Fuel injection valve unit for an internal combustion piston engine, comprising - a fuel inlet connectable to a common rail system of the internal combustion piston engine for feeding pressurized fuel into the valve unit ; - at least one fuel injection opening arranged at an end of the valve unit for controllably injecting fuel; - a fuel space with which the fuel inlet is in flow communication; - a control space with which the fuel inlet is flow communication; - a control valve arranged in connection with the control space , which control valve is arranged to open or close a flow connection from the control space to a discharge channel ; - a fuel injection valve needle comprising a first end and a second end , in which the first end of fuel injection valve needle is arranged to open or close a flow communication between the fuel space and the at least one fuel injection opening , and in which the second end of the fuel injection valve needle is arranged to extend into the control space ; - the fuel injection valve needle is partially circumscribed by a cylindrical support section arranged between the fuel space and the control space and through which the valve needle is arranged to extend in supported manner into the control space ; and wherein - a contact area between the cylindrical support section and the valve needle is provided with a grooving arranged at least partially at an angle with the center axis (A) of the valve needle ; - the fuel injection unit comprises at least two independently operable fuel injection valve needles , each provided with a dedicated fuel space , control space control valve , and the cylindrical support section , characterized in that the contract area of the each cylindrical support section is provided with individually selected grooving , the grooving is dimensioned so that while the control valve is open the fuel flow through the grooving is 5 - 35 % of the total flow through the discharge channel . - a fuel inlet connectable to a common rail system of the internal combustion piston engine for feeding pressurized fuel into the valve unit ; - at least one fuel injection opening arranged at an end of the valve unit for controllably injecting fuel; - a fuel space with which the fuel inlet is in flow communication; - a control space with which the fuel inlet is flow communication; - a control valve arranged in connection with the control space , which control valve is arranged to open or close a flow connection from the control space to a discharge channel ; - a fuel injection valve needle comprising a first end and a second end , in which the first end of fuel injection valve needle is arranged to open or close a flow communication between the fuel space and the at least one fuel injection opening , and in which the second end of the fuel injection valve needle is arranged to extend into the control space ; - the fuel injection valve needle is partially circumscribed by a cylindrical support section arranged between the fuel space and the control space and through which the valve needle is arranged to extend in supported manner into the control space ; and wherein - a contact area between the cylindrical support section and the valve needle is provided with a grooving arranged at least partially at an angle with the center axis (A) of the valve needle ; - the fuel injection unit comprises at least two independently operable fuel injection valve needles , each provided with a dedicated fuel space , control space control valve , and the cylindrical support section , characterized in that the contract area of the each cylindrical support section is provided with individually selected grooving , the grooving is dimensioned so that while the control valve is open the fuel flow through the grooving is 5 - 35 % of the total flow through the discharge channel . <EOS>