2006 Audi A4 vs. 2004 BMW 645
To start off, 2006 Audi A4 is newer by 2 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 121 more horse power than 2006 Audi A4. (201 HP @ 5100 RPM) In normal driving conditions, 2004 BMW 645 should accelerate faster than 2006 Audi A4. With that said, vehicle weight also plays an important factor in acceleration. 2004 BMW 645 weights approximately 205 kg more than 2006 Audi A4. So despite on having greater horse power, its additional weight may have an impact towards its acceleration in comparison.
Because 2004 BMW 645 is rear wheel drive (RWD), it offers better handling in dry conditions; in addition, if you are looking to drift, it will be much easier to do with 2004 BMW 645. However, in wet, icy, snow, or gravel driving conditions, 2006 Audi A4, being front wheel drive (FWD), will offer much better control with better grip. 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, 2004 BMW 645 (447 Nm) has 166 more torque (in Nm) than 2006 Audi A4. (281 Nm). This means 2004 BMW 645 will have an easier job in driving up hills or pulling heavy equipment than 2006 Audi A4.
Compare all specifications:
| 2006 Audi A4 | 2004 BMW 645 | |
| Make | Audi | BMW |
| Model | A4 | 645 |
| Year Released | 2006 | 2004 |
| Body Type | Sedan | Coupe |
| Engine Position | Front | Front |
| Engine Size | 1983 cc | 4392 cc |
| Engine Cylinders | 4 cylinders | 8 cylinders |
| Engine Type | in-line | V |
| Valves per Cylinder | 4 valves | 4 valves |
| Horse Power | 201 HP | 322 HP |
| Engine RPM | 5100 RPM | 7400 RPM |
| Torque | 281 Nm | 447 Nm |
| Engine Bore Size | 82.5 mm | 92 mm |
| Engine Stroke Size | 92.8 mm | 83 mm |
| Engine Compression Ratio | 10.5:1 | 10.5:1 |
| Drive Type | Front | Rear |
| Number of Seats | 5 seats | 4 seats |
| Number of Doors | 4 doors | 2 doors |
| Vehicle Weight | 1510 kg | 1715 kg |
| Vehicle Length | 4590 mm | 4840 mm |
| Vehicle Width | 1780 mm | 1860 mm |
| Vehicle Height | 1430 mm | 1380 mm |
| Wheelbase Size | 2660 mm | 2790 mm |
| Fuel Consumption | 7.8 L/100km | 9.4 L/100km |
| Fuel Consumption City | 10.7 L/100km | 13.8 L/100km |
| Fuel Consumption Overall | 9.4 L/100km | 11.8 L/100km |
| Fuel Tank Capacity | 63 L | 70 L |
