[Nathan Zachary]

and look at that wiki page, and read it yourself. see the pic? thats a Nomad engine. See that pointy thing after the turbo? thats the air intake for the compressor side of the unit.

[mamelukesabre]

Are you sure it’s not the exhaust outlet?

[MarkL]

Here's the direct quote from Wiki-

A Turbo-compound engine is a reciprocating engine that employs a blowdown turbine to recover energy from the exhaust gases.

The turbine is usually mechanically connected to the crankshaft but electric and hydraulic systems have been investigated as well.

The turbine increases the output of the engine without increasing its fuel consumption, thus reducing the specific fuel consumption. The turbine is referred to as a blowdown turbine (or power-recovery turbine), as it recovers the energy developed in the exhaust manifold during blowdown, that is the first period of the exhaust process when the piston still is on its expansion stroke (this is possible since the exhaust valves open before bottom dead center).

When a blowdown turbine is attached to an engine it will not reduce power due to exhaust gas flow restriction,

since a blow down turbine is a velocity turbine not a pressure turbine as is a turbo supercharger.

Mark

[Lx]

mamelukesabre is correct. You are wrong. They are taking the exhaust gasses to drive a turbine which coverts the exhaust energy to mechanical. It doesn't connect to another compressor to compress the intake air like a turbocharger. The output of the compound turbo is converted mechanically and is effectively added to the mechanical output of the engine.