2009 Audi A4 vs. 2004 BMW 645
To start off, 2009 Audi A4 is newer by 5 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 4,392 cc (8 cylinders), 2004 BMW 645 is equipped with a bigger engine. In terms of performance, 2004 BMW 645 (322 HP @ 7400 RPM) has 100 more horse power than 2009 Audi A4. (222 HP @ 4000 RPM) In normal driving conditions, 2004 BMW 645 should accelerate faster than 2009 Audi A4. With that said, vehicle weight also plays an important factor in acceleration. 2004 BMW 645 weights approximately 105 kg more than 2009 Audi A4. So despite on having greater horse power, its additional weight may have an impact towards its acceleration in comparison.
Because 2009 Audi A4 is four wheel drive (4WD), it will have significant more traction and grip than 2004 BMW 645. In wet, icy, snow, or gravel driving conditions, 2009 Audi A4 will offer significantly more control. With that said, do keep in mind that many other factors such as speed and the wear on your tires can also have significant impact on traction and control. Let's talk about torque, 2009 Audi A4 (450 Nm) has 3 more torque (in Nm) than 2004 BMW 645. (447 Nm). This means 2009 Audi A4 will have an easier job in driving up hills or pulling heavy equipment than 2004 BMW 645.
Compare all specifications:
| 2009 Audi A4 | 2004 BMW 645 | |
| Make | Audi | BMW |
| Model | A4 | 645 |
| Year Released | 2009 | 2004 |
| Body Type | Sedan | Coupe |
| Engine Position | Front | Front |
| Engine Size | 2965 cc | 4392 cc |
| Engine Cylinders | 6 cylinders | 8 cylinders |
| Engine Type | V | V |
| Valves per Cylinder | 4 valves | 4 valves |
| Horse Power | 222 HP | 322 HP |
| Engine RPM | 4000 RPM | 7400 RPM |
| Torque | 450 Nm | 447 Nm |
| Engine Bore Size | 83 mm | 92 mm |
| Engine Stroke Size | 91.4 mm | 83 mm |
| Engine Compression Ratio | 17.0:1 | 10.5:1 |
| Drive Type | 4WD | Rear |
| Number of Seats | 5 seats | 4 seats |
| Number of Doors | 4 doors | 2 doors |
| Vehicle Weight | 1610 kg | 1715 kg |
| Vehicle Length | 4550 mm | 4840 mm |
| Vehicle Width | 1780 mm | 1860 mm |
| Vehicle Height | 1430 mm | 1380 mm |
| Wheelbase Size | 2660 mm | 2790 mm |
| Fuel Consumption Overall | 7.6 L/100km | 11.8 L/100km |
| Fuel Tank Capacity | 70 L | 70 L |
