1. OEM has a double spring system N1 has a single one. Allegedly both have identical spring rates. Interestingly, the N1 has a small oil hole in the relief piston that is drilled down about 8 mm from the top edge, level with the relief oil channel in the pump housing.
2. The oil pump gears are the biggest difference. The internal gear N1 has 1 cams less (11) than the OEM with 12. This means that the internal volume of the pump gears can be increased by a newly designed shape on the contact surfaces between the external gear and the internal gear. N1 pump wheel is bigger than OEM
3. The standard gears are 0.56 hardness and the N1 0.96 hardness. A clear difference! N1 gears are hardened.
4. Internal channels are all larger and redesigned in the pump housing to increase flow
5. The pump support plate has an additional screw on the N1 (8 screws vs 7 in the standard version). In addition, the support plate is 0.5 mm thicker (6.5 mm for the N1 vs 6 mm for the std.)