pressure, and the assumption is made that the oil is needed from idle to WOT (in a proportionally required amount) then the only place the source could be is from in front of the turbo (intake side). The more boost being generated by the turbo creates a vacuum there which would open the injectors more.

If the reverse was true about the injectors (that they open with positive pressure) then there would be no way to supply oil at idle since there is only one place of positive pressure at idle and that is on the exhaust side. Which may be the case because maybe the engine only needs oil above idle. Thanks for your reply hailers and I look forward to your next one. Oh and where do you suggest racerxrx7 puts his oil metering hose to?

Shawn

duboisr

I understand that the only place to get vacuum all the time the engine is running is the turbo air intake . You need to tap in to there for vacuum . when under boost the rest of the system is in positive pressure and the oil injectors will be off when you need them most.

HAILERS

Do this. The oil injector spider connects to the back of the throttle body on the large metal nipple. Take the hose off the metal nipple. Put a long vacuum hose on the metal nipple.

Light up a cigar. Blow the smoke into the hose going to the metal nipple on the throttle body. Look where the smoke exits. It exits in front of the throttle plates.

Vacuum exists on the BACK side of the throttle plates, not the front . The smoke will exit that approx 1/4 inch hole in FRONT of the throttle plates.

Or start your engine. Pull the spider hose off the metal nipple. With your finger, feel where the vacuum exists. It exists on the hose coming from the oil injector spider, not the throttle body. The vacuum is FROM the oil injectors. Its the intake stroke of the rotors that is pulling a vacuum , not the throttle body.

If you have a n/t car around it's easier to access the oil injector spider hose and do the above.

And no, I do not completly understand how oil injectors work. It has something to do with equalizing pressure on each side of the oil injector. But if you do the above procedures, you'll readily see that the vacuum is supposed to come FROM the oil injectors, NOT the throttle body.

I'd suggest racerxrx7 put the hose for his oil injectors where it originally came from......the large metal nipple on the back of the throttle body. The nipple that does not pull a vacuum from the throttle body.

On a 87turboii there is only ONE nipple on the back of the body that pulls a vacuum. That one is the bottom one that runs to the water thermo valve for cold start. The other nipple is joined with the large nipple inside the throttle body and is for the fuel injector air bleeds. Again, no vacuum for those either. Only a non-vacuum filtered air source coming from the front of the throttle body.

suganuma

fun with pictures....

HAILERS

shawnk.....I'm only familiar with series four and series five. Anything newer might work different. Racerrx7 did not mention what model. I assumed series four or five.

suganuma

seems like to me, it would have to work this way on any turbo engine.

shawnk

I agree. We did not get enough info to start with. And I assumed a 3rdgen (because I have one I guess). Racerxrx7 hasnt jumped back in so maybe we are just wasting time and energy anyway.

But I knew nothing about cars a year ago and have since pulled an engine and went through about every system on my car in mods or repair and was able to do so in large part because of info/instructions on this forum so I am still curious....

It makes sense that oil injectors are always under vacuum in a n/a car but in a turbo once boost is built the pressure in the intake chamber is positive (higher than atmosphere) so it seems there has to be 2 different systems of oil injection. The n/a is a much simpler prospect since it can just use the vacuum of the intake "stroke" to pull the valve open and of course the hose could not be capped (so hooking it to the throttle body/manifold or any filtered atmosphere source is definitely necessary). The turbo system would be more complicated because conditions in the intake "stroke" change pressure wise. So instead of having an always available vacuum source you would have to find one which is what I proposed with hooking it up to the intake side of the turbo.

Make sense? Anyone else have any input?

Shawn

HAILERS

I have two, series four TurboII and a non-turbo 86. The oil injector routing and the injectors themselves look exactly the same on both models.

Just for grins some time ago, on the N/T car, I put a long hose on the large metal nipple for the oil injectors and went for a drive to see if there was ever a vacuum from the throttle body. Nope, just a silly looking guy driving around with a hose from the engine in his mouth. No vacuum atall.

By the way, I think the path for oil flow is open all the time. I'll double check tomorrow. I have not messed with oil injectors for a while. If you blow into the nipple on top of them, the air will pass through the injector. If you suck on the nipple, there is no flow of air through the injector. I believe thats how they check them in the manual. But I kinda think that the oil path, which is a different thing than the above, flows all the time. Maybe tomorrow I'll get together with the MittyVac and some time. I'm not 100 percent sure of that oil path part.

Wargasm

Here is my idea on the matter.

This is only directly applicable to FD, but might be true of FC also.

I will say to you that the OMP bolts only pass air in one direction... into the engine. We know this is true from experience with the parts and also because the manual says that it is true.

I will also argue that there is NO WAY that a vacuum applied on the top nipple will affect oil flow compared to the flow with atmospheric pressure. Boost WILL affect flow however. I believe this to be true because I dissected one of these bolts.

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

Now that those things are out of the way... look at the attached pic.

This is what I believe is the state of relative pressures at various points in the system under a vacuum situation and under a boosting situation.

Location 1 Connection
--------------------------
If we connect the oil metering bolts to "location 1" which is the stock FD location, it appears that under vacuum, the pressure will be a little higher on the top of the bolt compared to the bottom. So air will go into the engine and help push oil in I think.

However under boost with Location 1, there is LOWER pressure on the top. I think that this will reduce the oil going into the engine relatively speaking. BUT.... DO NOT FORGET that the OMP is still pressurizing oil mechanically via the drive gear and ALSO the factory ECU increases the voltage to the OMP under boost!!!! So I think the net result is MORE OIL than at vacuum due to the increased voltage going to the metering oil pump. (I know that there is more voltage under boost by looking at PowerFC log files).

Location 2 Connection
-------------------------
If we connect at location 2, under vacuum conditions, it is much the same as with location 1. There is higher pressure on the top of the bolt at the metal nipple and lower on the tip of the bolt in the engine.

Under boost situations at location 2, there is again higher pressure at the top compared to the bottom, and the factory ECU is also going to be upping the voltage to the pump. So I think that this will give you even more oil under boost (maybe only a little more??) compared to the factory location.



Comments? Am I high?

Brian

HAILERS

EDIT: OOPS. Sorry. When I looked a moment ago there was nothing but a jpg and no words, so I just hopped in and asked a question. I'll mull what you said/wrote over. By the way, its been said that a broken oil injector will suck the pan of oil quick time. Like I say, I need to think it over and play with the things tomorrow. I do not have the electrical driven OMP. Just the old mechanical style. And I have taken one apart in the past. There is a very simple looking rubber poppet valve that opens and closes when pressure is put on it.

But if you have the time to answer the bottom question......that's just fine also.


So the question for Wargasm, is.......just about how far from the turbo exaust did you locate your wideband. And if you ever had it just behind the turbo and moved it further down the pipe, did you notice any difference in afr figures?

Wargasm

Uh we should try to stay on the oil metering topic here

But since you asked, I have NOT moved my wideband yet, it still runs in the stock O2 sensor location. I plan to move it to the far end of the downpipe for cooler running.

Brian

HAILERS

See my edit on my above post.

HAILERS

I'm having to take my time because I'm trying to remember the location of the hole in the rotor housing and trying to figure out just where it is in the cycle. Has to be on the intake stroke. Does that not mean that the pressure is lower on the bottom side of the oil injector vs the top side. Unhuh. Yep. I need to read what you wrote.

HAILERS

Yes, your picture makes sense. Just looking at the Blue, and knowing that the oil injector source of air is located infront of the throttle plates, the pressure on the nipple side will be higher than the pressure on the bottom side of the oil injector......Just like a n/t engine. The oil injectors suck. Not vice versa. No jokes, please.

And I moved my sensor from the original spot to about four inches from the end of the downpipe to figure out a problem I am/was having with the reading. A one off type problem.

machinehead

I know allot of people just leave the nipples open. I think all the vac lines are there just to insure clean filtered air, not add pressure... positive or negative. Could be wrong but that was my understanding...

Marshall

I'm with machinehead, its probably a clean air vent more than anything.

HAILERS

For what it's worth: maybe there is a misconception here. The oil path is open all the time. It is not opened and shut by pressure/vacuum (your pick).

Take a oil injector off when you get a chance, and take a look. The banjo for the oil is on the lower threaded part of the injector where there is no valving etc. It's a straight shot from that banjo to the internals of the rotor housing.

The higher air pressure on/from the top part of the nipple us used to diffuse the oil. Ever read those oil injector vs pre-mixing post on this site where the author says the oil *drips* into the combustion chamber??? The oil does not drip into the chamber. In my mind it more or less sprays or is somewhat atomized. Not spray as in fuel injector spray, but certainly not dripping into the chamber.

Bottom line for the original post: Do not put a vacuum on the nipple. Connect the injectors to the original large nipple on the back of the throttle body. A source of clean filtered air.

The only cavet to the above is that I'm talking series four oil injectors, nothing else.

shawnk

Ok...lots of good info here. Thanks for taking the time to do the video Brian - it makes it easy to see what 3rd gen oil injectors do. So the pump is always supplying oil since it is below the valve. I agree - easy to see no way vacuum on top will open that valve.

Hooking to intake side of turbo would be effectively capping it since valve would be always closed. Even to manifold seems like a bad idea now. At idle you cancel out the "vaccum" effect of the intake stroke because a vacuum in the chamber means vacuum in manifold so while it may be a small difference it would be pretty much equal. And you dont gain anything under boost either. In order for the valve to open there has to be more pressure on the top of the injector.

I also agree that regardless of what position the valve is in - there is no way the oil flow would be stopped. It seems that the air flow is simply for "atomization" effect as Hailers suggested.

So it seems working out a filter to atmosphere setup would be best since I don't think there is a nipple on a 3rdgen manifold that is not under vacuum (is there?).

But what about under boost? Anything greater than atmosphere in the "intake stroke" would close the valve. If the air is required for atomization it is not available under boost conditions.

I feel like I am chasing my tail. This system just doesnt make sense in a turbo car. Works fine in n/a as Hailer has pointed out.

Hooking to intake side of turbo, manifold, filtered atmosphere, or capping give exactly the same results under boost (no air flow). Only hooking to filtered atmosphere lets valve open at idle (vacuum).

???

Shawn

HAILERS

Seems like I read some words once, that if the top nipple were capped and not to atmosphere.....that what happens is the oil is sucked from the oil supply line at a rapid rate and it results in high oil consumption.

I give up on knowing all there is to about oil injectors....but thanks to Shawn and Wargasm I learned a touch more. At least nobody used the expression...*Oil drips into the rotor housing*...that drives me up the wall.

Grzes21

The purpose of the vacuum lines on the oil metering pumps is for emission purposes. The vacuum lines actually suck air in and prevent as much oil from entering the combustion chamber. If you're not getting any vacuum out of them then I'm also willing to bet that it's very hard for you to pass emissions. The only time those vacuum lines should be removed is for extremely modified motors that rev above 10 thousand rps otherwise you really arn't hurting or helping yourself. Just going to have to ATF more often cause your compustion chamber is getting dirty faster. (That's if you take them of)

Grzes21

Not oil metering pumps oil injectors my bad!

shawnk

Welcome to the discussion Grzes21. A couple questions for you...

Emissions is of no concern in this since most people who are looking at this for 3rdgens have removed all of that stuff. But then you say "lines suck air in and prevent as much oil" which implies that with them capped more oil would flow in which would be a bad thing (oil consumption, engine buildup) so it seems that they are there for more than just emissions right? Also how does the incoming air effect the oil flow? Keep in mind that none of us want to remove these lines at all - we just want to know where the best place to hook them up is after a single conversion (at least this has been my goal - Hailer pretty much nailed down the n/a question a long time ago).

Thanks for your participation.

Shawn