K this is for a friend. He has a b20b swapped dc2 and he wants to put some low boost to it (6lbs) untill he has the money for a bottom end build. Hes wondering if he should get a catch can that has a drain back to the motor or one that ventilates into the atmosphere.

 

It really isn't necessary if he's not making gobs of power. I mean it does help but by no means does he NEED it with a low boost application. If he starts making some serious power crank case pressure should be alleviated as much as possible.

 

Yea he is planning to step it up more later on with an overall goal of 400

 

the catch can must have some type of atmospheric vent to release the crankcase pressure. it should also have a drainback so that it doesnt overflow and get oil everywhere. there are like 8 million catch can threads. take a peek at the FAQ for the offical crankcase thread