what is a catch can? is this necessary? any pics? ive searched but just found people talking about it, none of my questions answered.

 

maybe this will help...

http://aie.safeshopper.com/144/cat144.htm?755

 

isnt there already a catch can under the intake, the little black metal box?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tgh99si &raquo;</TD></TR><TR><TD CLASS="quote">isnt there already a catch can under the intake, the little black metal box?</TD></TR></TABLE>

that is just a baffle, it's suppose to seperate oil from the air, but it doesnt do that great of a job.

and i will agree with you that there are a lot of mixed ideas on this subject. i too would also like to get a straight answer.

from what i've read, you can use a catch can between the PCV valve and intake/vacuum line. but under boost the PCV valve will close so their is no vacuum allowing you to suck up the excess oil and seperate it. so what some people have done is connect the vacuum source to the turbo's intake, to always get a vacuum source. am i right???

 

You do NOT want to assist in the crankcase evacuation by the bernoulli effect created through a flush or slashcut(facing away from airflow) port before the turbo on the intake.

What you are probably thinking about is the line running to the valve cover breather... more on this later.

You do not want your turbo and the incomming air ingesting all those oil vapors.
Either vent the crancase into open atmosphere with a filter or open-loop filtered catchcan. Or you can try other trickier means like exhaust assisted vacuum, or a vacuum pump.... this gets complicated however..