what is the point of an oil catch tank. i dont really understand the redirection. some one please explain and is it nessacery thanks

 

its not necessary, only if you want some bling under the hood.

it just catches oil that blows by, most people just have a hose off of their head leading to the ground

 

thanks

 

dont do what that guy says and put a line going to the ground.
you have a PCV valve and ventilation. Your PCV valve is behind the engine by the oil cap facing the firewall. its a 90 degree valve. The ventilation is the one on the right of the engine. If you follow the ventilation one you will see it goes into your air intake by your turbo area. Oil bypass will sometimes go here then into your turbo and through your intercooler. This is why an oil catch can is used, to stop this.
IF you going with one oil catch can, I suggest you put it there. You can also put another on the PCV valve also, this stops oil from going into the intake manifold.

the people who are running the line to ground are #1 not emmisions compliant, #2 you need that vacuum to suck out the bypass as much as possible, leaving it vent to atmosphere lowers this pressure and therefore will not suck out as much residue leaving "sludge" build up in their crankcase.

 

good explanation! plus, oil vapor lowers the detonation threshhold of the motor limiting your power production(not a whole lot). trust me, i didn't use one for about 38K miles and my intake pipe, MAF, hotside IC piping, and hotside of my IC had a nice coat of oily sludge on them that i had to clean off. the oily residue that gets into your IC also lowers it's ability to transfer heat to the air thus lowering it's efficiency and limited power production, increasing knock, and speeding up heat soak. your PCV valve(when working properly)should close under boost so you don't get oil into the intake charge hurting performance, but it will suck in this vapor under vaccum and can coat the inside of the manifold and intake valves with oil residue. if you decide to buy a can, i'd suggest this one, as it's the only properly designed one that i've come across that's not just "bling". hope this helps.
http://www.saikoumichi.com/