Detroit Diesel and Daimler really did their aerodynamic and thermodynamic
home work on the DD15.  The inner smooth pipe connecting the turbo
charger with the power turbine is insulated to retain as much energy
as possible out of the turbo charger.

The long pipe required out of the 3 rotor turbo chargers
will lose a little heat so I am thinking of wrapping
it with asbestos.

This SS pipe was $110. A real bargain. I could not have made
it at anywhere near that price.

Paul Lamar