The reason the omp has a vac line is so it won't get clogged and it's just easiest to do that after the air filter so they ran vac line to it. Take your own risks on venting (not too large though)

what is FI?

 

The fuel injectors!

 

no.

can't vent that. You'd have a vac leak.

it's to allow air to bypass the butterfiles for the primaries

 

This is what confusses me about this yellow line. From the factory it is connected to a nipple on the crossover pipe which places it on the discharge side of the turbos. At idle you would have a vauum leak as implimented by the factory. I see no difference as opposed to just leaving it open when not in boost. When in boost, you would pressurise the line thus accomplishing something. At idle I have to assume there would be a vacuum leak but this is the way it is stock so it must somehow work. It needs to be connected but what is the design plan in regards to the vacuum leak.

There are two orings/insulators that are located where the primary injector block engages with the center plate. These are to seal the connection from having a vacuum leak. This is also where the air is supplied to. Is this supposed to seal under vacuum and only allow air to be pushed in under boost but not drawn in under vacuum? Any ideas?
Mike

 

The car uses a map system not a maf. A vac leak on a map system at idle won't affect anything if it's before the tb (the crossover is). The problem would only arrise under boost as it would "leak" and lose boost.

 

Are you refering to the injectors o-rings or the spacer between the rail/iron?

 

hmmm, this is quite the interesting post... i just recently installed an rx6 kit and i capped ALL of the stock vacum lines that connected anywhere on the stock twins. been running like that for over a month now with no problems... do i have to reconnect some lines or am i fine?

 

depends on what you left.

you could have as few as 6 vac lines (bov,map,fpr,wg,injector bleeder,brake booster).

-oh and MFilippello that's the purpose for the yellow line. To draw air in before the butterflies so that's why it's before the tb. When the butterflies are shut not enough air is getting sucked in on the primary ports to properly atomize all the fuel down low.

The preset map uses pressure and rpms to calcuate fuel (and a few others like fuel/water/intake temps). If the pressure is artificially low due to a leak it won't use the correct points. Pretty sure the pressure maps are in accordance with that line being so and that why it doesn't look like a vac leak to the engine.

 

ok well clearly my HKS BOV has a vac line and the wastegate is plumbed properly as well. now the map sensor was never gettin its pressure reading from the stock twins nor the brake booster. but now where did the FPR and injector bleeder plumb into the stock twins?

 

.

 

that pipe always has positive pressure...if the turbo is spinning air is flowing...might not be a lot, but definitely not a vacuum leak.

 

If that were true than how do you account for oil ever being injected when the manifold pressure is positive (under boost)? Hmmmm......


This cannot be right. If it were right then you receive no oil injection when under boost because as we all know there is no vacuum present anywhere downstream of the turbos when they are under boost. Manifold pressure is positive then and thus there is no vacuum to "suck" oil up the lines and into the motor...

The OMP is in fact supplied with engine oil pressure and it is engine oil pressure which drives the oil through the tubes and into the motor. The oil metering pump does just that; it meters the oil through a rotating gate. Here is how the OMP works:

FD OMP oil metering pump function

 

The line in the front cover is a return line and does have some pressure.


I can see with higher rpm it would be forced in with the higher oil pressure (addressing boost). If this was true for all rpm then the vac line wouldn't be needed.

Why is the vac line part of the designed if it's jsut forced in? I didn't see the mention of the vac lines in that thread.

 

The vac lines are not mentioned because they have nothing to do with getting the oil through the tubes and into the engine. The vac line is behind a diaphram inside the oil injectors; the vacuum in this line never sees the oil inside the tubes and injectors. The diaphram seals them from eachother.

The vac lines on the oil injectors are plumbed directly to the intake with no valves or anything in between and so vacuum is present here 100% of the time (engine running of course). If the vacuum is some how pulling oil up the tubes then the oil still wouldn't make it into the motor as the vaccum line would suck it right out of the injector the moment the oil got there and then send it through the intake.

 

any new pics of the diagram with all the un needed hose capped off???

what im tryin to say is the correct way of doin the vac lines

mike

 

Nope, feel free to make one!

 

There is a check valve (diaphram) in the injector that doesn't allow oil in the vac lines like mentioned earlier in this thread. This is evedent also by the use of a vac line. I never once implied oil flowed through the vac line.

https://www.rx7club.com/showthread.p...t=omp+injector

If they have nothing to do with the oil injection system then why are they even there (on all series). I still think they serve as bleeds like the injectors.

 

if oil is indeeded forced through the injectors how does these work

https://www.rx7club.com/showthread.p...=omp+Reservoir

the premix isn't under pressure

 

Since there is vacuum behind this diaphram (when hooked to the inlet as designed) two things happen: At the instant of startup the initial vac on the diaphram will help pull oil to the injector (imagine drawing back a very small syringe and then holding it there). Once the engine is shut off vacuum is gone and the diaphram then returns to rest and seals over the end of the oil tube (imagine putting a straw in a glass of water and then putting your finger over the end of the straw). This prevents the oil from siphoning down the tube. If the oil siphons back down the tubes they have to be re-primed the next time the motor is started and thus the engine is starved of OMP oil for a short time.



Just to make sure I'm not running in circles you do agree that the engine does not suck the oil up the tubes as you said earlier? Let's agree on that first and then I'll correct my earlier mis-statement about oil supply and pressure from the OMP...

 

The check valve is enough to not allow the oil back down. My FD has that problem b/c the check valve does not work as per the FSM.

there would be no vacuum with an efficient intake it's more of an "air intake" for the nozzles - it's just atmosphric pressure with clean air.

just as stated in this -It's used as a atomizer

https://www.rx7club.com/showthread.p...t=omp+pressure
(some wrong info in there though)

 

i guess my stance is closer to CCarlisi ideas in this thread

https://www.rx7club.com/showthread.p...t=omp+pressure

 

(not going to run in circles)









I agree on the nozzles though. Just checked the FSM and they allow airflow into the motor but not out. The vac line to the nozzle allows an alternate path to the nozzle under vacuum so that the motor doesn't draw too much oil up the tubes. If you were to cap the vac attachment on the nozzles the motor would get too much OMP oil when a vacuum is present in the chamber as without an alternate path to draw from it would suck up too much OMP oil. The engine is not to be allowed to draw oil up the tubes, only for the OMP to send it.

The presence of the one way valves in the OMP nozzles proves without a doubt that the engine cannot pull oil up the tubes via vaccum. The one way valves would provide a leak path to ensure that cannot happen.

 

Here is mine on a 93 automatic single turbo. I don't think I left anything out.

Tom

 

looks like you could have a better choice for your FPR...and I can't read whatever you wrote in there.

 

Try clicking on the drawing, bring it up and expand it out. You;ll see all the writing then.

Tom