I couldn't find anything on this but I remember seeing someone who replaced the plastic line that goes from the front CCV to the intake (airbox for stock). I used some cheap caliper at CAP and it was 14mm and 16mm so basically 5/8 and 9/16. However all they had was heater hose and I've heard that it was bad to use that because the hot oil vapors damage the hose. Does anyone know where to go to get the right kind or would heat hose do good for a while?