2005 Audi S4 vs. 2006 BMW 645
To start off, 2006 BMW 645 is newer by 1 year(s). Which means there will be less support and parts availability for 2005 Audi S4. In addition, the cost of maintenance, including insurance, on 2005 Audi S4 would be higher. At 4,398 cc (8 cylinders), 2006 BMW 645 is equipped with a bigger engine. In terms of performance, 2005 Audi S4 (340 HP @ 4000 RPM) has 12 more horse power than 2006 BMW 645. (328 HP @ 6100 RPM). In normal driving conditions, 2005 Audi S4 should accelerate faster than 2006 BMW 645. With that said, vehicle weight also plays an important factor in acceleration. 2006 BMW 645 weights approximately 40 kg more than 2005 Audi S4.
Let's talk about torque, 2006 BMW 645 (450 Nm) has 40 more torque (in Nm) than 2005 Audi S4. (410 Nm). This means 2006 BMW 645 will have an easier job in driving up hills or pulling heavy equipment than 2005 Audi S4.
Compare all specifications:
| 2005 Audi S4 | 2006 BMW 645 | |
| Make | Audi | BMW |
| Model | S4 | 645 |
| Year Released | 2005 | 2006 |
| Body Type | Sedan | Coupe |
| Engine Position | Front | Front |
| Engine Size | 4163 cc | 4398 cc |
| Engine Cylinders | 8 cylinders | 8 cylinders |
| Engine Type | V | V |
| Valves per Cylinder | 5 valves | 4 valves |
| Horse Power | 340 HP | 328 HP |
| Engine RPM | 4000 RPM | 6100 RPM |
| Torque | 410 Nm | 450 Nm |
| Engine Compression Ratio | 11.0:1 | 10.0:1 |
| Number of Seats | 5 seats | 4 seats |
| Number of Doors | 4 doors | 2 doors |
| Vehicle Weight | 1770 kg | 1810 kg |
| Vehicle Length | 4550 mm | 4830 mm |
| Vehicle Width | 1770 mm | 1860 mm |
| Vehicle Height | 1430 mm | 1380 mm |
| Wheelbase Size | 2770 mm | 2790 mm |
| Fuel Consumption Overall | 11.8 L/100km | 13.3 L/100km |
| Fuel Tank Capacity | 66 L | 70 L |
