2006 Audi S4 vs. 2008 BMW 645
To start off, 2008 BMW 645 is newer by 2 year(s). Which means there will be less support and parts availability for 2006 Audi S4. In addition, the cost of maintenance, including insurance, on 2006 Audi S4 would be higher. At 4,398 cc (8 cylinders), 2008 BMW 645 is equipped with a bigger engine. In terms of performance, 2006 Audi S4 (339 HP @ 7000 RPM) has 11 more horse power than 2008 BMW 645. (328 HP @ 6100 RPM). In normal driving conditions, 2006 Audi S4 should accelerate faster than 2008 BMW 645. With that said, vehicle weight also plays an important factor in acceleration. 2008 BMW 645 weights approximately 540 kg more than 2006 Audi S4.
Because 2006 Audi S4 is four wheel drive (4WD), it will have significant more traction and grip than 2008 BMW 645. In wet, icy, snow, or gravel driving conditions, 2006 Audi S4 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, 2008 BMW 645 (450 Nm @ 3600 RPM) has 39 more torque (in Nm) than 2006 Audi S4. (411 Nm @ 3500 RPM). This means 2008 BMW 645 will have an easier job in driving up hills or pulling heavy equipment than 2006 Audi S4.
Compare all specifications:
| 2006 Audi S4 | 2008 BMW 645 | |
| Make | Audi | BMW |
| Model | S4 | 645 |
| Year Released | 2006 | 2008 |
| Body Type | Convertible | 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 | 339 HP | 328 HP |
| Engine RPM | 7000 RPM | 6100 RPM |
| Torque | 411 Nm | 450 Nm |
| Torque RPM | 3500 RPM | 3600 RPM |
| Engine Bore Size | 84.5 mm | 92 mm |
| Engine Stroke Size | 92.8 mm | 82.7 mm |
| Fuel Type | Gasoline - Premium | Gasoline - Premium |
| Top Speed | 250 km/hour | 250 km/hour |
| Acceleration 0-100mph | 5.9 seconds | 6.4 seconds |
| Drive Type | 4WD | Rear |
| Transmission Type | Manual | Manual |
| Number of Seats | 4 seats | 4 seats |
| Number of Doors | 2 doors | 2 doors |
| Vehicle Weight | 1275 kg | 1815 kg |
| Vehicle Length | 4580 mm | 4830 mm |
| Vehicle Width | 1790 mm | 1860 mm |
| Vehicle Height | 1450 mm | 1380 mm |
| Wheelbase Size | 2660 mm | 2790 mm |
| Fuel Consumption Overall | 13.8 L/100km | 12.8 L/100km |
| Fuel Tank Capacity | 63 L | 70 L |
