01tibby

but if its blow by air, it has little/no affect on anything involved in the next combustion.

faithofadragon

well technically if you think about it the air from the crankcase pressure has already been metered by the MAF so i think it would be ok to vent it from there

supercow

yeah, with comparison to the air going through the tb the air you might let out through the pcv or breather is nothing, the turbo guys aparently don't even have problems with letting out tons of metered air with bov's.

sounds to me though that as long as the breather doesn't take air in mad_john's way just might be the best. at least it makes the most sense (catch from both and don't have to disable the pcv). I'm pretty sure to be dot legal you'd need to be catching the oil coming off the breather.

JonGTR

Your crankcase really should be vented because the fumes break down the oil while its in the motor. But it is also better not to vent it back through the system. So the only way to do that is to close off the manifold port and buy a small vacuum pump to aerate the motor.
Thats not something anyone here would do, but a lot of professionals do.

The air that the PCV system takes in is not enough to negatively affect the MAF readings. The ECU will handle it just fine. If you have a MAP system or change your MAF to MAP, then you wont have any problems.

REDZMAN

Okay, so for a FINAL time, what's the way we should route everything Jon? For the cleanest intake.

There are 2 lines from the head/valve cover to the IM. Route both of them into a catch can with a breather?

JonGTR

There are several way of doing it.

If you're n/a:

1. Keep the PCV valve line stock. Then run the other breather hose from the valve cover to a catch can then back to your intake.

or

2. Have 2 catch cans. Repeat #1. Then the other one will have a line from the manifold, to the PCV valve, to the catch can, then to the valve cover. This way you're catching oil before it enters the manifold along with catching oil from teh breather hose.

If you're FI:

1. Keep the PCV valve line stock. Then run the other breather hose from the valve cover to a catch can without plumbing it to your intake. With this, you're creating a small vacuum leak during non-WOT, therefore bringing in unmetered air. But it's insignificant.


Look at the Axis drag Tib. I believe that the hose on the top of the valve cover is connected to a pump and catch tank. http://photobucket.com/albums/v214/SharkRa...t=axisdrag4.jpg

Ericy321

We need a nice DIY with pics. fing02.gif

OzFxCoupe

If you are naturally aspirated you can also connect the positive crankcase ventilation valve line to the catch can then to the intake manifold & just block off the other crankcase breather line.

My second line is currently blocked off (has been for months now) & when I removed the IM again recently there was only a very small bit of oil in it, coming from the PCV valve line.

If/when I get a catch can I will most likely hook it up this way.

supercow

jon, would it be beneficial to have the pcv have a catch can (like in your dual n/a setup). I was thinking about making a catch can with dual canisters. one side for pressurized (from pcv, out to intake mani) and one with a filter (in from breather, out filter).

col96fx

That would work fine, but you would need to block the hole on the intake elbow.