1981 BMW 520 vs. 1986 BMW 730
To start off, 1986 BMW 730 is newer by 5 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 2,986 cc (6 cylinders), 1986 BMW 730 is equipped with a bigger engine. In terms of performance, 1986 BMW 730 (197 HP @ 5800 RPM) has 74 more horse power than 1981 BMW 520. (123 HP @ 5800 RPM) In normal driving conditions, 1986 BMW 730 should accelerate faster than 1981 BMW 520. With that said, vehicle weight also plays an important factor in acceleration. 1986 BMW 730 weights approximately 380 kg more than 1981 BMW 520. So despite on having greater horse power, its additional weight may have an impact towards its acceleration in comparison.
Both vehicles are rear wheel drive (RWD) - it offers better handling in dry conditions; in addition, if you are looking to drift, both vehicles do the job better than front wheel drive vehicles. 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, 1986 BMW 730 (275 Nm @ 4000 RPM) has 105 more torque (in Nm) than 1981 BMW 520. (170 Nm @ 4000 RPM). This means 1986 BMW 730 will have an easier job in driving up hills or pulling heavy equipment than 1981 BMW 520.
Compare all specifications:
| 1981 BMW 520 | 1986 BMW 730 | |
| Make | BMW | BMW |
| Model | 520 | 730 |
| Year Released | 1981 | 1986 |
| Body Type | Sedan | Sedan |
| Engine Position | Front | Front |
| Engine Size | 1991 cc | 2986 cc |
| Engine Cylinders | 6 cylinders | 6 cylinders |
| Engine Type | in-line | in-line |
| Horse Power | 123 HP | 197 HP |
| Engine RPM | 5800 RPM | 5800 RPM |
| Torque | 170 Nm | 275 Nm |
| Torque RPM | 4000 RPM | 4000 RPM |
| Engine Bore Size | 80 mm | 89 mm |
| Engine Stroke Size | 66 mm | 80 mm |
| Engine Compression Ratio | 9.8:1 | 9.2:1 |
| Top Speed | 185 km/hour | 225 km/hour |
| Drive Type | Rear | Rear |
| Transmission Type | Manual | Manual |
| Number of Seats | 5 seats | 5 seats |
| Number of Doors | 4 doors | 4 doors |
| Vehicle Weight | 1220 kg | 1600 kg |
| Vehicle Length | 4630 mm | 4920 mm |
| Vehicle Width | 1710 mm | 1850 mm |
| Vehicle Height | 1430 mm | 1420 mm |
| Wheelbase Size | 2630 mm | 2800 mm |
