2006 BMW Z4 vs. 1991 BMW 730
To start off, 2006 BMW Z4 is newer by 15 year(s). Which means there will be less support and parts availability for 1991 BMW 730. In addition, the cost of maintenance, including insurance, on 1991 BMW 730 would be higher. At 3,246 cc (6 cylinders), 2006 BMW Z4 is equipped with a bigger engine. In terms of performance, 2006 BMW Z4 (338 HP @ 7900 RPM) has 153 more horse power than 1991 BMW 730. (185 HP @ 5800 RPM). In normal driving conditions, 2006 BMW Z4 should accelerate faster than 1991 BMW 730. With that said, vehicle weight also plays an important factor in acceleration. 1991 BMW 730 weights approximately 115 kg more than 2006 BMW Z4.
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, 2006 BMW Z4 (365 Nm @ 4900 RPM) has 105 more torque (in Nm) than 1991 BMW 730. (260 Nm @ 4000 RPM). This means 2006 BMW Z4 will have an easier job in driving up hills or pulling heavy equipment than 1991 BMW 730.
Compare all specifications:
| 2006 BMW Z4 | 1991 BMW 730 | |
| Make | BMW | BMW |
| Model | Z4 | 730 |
| Year Released | 2006 | 1991 |
| Body Type | Convertible | Sedan |
| Engine Position | Front | Front |
| Engine Size | 3246 cc | 2986 cc |
| Engine Cylinders | 6 cylinders | 6 cylinders |
| Engine Type | in-line | in-line |
| Horse Power | 338 HP | 185 HP |
| Engine RPM | 7900 RPM | 5800 RPM |
| Torque | 365 Nm | 260 Nm |
| Torque RPM | 4900 RPM | 4000 RPM |
| Engine Compression Ratio | 11.5:1 | 9.0:1 |
| Fuel Type | Gasoline - Premium | Gasoline |
| Drive Type | Rear | Rear |
| Transmission Type | Manual | Manual |
| Number of Seats | 2 seats | 5 seats |
| Number of Doors | 2 doors | 4 doors |
| Vehicle Weight | 1485 kg | 1600 kg |
| Vehicle Length | 4120 mm | 4920 mm |
| Vehicle Width | 1790 mm | 1850 mm |
| Vehicle Height | 1310 mm | 1420 mm |
| Wheelbase Size | 2500 mm | 2840 mm |
| Fuel Tank Capacity | 55 L | 90 L |
