Track

Its not legal anywhere really.

I am currently working on adjustments. I ran it vacuum today and the ------- thing is a bitch to work out leaks on. good thing I bought some HF hose clamp kit hahaha. anyways, I will have more updates, but so far I see oil in the lines, but nothing really in the catch can itself. It seems that the entrance and exit are too close together, so perhaps I will take other's suggestion and place them at 90* apart instead.

RedTurboMiata

Hey, would near the air filter be a good place, should be a bit of vac around there

MF-Brain

iTrader: (1)

the amount of vacuum in the intake is trivial. if anything just allowing the crankcase to breathe and expel pressure is good enough.

Track

yea found that out earlier. hooking up the breather to vacuum...total failure. I had a vacuum leak up the ***. So, intake = low/no vacuum. intake manifold, has vacuum, and a vacuum pump is a win. but a dry sump is the most win.

jumbosrule

Sort of coming to this thread late but wanted to chuck in another datapoint. I'm not FI so results may vary, but you might want to check out this particular configuration just for info.

PCV and passenger side routed to a catch can (dual inlet) and vacuum line (single outlet).

I ran this can for three months and collected only a drizzle of condensation. No oil at all, which surprised me since I have bad compression in #4 and some leaky valves.



After I got the ARC intake, the oil catch went bye bye since it wasn't doing anything.

As it turns out, this is also how I run a catch can on my boosted motor (VQ35DE) one can for each cylinder bank, with permanent vacuum (routed to intake between the filter and turbo). I tried FIVE other catch can configurations on this car before settling on this one - because it works.

Track

^I ran that. and it turns out to be a vacuum leak at idle. Unfortunately, the breather becomes a constant source for air since vacuum is unabated in that case.

jumbosrule

In this config there is no breather so where was your leak?

Track

there is always a breather. The breather is refering to the passenger side port hole which has no direction control.

In that configuration, the crankcase IS vacuumed, which is good. but your are also pulling in "unmetered" air into the intake through the passenger side port (breather).

PCV -> vacuum works because the PCV controls how much is being pulled depending on crankcase pressure and the vacuum in the intake.

Breather -> vacuum has no control, so your vacuum constantly pulls crankcase air all the time. Since vacuum is highest under idle and decel, you end up getting really ---- idle and fucked up LTFT.

Breather -> intake has very very little if any vacuum, so it does fine without a control system.

jumbosrule

What you are saying is contrary to my understanding of the system (all PCV systems). I'm a career engineer and I have a pretty good handle on the system.

There is no breather. Breather = vent to atmosphere.

There is a vent (passenger side) and that's different than a breather. The vent line from the passenger side is never pulling un-metered air since all air is coming from the intake, which passes through the meter. It doesn't have to go through the Throttle Body in order to get sucked into the cylinders.

Track

I am an engineer too buddy. doesn't mean ----.

The thing you are confusing is the location of vacuum. The intake tube (in your case, the tube between the turbo and the filter) has little if any vacuum. Vacuum is behind the Throttle body. Hence why yours works, its not VTA exactly but its not under much vacuum if any.

Now take the plug off your old PCV to intake manifold port and connect a hose from the passenger side breather to that port and you will have a vacuum leak. That's what you are saying by hooking both up (passenger side breather and the PCV) to a catch can and putting them under vacuum.

btw, "breather" is a term for the port used to allow PCV gases to escape. not to imply that the port is being vented to atm.