Oil Injectors Venting?

[ZGN]

Does it make any difference to vent the oil injectors to the open air or should they be vented into the intake?

Thanks,

Kevin

[Phoenix7]

I had this same question and was told that venting to the air wouldn't affect anything.

I'm interested to know what to do with the hoses (other than to leave them alone) since the stock TID has been replaced.

Edit: I came from the NEW POSTS link and didn't realize it's in the third gen section. It should still apply though, for the most part.

[afterburn27]

The oil injectors need to be connected to a source of filtered air. A convenient location for this is the turbo inlet. I just used a pair of small filters from the stock rat's nest solenoids.

[Brent]

I still put something on them, but I know landers has said it doesn't really matter.

[SPICcnmFD]

They need a constant vaccum it doesn't matter from where. They have a rubber valve/bladder inside that seals off under vaccum only allowing oil to go into the engine. If not it is possible it will go out the oil inj. onto the top of the engine, or into the intake. This can be a good source of oil in an IC/turbo if the rubber has torn and has a hole in it.

I took one apart a few years ago to see what was inside. I have no idea why they aren't just sealed up completely but I'd guess it has to do with some kind of pressure relief when the engine is cut off. I may some pics somewhere I'll see if I can find them.

[afterburn27]

Originally Posted by SPICcnmFD

They need a constant vaccum it doesn't matter from where. They have a rubber valve/bladder inside that seals off under vaccum only allowing oil to go into the engine. If not it is possible it will go out the oil inj. onto the top of the engine, or into the intake. This can be a good source of oil in an IC/turbo if the rubber has torn and has a hole in it.

I took one apart a few years ago to see what was inside. I have no idea why they aren't just sealed up completely but I'd guess it has to do with some kind of pressure relief when the engine is cut off. I may some pics somewhere I'll see if I can find them.

Close, but no cigar.

You are correct that it is only a simple rubber check valve, however your theory on operation is backwards.

They close under boost. The pressure from the intake chamber forces the valve shut which prevents boost from leaking out as well as oil. Under vacuum conditions the valve opens and allows FILTERED air to enter the intake chamber. This allows a METERED amount of oil to be injected into the intake chamber. If you cap the oil injectors (or if the valve is clogged/closed) an excessive amount of oil will be sucked into the intake chamber. Think of it like a straw... if you have a straw with a hole in the side up top you won't be able to suck any of your drink out of the cup, it will all be air. If the straw is intact then you will suck up the drink. If the oil injectors are plugged up during vacuum operation then the OMP has little to no control over how much oil flows into the intake chamber.

The next debate is whether you need to apply vacuum to the oil injector nipples. The answer is NO. There does happen to be a VERY VERY slight amount of vacuum in the primary turbo inlet under full throttle. This will in no way affect the operation of the oil injectors during WOT because the check valves will already be forced shut by the pressure in the intake chamber. During idle/cruise there will be virtually no vacuum in the turbo inlet and there will be a fairly large vacuum on the other side in the intake chamber. Conditions in the turbo inlet are AMBIENT. There is only a VERY slight decrease in pressure due to the increased velocity of the air. The pressure may decrease slightly more if you are running a crappy air filter. Have you ever installed a vacuum gauge on an N/A car? What happens during WOT? Vacuum goes to zero (or close to it).

In summary: The nipples on the oil injectors need to be supplied with filtered air. A convenient location for this is the turbo inlet (primary elbow on the stock setup). I just used a pair of solenoid filters from the stock rat's nest on my setup. The whole vacuum/oil injector theory is a misunderstanding.

[SPICcnmFD]

hmm...interesting.....that makes sense. That explains why they didn't just close them totally off so you wouldn't take a chance at having a leak or vac. line problem. Thanks for the info.