2003 BMW 645 vs. 2003 BMW X3
To start off, both 2003 BMW 645 and 2003 BMW X3 were released in the same year (2003). Therefore the support and the availability on parts for both vehicles should be relatively similar. At 4,398 cc (8 cylinders), 2003 BMW 645 is equipped with a bigger engine. In terms of performance, 2003 BMW 645 (310 HP @ 6000 RPM) has 109 more horse power than 2003 BMW X3. (201 HP @ 4000 RPM). In normal driving conditions, 2003 BMW 645 should accelerate faster than 2003 BMW X3. With that said, vehicle weight also plays an important factor in acceleration. 2003 BMW X3 weights approximately 232 kg more than 2003 BMW 645.
Because 2003 BMW X3 is four wheel drive (4WD), it will have significant more traction and grip than 2003 BMW 645. In wet, icy, snow, or gravel driving conditions, 2003 BMW X3 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, 2003 BMW 645 (450 Nm @ 3600 RPM) has 40 more torque (in Nm) than 2003 BMW X3. (410 Nm @ 1500 RPM). This means 2003 BMW 645 will have an easier job in driving up hills or pulling heavy equipment than 2003 BMW X3.
Compare all specifications:
| 2003 BMW 645 | 2003 BMW X3 | |
| Make | BMW | BMW |
| Model | 645 | X3 |
| Year Released | 2003 | 2003 |
| Body Type | Coupe | SUV |
| Engine Position | Front | Front |
| Engine Size | 4398 cc | 2995 cc |
| Engine Cylinders | 8 cylinders | 6 cylinders |
| Engine Type | V | in-line |
| Valves per Cylinder | 4 valves | 4 valves |
| Horse Power | 310 HP | 201 HP |
| Engine RPM | 6000 RPM | 4000 RPM |
| Torque | 450 Nm | 410 Nm |
| Torque RPM | 3600 RPM | 1500 RPM |
| Engine Bore Size | 92 mm | 84 mm |
| Engine Stroke Size | 82.7 mm | 90 mm |
| Engine Compression Ratio | 10.5:1 | 17.0:1 |
| Top Speed | 250 km/hour | 215 km/hour |
| Acceleration 0-100mph | 5.9 seconds | 8.2 seconds |
| Drive Type | Rear | 4WD |
| Transmission Type | Automatic | Automatic |
| Number of Seats | 4 seats | 5 seats |
| Number of Doors | 2 doors | 5 doors |
| Vehicle Weight | 1698 kg | 1930 kg |
| Vehicle Length | 4830 mm | 4570 mm |
| Vehicle Width | 1860 mm | 1860 mm |
| Vehicle Height | 1380 mm | 1680 mm |
| Wheelbase Size | 2790 mm | 2730 mm |
| Fuel Consumption Highway | 8 L/100km | 7.3 L/100km |
| Fuel Consumption City | 16.1 L/100km | 12.1 L/100km |
| Fuel Consumption Overall | 10.9 L/100km | 9.1 L/100km |
| Fuel Tank Capacity | 70 L | 67 L |
