Not long after the -6 entered service, an increase in thrust and therefore core power was required. Unable to increase (HP) turbine rotor inlet temperature, General Electric chose the expensive path of reconfiguring the CF6 core to increase its basic size. They removed two stages from the rear of the HP compressor, leaving an empty air passage where the blades and vanes had once been. Two booster stages were added to the LP (low pressure) compressor, which increased the overall pressure ratio to 29.3. Although the 86.4 in (2.19 m) diameter fan was retained, the airflow was raised to 1,450 lb/s (660 kg/s), yielding a static thrust of 51,000 lbf (227 kN). The increase in core size and overall pressure ratio raised the core flow, decreasing the bypass ratio to 4.26.