2005 BMW 645 vs. 2008 Opel Signum
To start off, 2008 Opel Signum is newer by 3 year(s). Which means there will be less support and parts availability for 2005 BMW 645. In addition, the cost of maintenance, including insurance, on 2005 BMW 645 would be higher. At 4,392 cc (8 cylinders), 2005 BMW 645 is equipped with a bigger engine. In terms of performance, 2005 BMW 645 (326 HP @ 6100 RPM) has 173 more horse power than 2008 Opel Signum. (153 HP @ 5600 RPM). In normal driving conditions, 2005 BMW 645 should accelerate faster than 2008 Opel Signum. With that said, vehicle weight also plays an important factor in acceleration. 2005 BMW 645 weights approximately 360 kg more than 2008 Opel Signum. So despite on having greater horse power, its additional weight may have an impact towards its acceleration in comparison.
Because 2005 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 2005 BMW 645. However, in wet, icy, snow, or gravel driving conditions, 2008 Opel Signum, 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, 2005 BMW 645 (447 Nm @ 3600 RPM) has 227 more torque (in Nm) than 2008 Opel Signum. (220 Nm @ 3800 RPM). This means 2005 BMW 645 will have an easier job in driving up hills or pulling heavy equipment than 2008 Opel Signum.
Compare all specifications:
| 2005 BMW 645 | 2008 Opel Signum | |
| Make | BMW | Opel |
| Model | 645 | Signum |
| Year Released | 2005 | 2008 |
| Body Type | Convertible | Hatchback |
| Engine Position | Front | Front |
| Engine Size | 4392 cc | 2197 cc |
| Engine Cylinders | 8 cylinders | 4 cylinders |
| Engine Type | V | in-line |
| Valves per Cylinder | 4 valves | 4 valves |
| Horse Power | 326 HP | 153 HP |
| Engine RPM | 6100 RPM | 5600 RPM |
| Torque | 447 Nm | 220 Nm |
| Torque RPM | 3600 RPM | 3800 RPM |
| Engine Bore Size | 92 mm | 86 mm |
| Engine Stroke Size | 83 mm | 94.6 mm |
| Engine Compression Ratio | 10.5:1 | 12.0:1 |
| Fuel Type | Gasoline - Premium | Gasoline - Premium |
| Top Speed | 250 km/hour | 211 km/hour |
| Acceleration 0-100mph | 6.1 seconds | 9.8 seconds |
| Drive Type | Rear | Front |
| Transmission Type | Manual | Manual |
| Number of Seats | 4 seats | 5 seats |
| Number of Doors | 2 doors | 5 doors |
| Vehicle Weight | 1895 kg | 1535 kg |
| Vehicle Length | 4830 mm | 4640 mm |
| Vehicle Width | 1860 mm | 1800 mm |
| Vehicle Height | 1380 mm | 1470 mm |
| Wheelbase Size | 2890 mm | 2840 mm |
| Fuel Consumption Highway | 10.2 L/100km | 7.2 L/100km |
| Fuel Consumption City | 15.7 L/100km | 12.4 L/100km |
| Fuel Consumption Overall | 12.8 L/100km | 8.1 L/100km |
| Fuel Tank Capacity | 70 L | 60 L |
