help me figure this vacuum out (pics)

[glitched]

Just before BOV & intake manifold



Runs to a T fitting



Where one goes to the Relocated AAC valve



and the other runs to here

I dont fully understand how the vacuum is working in this setup. Is it negative pressure? positive pressure? does it change under acceleration?

Can I tap this line somewhere for a vacuum source for a catch can?

[Carl H]

that is the air feed for the idle air control valve and the auxillary air valve...dont use this as a tap for a catch can, best bet is to provide vaccum for the catch can via the intake tube leading to the turbo...it is always under a vaccum of sorts.

here is my setup:

side view:

havent decided if i want to run a downdraft tube or to pull it back into the intake...either way its better than vented covers.the catch can was also stuffed with steel wool and sealed for vaccum before i mounted it.

[robbie2883]

carl, out of curiosity what's the point of the catch can if you don't have something creating vacuum in it? it's not pulling any crankcase vacuum (scavenging) which is the point of those lines in the first place (to create negative crankcase pressure) just asking

also what fittings did you use to tap into the valve covers?

thanks!

[Carl H]

catch can is there to do just that, catch excess oil vapour that comes with the air produced by crank case pressure.You dont need to have the can hooked to vaccum but it will improve crankcase scavaging with the possiblity to introduce oil into the intake track.The can was mainly to clean up the engine bay and do away with the open valve covers which could allow dirt and grime to get into the engine, like i said i havent decided yet if i want to pull the can back into the intake track or not...the fittings in the valve covers are just 3/8" pipr thread to -6 an male...simple and effective.

[robbie2883]

nice...thanks for the info carl