Showing posts with label BMW 750Li. Show all posts
Showing posts with label BMW 750Li. Show all posts

2010 BMW 750i xDrive Preview

Despite the fact the new 7 Series was launched at the beginning of the year, BMW is already set to expand the model range. Toward the end of this year, the new V12-powered 760i will arrive with a new eight-speed automatic transmission.

The better news, at least for us denizens of the Great White North, is the addition of BMW's sophisticated xDrive all-wheel-drive system to the 750i. This is a first for the 7 Series and something that's destined to become very popular because of the ability it adds to an already sure-footed sedan.


Under normal circumstances, xDrive splits the power 40/60 front to rear. The beauty is that because the system monitors a number of different sensors (steering angle, throttle position, yaw and so on) xDrive is proactive, which means it begins to redistribute power before the car loses traction. When travelling at speed, the system relaxes the power split (20/80 front to rear). Conversely, matting the gas sees the system lock the centre differential. This splits the power evenly front to rear and banishes unwanted wheelspin. The 750i's system is as seamless as it is proficient.



Naturally, there's a topflight electronic stability/ dynamic traction control system (DSC with DTC). This electronic overseer not only does the usual understeer/ oversteer correction in conjunction with xDrive (it alters the power split to compensate for any wayward tendencies), it also features something called Performance Control.

This safety extension uses the brakes to physically turn the vehicle into a corner. For example, if the driver encounters understeer in a left-hand bend, the system does two things --it applies the left rear brake, which turns the car into the corner, and it ramps up the power output to counter drag cause by the brake application. The system has three modes -- on, DTC mode and off. The last setting is all but redundant because the DTC mode is so good at what it does. In practice, it reduces the car's natural understeering tendency because it allows the back end to drift out a little before reining things in.

When it comes to the 750i xDrive's driving dynamics, they are superb. Unlike so many large cars, this one does not feel like a yacht. Credit the stiff chassis, dialled-in active suspension and Dynamic Drive Control.

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There are four modes in all. Comfort and normal are self-explanatory. Moving to the sport mode does a number of things. As well as firming both compression and rebound damping, it remaps the transmission so each gear is held a little longer, and it sharpens throttle response. The neat part is the driver can customize the settings through the iDrive system. One can select the suspension and steering facets alone, just the power-train changes or both.

Beyond that is the Sport+ mode. It sharpens everything while cutting back the electronic stability control's intervention point. In this mode, the 7 Series feels surprisingly spry on its P245/45R19 front and P275/40R19 rear tires. Remember, this is a full-bodied and portly sedan that tips the scales at more than 2,100 kilograms.

The xDrive model features the same 4.4-litre twin-turbo V8 as in the regular 750i. This motor is not only sublimely smooth, it packs a hellacious punch when the gas is nailed. The secret boils down to the turbochargers nestled in the vee between the banks. When they spool up to speed, which happens in a hurry, the engine produces 400 horsepower and 450 pound-feet of torque anywhere between 1,800 and 4,500 rpm, which allows the 7 to run to 100 kilometres an hour in approximately 5.5 seconds.

Pushing the new 750i xDrive around BMW's proving grounds in Miramas and through the foothills north of the facility proved the car's dynamic advantages go well beyond the ability to drive all four wheels. In normal mode, the 750i xDrive did understeer on the wet and slippery handling track. However, the softer suspension settings took the sting out of the rough roads encountered on the run through the hills -- this is the setup for someone who's had a long, hard day at the office.

Engaging the Sport+ mode significantly changed the car's driving characteristics. Relaxing the stability control's intervention point and reducing the amount of power going to the front wheels makes the all-wheel-drive 7 feel more like its rear-drive sibling. There was less understeer on the track and it pulled out of a hilly hairpin with more authority. When a spirited drive is the order of the day, this is the right mode.

Adding the ability of xDrive to the usual accoutrement that defines the 750i is a smart move because of the manner in which it all comes together. BMW expects 80% of 7 Series buyers to tick the all-wheel-drive option box when ordering their cars. I would if it was my money on the line.

2009 BMW 750Li: The Best Luxury Sedan

The 400-horsepower BMW 750Li has rear-wheel steering. Below 40 miles per hour, the rear wheels can turn as much as 3 degrees opposite the direction of the front wheels, thereby reducing the big car’s turning radius.

I'm quite certain that somewhere right now, emotionally shattered BMW technicians are gathering in a church basement for a support group, huddled around the cookies and the coffee urn, their hands fairly vibrating with frustration. For as well deserved as is the title Ultimate Driving Machine, BMWs also have earned the reputation as the Ultimate Hangar Queen, taking up residence in dealership service bays and sending mechanics over the crumbling edge of insanity. Hello -- sob! -- my name is Dieter and I'm a BMW tech . . . . Hello, Dieter, keep comin' back. . . .

Yes, BMWs have middling initial quality and distinctly less-than-middling reliability -- so sayeth J.D. Power -- but people still buy them and adore them, because they are inarguably spectacular cars. Even the BMWs that I loathe are great cars. The new 135i is uglier than a Radcliffe glee club, but it's also fierce, fervid, delicious, a bottle of Bollinger that's lost its cork.

And then there's this car, the 2009 BMW 750Li, the flagship of BMW's starfleet, which might be -- one hates to draw lines in this particular sand -- the best luxury sedan in the world. Oh, sure, it could be better. It could run on the tears of disgraced CEOs or cure warts of the keister. But as an executive saloon, as a synthesis of power and grace and ease and prestige, the new 7-series demands that we reset our calipers, raise our ceilings and throw out our measuring sticks. There is now a new standard.

And yet, the 750Li boldly/daringly/foolishly leverages its greatness on the fulcrum of one of the company's perennial weaknesses: electronics. This car comprises a blazing amour fou of control modules, sensors, microcontrollers, solenoids and mechatronic actuators, all wired together with the CAN-bus network from hell.

Our fully optioned $110,170 test car provides an acute example. Among the systems: night vision display with enhanced pedestrian detection; active blind-spot detection; lane-departure warning; park-distance control; head-up display; adaptive headlights with high-beam "assistant"; three high-resolution cameras on the rear deck lid and front fenders.

Of course, there's an 80-gigabyte, hard-drive-based navigation system, satellite radio and premium audio system; and a completely redesigned version of the multifunction iDrive controller (the previous system was nicknamed "iQuit").

My favorite? The integral active steering system, which is to say, rear-wheel steering. Below 40 miles per hour, the rear wheels can turn as much as 3 degrees opposite the direction of the front wheels, thereby reducing the big car's turning radius. Great for parking and tight city traffic. Above 40 mph, the wheels turn in phase with the front wheels to increase handling responsiveness, cornering and agility.

Does integral active steering perform as advertised? Has Hasselhoff had work? This car runs like mighty winged Pegasus, carving mountain roads and dicing switchbacks as if it were an M3 with a pituitary problem. No big car has ever had so much rail-to-rail slaloming agility, such effortless composure at the limit. It's uncanny, it's eerie, it's surreal.

Indeed, the effect of all these electronics is to knit together a kind of digitized meta-reality where the surly bonds of physics have slipped a bit, a place where this enormous, heavy sedan can dance like a sports car. Think of it like the world of "The Matrix," inside of which Keanu Reeves can fly, or act.

And so we arrive at the truest portrait of the 750Li: half machine, half machine code; a kinetic sculpture, partly aluminum and steel, partly a stream of zeros and ones. Wonderful, epic, historic.

But can you trust it?
I really don't know. On the one hand, I'm utterly smitten by the technology. I love piloting a leather-lined spaceship with a 20-way adjustable captain's chair with heating/cooling and massage function.

There are moments on the interstate at night -- when the ghostly thermal-imaging night-vision display is on, the head-up display is reading out navigation messages, the lane-departure warning system is gently reminding me to use my turn signals, and all is bathed in serene LED cabin light -- that the 750Li really feels like something that comes after the Automobile.

Still, I'm nagged by doubt. All of these exotic systems, such as the head-up display (Nippon Seiki), lane-change warning (Hella) and night vision (Autoliv) come from suppliers in Japan, Germany and Sweden, respectively. The 750Li is practically the U.N. of Tier 1 suppliers. Considering the state of global comity, a question occurs to me: Can they all get along?

Bear in mind, all of this gear is overlaid on the car's, the brand's already fraught electronics: the e-throttle-equipped 4.4-liter, 400-horsepower, twin-turbocharged V8 with variable valve timing on intake and exhaust cams; the adaptive six-speed ZF transmission; the adaptive dynamics system, which itself has four distinct modes (Comfort, Normal, Sport and Sport+), which ratchet up performance thresholds for the engine, transmission, brakes, steering and stability control. The braking module governs anti-lock, traction and stability control, brake "drying," brake-fade compensation. . . . It just goes on and on.

What few buyers appreciate is how difficult systems integration is on a car like this. For the BMW 750Li to work, every system and subsystem has to mind-meld with the others in a cold chatter of instant, endless algorithms, faultlessly, every time, forever and ever, amen. No wonder they go buggy.

So when I say the 750Li is the best luxury sedan in the world, imagine a weather-balloon-size asterisk. I guess, as long as it starts, it is.

 
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