I just installed an intake system on my car, its a 00 si
However, my intake has two pipes sticking out, something similar to the photo.
I only connect the breather hose to the upper pipe by leaving the lower one open.

Question:

I've seen majority of the intake systems for B series motor contains one nipple or pipe for breather hose "which circled in Blue"

1: How about the pipe which circled in Red, what is that for?

2: What application or what year of civic/integra requires the lower pipe for sensor maybe?

Thanks

 

one of them is for your intake air temp sensor.