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 (2,22) comprising a first end and a second end, in which the first end of fuel injection valve needle (2,22) 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 (2,22) is arranged to extend into the control space; - the fuel injection valve needle (2,22) is partially circumscribed by a cylindrical support section arranged between the fuel space and the control space and through which the valve needle (2,22) 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 (2,22) is provided with a grooving arranged at least partially at an angle with the center axis of the valve needle (2,22); - the fuel injection unit comprises at least two independently operable fuel injection valve needles (2, 22), 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 (2,22) comprising a first end and a second end, in which the first end of fuel injection valve needle (2,22) 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 (2,22) is arranged to extend into the control space; - the fuel injection valve needle (2,22) is partially circumscribed by a cylindrical support section arranged between the fuel space and the control space and through which the valve needle (2,22) 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 (2,22) is provided with a grooving arranged at least partially at an angle with the center axis of the valve needle (2,22); - the fuel injection unit comprises at least two independently operable fuel injection valve needles (2, 22), 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.