Does anyone know if they are needed/optimal with the stock intake? Also, how is everyone making the simple home made ones? Im still curious as to what the catch can actually does.

 

I saw a very nice set-up over the weekend. His caught no oil. I think its more for a dress up then anything else on our cars.

Its suppose to catch the oil that gets "blown by" into the intake track.

 

Yeah FairladyZ actually saw my setup. I really don't expect much blowby from a stock car setup that is just daily driven. I'm sure a lot of WOT driving during autocrossing or a forced induction setup would see more buildup. Mine is pretty clean.