The Citroen C4 2.0 HDi 138hp (2004 - 2010) produces 138bhp and 320Nm in standard form. Our Stage 1 ECU tuning file raises output to 165bhp and 380Nm, a gain of 27bhp and 60Nm, with no hardware modifications required. The file is delivered through the ByteFLASH portal and is ready to write to the vehicle.