1981 BMW 520 vs. 1991 Ford Sierra
To start off, 1991 Ford Sierra is newer by 10 year(s). Which means there will be less support and parts availability for 1981 BMW 520. In addition, the cost of maintenance, including insurance, on 1981 BMW 520 would be higher. At 1,991 cc (6 cylinders), 1981 BMW 520 is equipped with a bigger engine. In terms of performance, 1981 BMW 520 (123 HP @ 5800 RPM) has 48 more horse power than 1991 Ford Sierra. (75 HP @ 4500 RPM). In normal driving conditions, 1981 BMW 520 should accelerate faster than 1991 Ford Sierra. With that said, vehicle weight also plays an important factor in acceleration. 1981 BMW 520 weights approximately 75 kg more than 1991 Ford Sierra. So despite on having greater horse power, its additional weight may have an impact towards its acceleration in comparison.
Let's talk about torque, 1981 BMW 520 (170 Nm @ 4000 RPM) has 18 more torque (in Nm) than 1991 Ford Sierra. (152 Nm @ 2200 RPM). This means 1981 BMW 520 will have an easier job in driving up hills or pulling heavy equipment than 1991 Ford Sierra.
Compare all specifications:
| 1981 BMW 520 | 1991 Ford Sierra | |
| Make | BMW | Ford |
| Model | 520 | Sierra |
| Year Released | 1981 | 1991 |
| Engine Position | Front | Front |
| Engine Size | 1991 cc | 1751 cc |
| Engine Cylinders | 6 cylinders | 4 cylinders |
| Engine Type | in-line | in-line |
| Horse Power | 123 HP | 75 HP |
| Engine RPM | 5800 RPM | 4500 RPM |
| Torque | 170 Nm | 152 Nm |
| Torque RPM | 4000 RPM | 2200 RPM |
| Engine Bore Size | 80 mm | 82.5 mm |
| Engine Stroke Size | 66 mm | 82 mm |
| Engine Compression Ratio | 9.8:1 | 21.5:1 |
| Number of Seats | 5 seats | 5 seats |
| Number of Doors | 4 doors | 4 doors |
| Vehicle Weight | 1220 kg | 1145 kg |
| Vehicle Length | 4630 mm | 4430 mm |
| Vehicle Width | 1710 mm | 1700 mm |
| Vehicle Height | 1430 mm | 1370 mm |
| Wheelbase Size | 2630 mm | 2620 mm |
| Fuel Tank Capacity | 70 L | 60 L |
