Volvo Penta D2-55 vs D2-75 same engine?

[haydude]

Mechanically they look like the same engine.

Same bore/stroke, displacement, RPMs, compression ratio ...

Where are the 75's additional HPs coming from?

 

[jordanbasset]

I've got the D2-55, think the D2-75 has a turbo charger

 

[Bobc]

The turbo