RedTurboMiata

i Saw your post on mt and wondered why u took the line off the intake to the cam cover.

Here is the thread:
http://www.miataturbo.net/showthread.php?t=61704

Track

Well, its somewhat simple and somewhat not. The intake breather is there to provide an escape for crankcase gases in high RPM/throttle situations where you have no vacuum to keep the PCV open.

So in reality, its function is non vacuum based, so it doesn't really need to be connected to the intake.

With that said, Its hard to keep vacuum when the otherside is open right? so I will be running individual tests to see which ones end up with the most gunk in the catch can. I am resisting the urge to improve my catch can at this time for this, but my next RA event I will be running with the breather connected at a y to PCV into a catchcan which is under vacuum. Here is what I plan to try in N/A:

1) breather to catch can to VTA and pcv to normal (done, nothing in the catchcan but it strongly smells of fuel and oil)
2) breather + PCV to catchcan to VTA
3) breather+PCV to catch can to vacuum
4) breather to catch can to VTA and PCV to catch can to vacuum

You are turbo charged, your needs are much different than mine. most people state to either run a check valve at the PCV, or to hook both ports up to a catch can then VTA that. I think it depends on the amount of boost you are running also. Or if you want to get fancy, work something out with a vacuum pump.

RedTurboMiata

i was thinking pre turbo line with a catch can? my thought is pre turbo always sees vac. but thats open for debate

Track

I do not know, the issue is vacuum is based on the throttle body. fully open (no restriction), there is no vacuum in the intake manifold (I don't know if there is vacuum in the crossover at any point or not). Will a turbo being added before make a difference? My belief would be yes, because between throttle and the turbo will be boost, so the turbo itself must create its own vacuum on the intake side for that idea to hold water. And it very well could, I don't know about that as I haven't considered the turbo options yet.

You can look at diesels I think for info on this. As they tend to run different PCV systems than us due to the vacuum principle or theory or whatever stated above.

Due note, that I am posting this from reading on internet forums, I have no actually read about fluid dynamics enough to understand or explain it beyond this. but that should be enough information to look it up if you are curious.

RedTurboMiata

right now my car is in the factory pcv setup with a breather on the other side. is that a problem?

Track

I do not know, where is the breather hooked to?

Probably fine under low boost, but I would definitely get a catch can setup going. even the MSMs had a catch can of sorts.

RedTurboMiata

its on the driver side side little breather port, if im correct it use to be the crossover part.

Track

yes, but you are FI'd now, so where is your breather connected to? post or pre turbo? or is VTA?

I think vacuum is good. as shown by manufacturers who used to do VTA, they would run a tube down to an area under the body which was kept under vacuum through some form or aero manipulation. so thats why I am curious to see how much ---- I can pick up with vacuum all around.

RedTurboMiata

im stock on pcv, crossover is vta

MF-Rick

I dont believe this is legal in Ontario, Canada (if any Canadians were curious..)