The Z engine is compared with common TDI engine in the table below. “+” means, that the Z engine is better in the area in question.
| Turbo diesel, 4 cylinders, 4-stroke, 2 camshafts, 4 x 4 valves | Z engine, 2 cylinders, 2-stroke, turbo, 2 camshafts, 2 x 4 valves | |
| + | Higher manufacturing costs | 25 % lower manufacturing costs |
| + | Larger size | 25 % smaller size |
| + | Heavier | 25 % lighter |
| + | Higher fuel consumption | 10-30 % smaller fuel consumption |
| + | Particle filter | No need for particle filter |
| + | NOx -catalyzer | No need for NOx -catalyzer |
| + | 4 cylinders | 2 cylinders |
| - | No compressor cylinder | Compressor cylinder |
| + | Higher fuel injection pressure | Lower fuel injection pressure (~500 bar, Z combustion) |
| + | Expensive fuel injector | Low cost fuel injector (Z combustion) |
| + | External EGR | Internal EGR |
| + | EGR -cooler (corrosion) | Pressurized air cooler |
| + | EGR -valve (expensive) | Pressure valve |
| + | Hotter exhaust gas | Cooler exhaust gas |
| 0 | Turbocharger | Turbocharger |
| 0 | 2 camshafts | 2 camshafts, 1st order balancing |
| 0 | 2nd order balancing | 2nd order balancing |
| + | Slower warm up. | Faster warm up because of the lower mass. |