I have searched the manual but can't find it. The larger of the two pipes on the y-pipe after the turbo's and seem's to go to the lower intake manifold?. What is it and do I need it to be conected as I have gone to a single turbo

 

A pipe or a hose?

There were no hard pipes attached to the y-pipe. If you are refering to the hard lines that run up from by the primary turbo, they just controll the sequential system.

X...

 

a pic of it would give us a better idea

 

why do you have a y-pipe if you have a single turbo set up?
pic please.

 

pics....I know the second gen. has a pipe leading back up to the air pump from the cat.