Upgrade stage up to 92 Hp for the 1.5 Diesel engine found in Smart ForFour. 

Stage 1 upgrade, is presented below.

Stock engine specs:    

Capacity: 1493cc                           
bore x stroke: 83 x 92 (mm)
Compression ratio: 18:1

Power: 68hp
Torque: 160Nm

Stage 1: 

Engine upgrades:

-Stage 1 Software upgrade

Engine performance:

Power: 92hp
Torque: 210Nm

Software upgrades:

Boost control is achieved using the OEM ECU and N75 valve.