| Type | Number of cylinders | Bore x stroke in mm | Displacement in cm³ | hp | Construction period |
|---|---|---|---|---|---|
| Neckarsulm 1.5 hp | 1 | – | – | 1.5 | 1901 – 1903 |
| Neckarsulm 2.5 hp | 1 | 75 x 75 | 329 | 2.5 | 1903 – 1905 |
| Neckarsulm 1.25 hp | 1 | 62 x 70 | 310 | 1.25 | 1907 |
| Neckarsulm 4 hp | 1 | 64 x 75 | 554 | 4 | 1909 |
| Neckarsulm 2.5 hp | 2 | 52 x 74 | 315 | 2.5 | 1909 |
| Neckarsulm 6 hp | 2 | 75 x 90 | 795 | 6 | 1909 – 1911 |
| NSU 2.5 hp | 1 | 73 x 78 | 326 | 2.5 | 1913 |
| NSU 3.5 hp | 2 | 63 x 80 | 495 | 3.5 | 1913 – 1921 |
| NSU 6.5 hp | 2 | 75 x 94 | 830 | 6.5 | 1913 – 1921 |