This new BMW looks almost ordinary but hiding beneath the sheet metal is a 500 bhp V-10 with seven-speed gearbox. BMW has a tradition of producing powerful M versions of its cars that look ordinary but aren’t. Well, the new M5 takes that concept further.
It gets a brand new engine designed and developed within BMW M instead of being a modified version of an existing engine. And the new engine is a cracker: a 5.0 liter 500 bhp V-10. Unchecked, the car would do 180-190 mph, but as is current BMW policy, the new car is limited to 155 mph. Jaguar and Mercedes-Benz also limit their cars in this way.
Discreet looks for the driver who wants to surprise people -
This is the car for the man or woman who actually wants a car that looks ordinary, but will blow off almost everything it meets. Pity the M5 is not more of a beauty, but those fairly discreet lines will mean a lot to some people. If they want something a little more sporty they can go for the M6.
From a new engine
The V-10 slots between BMW V8 and V-12s, and in line with thinking at BMW M, it is a very high-revving engine without supercharging – unlike the hottest Jaguar and Mercedes-Benz engines. Aston Martin and Honda are among others who prefer not to supercharge.
BMW M says that the advantage of the high-revving engine without supercharging is that you get the power without excessive torque. It’s true that for most driving, plenty of torque is a good idea, but it brings with it the need for bigger gearboxes and final-drive units, which in turn adds weight and cost.
Under the hood, it’s a very different story…
So we have the birth of fabulous new V-10 engine, being built in small numbers. It's a 90-degree V-10, which means that it won't be quite as smooth as some – in theory, at any rate - but it will fit neatly into an engine compartment designed for V-8s.
BMW says that the 90-degree angle makes for a stiffer block, but the main advantage is that BMW will be able to make a V-8 and V-10 on the same production line – the M Center does not make many engines so this is a big advantage. BMW might want to be able to machine the blocks on machines that can also do V-8s, which have 90 degree angle. There are other advantages, such as more space to fit a complex two-stage inlet manifold between the banks of cylinders.
Maximum power is 507 bhp at 7,750 rpm – a real screamer this – while the maximum torque of 380 lb ft is produced at 6,100 rpm. Boy, you're really going to keep this revving if you want to use all that power, but in return you’ll get the feel of a racing engine. Even when it's just mooching along at 4,000 rpm you can bet this one will produce quite a chunk of power.
4 valves per cylinder and variable valve timing
Needless to say, it has all the features you'd expect in a supercar engine, such as a stiff aluminum block, and narrow 4-valve heads. To let the engine rev, the cylinder bores are much bigger than the stroke – 92 x 75.2 mm. BMW uses its variable valve timing system, and drives the inlet camshafts on each bank by chain, with a gear drive to the exhaust camshaft, a system pioneered by Toyota to save space.
This engine is a beautiful piece of work, built by hand at great cost to compete with the best. To stiffen the cylinder block, the bearing caps are formed in a platform that is bolted all round to the cylinder block. Inserted in the castings are cast iron blocks around the lower half of the bearings.
The cylinder heads are conventional in that they have four valves per cylinder and variable valve timing. They’re not so normal in that the valves are very close together in an almost flat combustion chamber, but this is in line with new trends.
There is a very complex Bosch engine controller, and a butterfly valve in the intake port of each cylinder. The controller can change the angle of each one separately in less than the blink of an eyelid to suit conditions in the engine, and get maximum efficiency.
Sequential 7-speed gearbox
Although this engine is reckoned to offer good torque over 3,500 rpm, BMW knows that it’s a screamer and so will need plenty of gears. The answer: The SMG sequential gearbox, now with seven speeds. It is claimed to be able to shift very quickly – all car companies claim that, it must be said, but BMW does seem to have the edge over the competition.
11 shift patterns
This SMG box is unusual in its shift patterns. The driver can select from a menu of 5 automatic and 6 manual gear shift patterns, which each give slightly different shift patterns according to the driver’s choice. Seems a lot to me…
Big tires, 19 inch wheels
And what about that grip? Should be enough for most of us, with 255/40ZR front and 285/35ZR at the rear, all on 19 inch forged aluminium wheels. Most firms use castings which are not as strong as forgings.
The basic suspension is from the 5 Series, and might be a weak link in the plot, but it has all been modified extensively. Both suspension frames and several components are aluminum, and there are strong anti-roll bars.
The dampers are controlled electronically, and the driver has three settings at his disposal; if that’s not enough choice, he can also select ‘comfort’ or ‘sport’ steering assistance.
Stability control with a difference
There’s plenty more electronics around. Most important is the ultra-sporting DSC (stability control) which allows the driver to use plenty of controllable tail-sliding oversteer without getting into danger. Or that’s what they say.
In fact, the driver has an Mdrive button which allows him or her to set the preferred settings for the SMG box, the electronically controlled dampers and DSC. You just dial your degree of sportiness.
To reduce weight, the front end of the body is made from aluminum. Even so, the car is quite a lump at 4,030 lb until you realise that the Mercedes-Benz SL55 AMG weighs 4,300 lb, and that’s a two-seater. Both cars have similar performance.
Driving impressions
I drove the BMW M5 briefly on fairly busy roads, but found it a disappointment – no doubt it is a different story if you drive along deserted mountains in the Alps.
On normal roads, it is almost impossible to keep the engine in the 5,000 to 8,000 rpm range it needs for real power to be produced. If you don't use these revs, the performance is nothing to write home about.
The firm ride was fine, but the SMG gearbox, while OK when in a hurry in manual was very jerky in auto, and so did not feel the right box for a car like the M5.
