2005 Audi S4 vs. 2004 BMW 645
To start off, 2005 Audi S4 is newer by 1 year(s). Which means there will be less support and parts availability for 2004 BMW 645. In addition, the cost of maintenance, including insurance, on 2004 BMW 645 would be higher. At 4,398 cc (8 cylinders), 2004 BMW 645 is equipped with a bigger engine. In terms of performance, 2005 Audi S4 (340 HP @ 6200 RPM) has 12 more horse power than 2004 BMW 645. (328 HP @ 6100 RPM). In normal driving conditions, 2005 Audi S4 should accelerate faster than 2004 BMW 645. With that said, vehicle weight also plays an important factor in acceleration. 2004 BMW 645 weights approximately 33 kg more than 2005 Audi S4.
Let's talk about torque, 2004 BMW 645 (451 Nm) has 41 more torque (in Nm) than 2005 Audi S4. (410 Nm). This means 2004 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 | 2004 BMW 645 | |
| Make | Audi | BMW |
| Model | S4 | 645 |
| Year Released | 2005 | 2004 |
| Body Type | Sedan | Convertible |
| 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 | 6200 RPM | 6100 RPM |
| Torque | 410 Nm | 451 Nm |
| Engine Bore Size | 85 mm | 92 mm |
| Engine Stroke Size | 93 mm | 82.7 mm |
| Number of Seats | 5 seats | 4 seats |
| Number of Doors | 4 doors | 2 doors |
| Vehicle Weight | 1782 kg | 1815 kg |
| Vehicle Length | 4550 mm | 4830 mm |
| Vehicle Width | 1770 mm | 1860 mm |
| Vehicle Height | 1430 mm | 1380 mm |
| Wheelbase Size | 2760 mm | 2790 mm |
| Fuel Consumption Overall | 11.8 L/100km | 12.8 L/100km |
| Fuel Tank Capacity | 66 L | 70 L |
