Air leak.....?

[05chevy]

A buddy of my has a 6.4 and at idle you can hear air hissing from behind the turbos. Cant feel any air or exhaust leak. Truck only shows 20psi on the boost gauge. Truck is bone stock. Anyone run into this problem? Thanks

 

[FallenAuthority]

Cracked up pipe or pipes.

 

[Big Angry Hillbilly]

Up pipes or gasket between turbos.