ok now i understand what a catch can is and what purpose it serves, my question now is are they
needed? cuz im building off of a free homemade kit i have and i was wondering if i needed to buy one
or not, my setup will never exceed 9psi or 200whp if that helps...

 

They are not necessary but are always welcomed. Depending on what motor you have then you can use the OEM one with the breather box instead of a true catch can. I know that I needed one on my B20 because there was not a breather box located there from the factory and hence no way to expel excess crank case pressure.

 

just build it then......

and sure it will help your engine life

 

Youll know if you need one when you put it on the dyno...

 

How do you tell if you need one from the dyno time? I'm gearing up for some dyno time, and want to get 300whp +.

 

thanks!

 

Its all about crankcase pressure and blow by. Depends on the turbo setup and amount of boost. Plus how much blow by you have into the cylinder head. I didnt have a catch can setup on my D16 and when it made 250whp at 7lbs of boost, it would blow the dipstick because of the pressure increase. So i was forced to run a catch can at that point. Youll most likely need one, so just bite the bullet and get one. Might as well do it now rather than later.