Richie1

I've just fitted a greddy t78 turbo kit to my fd but the kit came with no instructions and i was wondering what to do with the vacume pipes for the oil injectors. i put them into the back of my induction kit but it seems to be sucking in way too much and making the car very smokey. I was wondering what the rest of you guys do?

CCarlisi

They should be connected to an air filter.

Richie1

I have a k+N M's airfilter that i have connected to the turbo with 4" rubber tubing.
I drilled into this and bonded 2 pipes in (one for each nozzel) I think that now there is to much suction compared to the small front (twin turbo) and is therefore adding to much oil. when i had it running yesterday it was smoking badly but when i removed the pipes from filter it stopped.

Trevor

Run a single line from the intake and "T" it to both oil injectors. That's how most people do it. Might cut the vaccum down.

EKTwin93

Just cap them. If you really want to know what to do, do a search, and formulate your own opinion on what you find. Some people cap them, some people leave them open, some people run to boost, some people run to vacuum...everyone's got their own idea on how they work best. I personally have mine capped off, car runs great and there is no risk of vacuum leaks.

OWHAT

my oil imjectors leak a bit of oil when i go onto boost so i though if i plumb it into the air intake it would send all the oil through the turbo and through the cooler pipes = not cool

CCarlisi

Or do what Mazda does and run them to an air filter

I bet your emissions are a lot worse in vac. That might be a good way to get some solid data on what impact capping the air inputs has. However, Mazda certainly did it for a reason; I can't imagine them making the system heavier and more complicated for no benefit. Based on theory and what reputable engine builders have said, the air inputs reduce the amount of oil the motor draws in under vacuum.

That means the valve isn't working properly. You should replace it, they are cheap. One of mine broke and under high boost it blew oil out the air valve instead of into the motor

FJDRX7

iTrader: (32)

same here, and no problem

EKTwin93

Mazda also didn't run a T78 stock. Read up on all the different ways people have those oil injector linesset up. Everyone does it different, make your pick, but its a lot easier to just cap them and not have to worry about anything

CCarlisi

The two don't really have anything to do with each other.

Why do you think you don't you have to worry about anything with this setup? You make it sound like the other is more risky and that is not the case. If you want to play it safe I would run them as close to the stock setup as possible and that is by venting them to the airfilter not eliminating them.

atihun

This thread is a bit confusing, no?

From the original post, he's asking about the 2 oil injectors on the rotor housings, or at least that's the only place we have oil injectors.

Those, you can either T into one line and run it to an open nipple under the UIM, or run each seperately into it's own nipple on the backside of the UIM if you've removed the rats nest. The second one is what I did.

Note that you can't cap these without running premix.

There is no oil going into your intake pipes from the oil injectors.

This happens because you are not venting the oil system correctly.

Make sure that your oil return line from your turbo to the engine is as close to 0 degrees as possilble and that you are using a large tube, pipe or oil line.

You will get oil going into your intake pipes from having poor oil system ventilation, as you can get oil blowby in the turbo itself.

Do as CCarlisi says, plumb it as close to stock as possilbe. Most people with a single will put in an oil catch can that takes in the tube from the oil filler tube and another side goes to the UIM, with some having a small air filter on it.

Attila

Trevor

The oil injectors require vaccum assist in drawing oil thru the oil metering pump. If you connect it directly to the UIM the oil injectors will see boost which will affect oil flow at full throttle...which is when you need the most oil injection.

The oil injectors should be attached to a source of constant vaccum...the only source of which is between the filter and the turbo compressor.

Richie1

is the idea of running them to the airfilter so that as the suction from the turbo rises it draws an increased amount of oil through the injectors into the engine for lubrication?

dhahlen

iTrader: (5)

IIRC the way the oil injectors lines work requires them to be connected to a boost source (i.e. manifold) - the are required to be under boost since they are solenoids.

I got into an argument at the guys at speed machine and jon showed me how they worked.

My oil injector lines are now connected to my manifold and things work fine.

EKTwin93

They are connected to the manifold on the FC's as well. This debate will go on and on, but like I said earlier, everyone does it differently and its best to just make your own pick. But for all your information, here is how the oil injectors work.
Oil injectors 101

Ok the ONLY reason for the the vacuum source on the other side of the oil injector is to keep the motor from sucking in oil when you shut it off ( It also creates good suction to spray in the oil in the rotor housing but you could do this without the opposite nipple ). I'll explain how this works.

Lets start with the oil injector. The injector has a nipple on one side for a vacuum source and on the other side are the threads. On the threaded side there are 2 small openings for the oil to come into via the oil metering lines/pump and then one opening on the bottom to "shoot" the oil into the rotor housing.

From the nipple side you should be able to "blow in" but not "suck out". If you can your injector is bad and needs to be replaced.

From the threaded side you can "suck in" ( as long as you block the 2 small openings ) but you can't "blow out".

Now try sucking in and as you do put your finger over the nipple. You can't suck in now. This is what happens when vacuum is applied to the nipple...you have and opposing force stopping this. What this does it provide a sealed oil line so it can be sucked into the housing with force, therebye creating enough force so it kinda sprays when it goes through the oil jets down in the rotor housing.

So the motor is running and oil is being injected in the rotor housing ( the oil metering pump dictates how much but Im not going into that ). We have our vacuum source on the other side providing a sealed enviroment. Now we shut the motor off....we lose our vacuum on the other side and the motor ( which loses its spark the instant you turn off the key ) turns out its last revolutions. Remember when we don't have our finger on the nipple you can suck through the injector...well that is what is happening now. The motor won't suck the oil that is in the lines but will suck out through the other side of the vacuum line ( attached to a vacuum source only ).

Suppose the nipple side was capped off. You would have constant suction in the oil injector lines and when you switched off the car it would suck the remaining oil out of the lines ( and the lines are pretty long ). Considering you have no spark ( you lost it when you turned off the key and the car will still turn out its last revs ) the oil would just sit in the housing until you go to start the car again. Then when you started it you would have a bunch ( or a little ) of oil smoke at first. So this is why Mazda came up with this idea for the oil injectors. Phew!!!

Here is how the OMP works...
The Oil Metering pump is supplied oil from the high-pressure side of your engine oil pump, it is driven by a gear assembly in the front engine cover that is directly connected to the drive shaft. Within the OMP is a shaft that rotates with the engine RPM, this shaft has a hole (approx 1 mm) drilled through it, on one side of the shaft is the high pressure engine oil passage on the opposite side is a passage going to the oil lines that drip oil into your engine. So as the shaft holes align with the passages a small amount of oil is sent into the engine. The rotating OMP shaft can also slide in and out and is spring loaded, the oil flow is adjusted by moving the shaft in or out causing the shaft hole to align more or less with the oil passages. On the FC & FD RX7’s the shaft position is set by the ECU using a stepper motor with a spiral gear, as the stepper motor is turned its output shaft will move in or out. Using the stepper motor the ECU can precisely control the amount of oil flow by sliding the shaft back and forth. The other electronic component of the OMP is a potentiometer that tells the ECU exactly where the shaft is positioned which it translates into oil flow.

Make your pick, either way, the motor will be getting plenty of oil. Capping them is just simpler

Richie1

Wow you know a lot about rotary's! I tried to suck on the two vac lines running off the nipple on the top of the injector and was able to suck through them when the car was running. When these were plumbed into the air filter the car smoked heavily. Should i replace both of these or will capping them be ok.
Thanks for the info!

CCarlisi

EKTwin93, you basically just took what I said above, blew it off by saying the stock car doesn't have a T78, and 4 posts later came to the same conclusion with 10x the verbosity. Good job.

As for the MOP, I am 95% certain that oil flow is increased/decreased not by changing the alignment of the hole in the shaft with the input/outut ports but by increasing/decreasing the stroke length of the piston housed within the shaft. I know this is contrary to what everyone around here seems to believe, but if you remove the flate plate on the end of the pump, connect it to a front cover and watch it go through a several cycles with the stepper in different positions (like I have) I think you will agree.

EKTwin93

No my comment about the T78 was because the the stock turbos obviously don't produce the same amount of vacuum as the 67mm compressor wheel of a T78. The vacuum created by the stock turbos my be the perfect amount to counter the suction of the engine for the oil injectors, however, the vacuum produced by T78 may be too much force against the suction of the engine. I also commented about the T78 because, yes, I understand that Mazda did put a lot of R&D into the 3rd gen. ( that is an understatement really) but when people start to modify these cars to produce up to twice the power, the stock way of doing things is not always the best. I believe in making my set up as simple as possible, and like I said earlier, everyone has a different opinion on this so the best thing to do is do a search, maybe learn a thing or two about how it all really works, and then decide for yourself.

The two paragraphs I posted were from two seperate other posts, two posts that I read and developed my opinion from.

Richie1

OK I think I will just cap them off as long as this will not damage the engine . Thanks for all the help