What does an oil catch tank do?
 

as above and are they worth having? any use or just waste on hard earned money!?
i have a modified jdm 93 with 295bhp so would i myself benefit from one?

cheers

tim

Turbo charged engines are prone to the accumulation of an oil sludge mixture inside the intake tract. Oil vapour is forced out of the cylinder head and directed through vacuum hose into the intake system to meet clean air regulations.

The added oil within the intake system can lower the octane rating of your fuel and create a carbon, oil sludge build-up in your intake system. Oil vapour condenses onto all surfaces within your intercooler and intake system lowering the thermal efficiency of your intercooler.

thanks for that then!!! so i guess it may be worth having one!!! cheers mate!

Your WRX has three breathers that route exhausted engine breather air back into the inlet tract. One from each cam cover and one from the back of the crankcase, below and to the driver's side of the throttle body.
Now if a slug of breather oil, which is heavily oil contaminated, passes into the inlet tract and onto the combustion process, it could cause DET if you are mapped close to the edge and you were on power at the time.
With a catch can you divert the breathers to a tank and then it exhausts to atmosphere.
You can see a catch can kit here: www.geocities.com/harveysmith3000