With a good deal more power, the BMW 650i has put new heart into the German maker's coupe, but looks exactly like the previous model. It doesn't compete with the 500 bhp M6, but offers a very high level of performance and refinement – and even more electronics are in control.
Overall, you get a smooth coupe or convertible but a few odd lines, particularly around the tail. Unless you're a fresh air fiend, I recommend the coupe because it weighs 462 lb ( 210 kg) less than the convertible – that makes the convertible a real heavyweight. Mostly, the BMW 650i coupe looks better too. Also, the aerodynamics are better, with a Cd of 0.30.
new engine develops 367 bhp – up 12%
The BMW 650i is a brilliant car, powered initially by a new 4.8 liter V-8, which comes with variable valve timing and lift in the shape of BMW Valvetronic system. It is an all-aluminum unit developing 367 bhp at 6,300 rpm. Maximum torque of 360 lb ft (490 Nm) is produced at 3,400 rpm, but thanks to the variable valve timing, the engine has masses of torque at almost all speeds – you'll get more than 330 lb ft (450 Nm) between 2,000 and 5,500 rpm, and at higher speeds the engine is singing its way to the limiter at a great rate of knots.
The extra power has sharpened the car a lot, shaving the 0-60 mph time down to about 5.2 seconds, a good deal faster than Jaguar's new lightweight XK in naturally aspirated form.
Three gearboxes on offer
There is the choice of three gearboxes: a six-speed manual, a six-speed Tiptronic or the six-speed SMG sequential box. The SMG is basically a manual gearbox which has a conventional gear lever which the driver can use to push forward or backward to shift. You can also shift by paddles on the steering wheel —these paddles are now the way to change gear among sporty drivers.
However, sequential boxes can be jerky particularly when you're not hurrying, so with this much power available, the Tiptronic is a good choice for all but the sportiest of driving.
Suspension of the 645Ci is BMW's modified version of MacPherson struts at the front, and a multi-link system at the rear. All the components are almost all made from aluminum to save weight, and the front suspension has double joints to improve geometry when cornering, and anti-dive on braking.
At the rear, the multi-link system, which is carried on a sub-frame with the axle gears, also reduces squat on hard acceleration.
Active Steering and Dynamic Drive option
BMW's active steering is now available on most models, including the 650i. It has an extra electric motor driving through an epicyclic gear set to the steering column, so that the ratio is varied to suit conditions much more than is possible with other systems. At low speeds, such as when parking, very little lock turns the car through 90 degrees, but as the speed increases, so the degree of assistance is reduced, and the steering becomes less direct.
At some speeds, active steering does have an odd feel as it alters the ratio while you are turning, and you certainly need to get used to it. It also has an unusual and controversial feature. If it detects a tail slide which needs correcting, it will apply a little opposite lock. BMW says it does this faster than you and I can – and I believe them – but what happens when you apply the opposite lock a bit later, I don't know as I haven't tried that!
DSC+ stability control
Electronics are also used to improve cornering, and prevent the wheels spinning on muddy or gravelly surfaces. This is based on ABS and traction control, but includes several systems all aimed at improving cornering speed and safety, which BMW has been improving steadily over the past 5 years with previous versions of Dynamic Stability Control (DSC). This advanced technology allows high speed cornering with safety. The latest system is DSC+ which has various extra features including shortening the stopping distance in emergency as it primes brake system, and wiping the discs from time to time in the rain.
Almost no roll on corners
New to the 645i, and continued in the 650i is the option of Dynamic Drive, which reduces roll during cornering while improving ride comfort. This is similar to the system Citroen introduced in Europe some years ago, but more refined. There are front and rear active anti-roll bars instead of the normal plain steel bars. Each has a two-piece anti-roll bar with an electric motor.
When going straight ahead, the two parts of the anti-roll bar are unconnected, so the ride comfort is improved, as the anti-roll do not make the suspension harder. When cornering, the motors activate the anti-roll bars, so body roll is cut by 80%, which is much more than with ordinary anti-roll bars.
Alternatively, there is the Sport pack, which has stiffer suspension, and which also controls roll pretty well.
What does it all add up to? Elegance and refinement, with very fast and flat cornering, and agile steering. Quite a car, even if it is large and not the most elegant BMW built.
Driving impressions
A brief drive on quiet roads showed that the BMW 650i is very quick indeed, and handles well, with masses of cornering power. I drove a coupe with Tiptronic gearbox, and the first wake-up call was when I floored the throttle, and saw 80 mph come up in no time at all. It accelerated quickly, the shifts being very smooth, with little noise or fuss.
I discovered that at all speeds, the engine has very fast response, and has plenty of power, particularly when coupled to the responsive six-speed Tiptronic box. Actually, it has more usable power than quite a few cars that have a higher power output because of the combination of a responsive engine and an automatic with a sporty shift.
The manual over-ride works very well, and is ideal for twisty roads, giving maximum acceleration and the ability to power through corners very quickly. The ratios seem well spaced, giving you plenty of speed in the lower gears, without the need to keep shifting on twisty roads.
The standard steering is well-weighted, and has reasonable feel, while the firm suspension is fairly supple most of the time, and quite hard at low speeds, but not unpleasant. On twisty sections of road, the 650i powers around, with very little roll, responding with the agility of a small car.
This car had the Sport suspension which has firmer springs than normal, but not the Dynamic Drive. Even so, the car cornered surprisingly flat. No wonder it makes such a good basis for the M6. As it is the BMW 650i is a very quick, capable and comfortable car and needless to say, the equipment levels are very high.
