M stands for Monster: New M5 promises to be BMW's hottest production sedan ever
By GREG KABLE
Photos by Stan Papior
2006 BMW M5
ON SALE: 2005
BASE PRICE: $80,000 (est.)
POWERTRAIN: 5.0-liter, 500-hp, 369-lb-ft V10; rwd, seven-speed manual
CURB WEIGHT: 3900 pounds (est.)
0 to 60 MPH: 4.7 seconds (est.)
Replacing a landmark car is never easy. When the landmark car has whipped every conceivable rival in convincing fashion in its lifetime, the job is even harder. And that's the task the new BMW M5 faces. Its iconic predecessor set the sport sedan standard for six years, until it ceased production late last year.
Rather than rest on its laurels and simply refine a winning package, BMW's M division has dug deep into its development coffers to raise the four-door stakes-again.
The concept behind the new M5 is the same as always: "To blend an unobtrusive appearance with a high-performance engine and premium levels of sedan car comfort." But this execution is different, more courageous than any in the model's 20-year history.
Everything you need to know about Munich's new 155-mph four-door flyer is summed up in the sophistication of the monster engine behind the signature kidney grille. This F1-inspired V10 signals the M division's newfound determination to not only demolish its rivals on driving finesse, but to do so with outright grunt as well.
By replacing the previous model's 4.9-liter V8 with a 5.0-liter V10, BMW elevates the Performance potential to a higher plane. Displacement has barely changed, but output has shot up by 100 hp to a tantalizing 500 hp-and in the process, that magic 100-hp-per-liter that has long been an M division forte has been achieved. Torque is up, too, with 369 lb-ft concentrated in the first half of the rev range.
The V10's fundamentals are much like the old V8's: 90-degree architecture, aluminum construction, four valves per cylinder. But numer-ous refinements have been made to the internal structure, variable valve timing (Double Vanos in BMW-speak), electronically controlled individual throttle butterflies and in-house-develop-ed engine management system designed to sharpen throttle response.
Rather than resort to forced induction like rivals AMG and Audi Sport do with the E55 and RS6, respectively, BMW engineers rely on a heavy dose of revs to achieve the 25 percent increase in power. If rumors circulating at the M5's unveiling at Geneva in March hold true, the new engine will rev close to 8500 rpm in production trim.
M division development boss Gerhard Richter masterminded the V10, which is also earmarked for the M6 due out next year. "It really is quite special," Richter says. "There are some trick internals that let it rev quite high. You won't be disappointed!"
Proof of this is reflected in the acceleration. With a projected 0-to-60-mph time around 4.7 seconds, the new M5 is a full 0.6 second faster than its predecessor. Even more impressive is its 0-to-120-mph split, which is put at a sports car-like 12.7 seconds. Like all M cars, top speed is limited to 155 mph, although Richter hints it would be capable of something closer to 185 mph.
A new seven-speed version of BMW's sequential manual gearbox, based on the six-speed the M3 uses, will be offered as an alternative to a more traditional seven-speed manual. SMG actu-ation is via twin paddles fixed to the steering wheel or a stubby, chromed-topped gear lever. As in the M3, the driver can choose from among 11 different programs-five automatic modes, six manual ones-to alter the gear-change characteristics.
The aggressive stance of the BMW M5 concept car unveiled in Geneva was honed in the wind tunnel to take full advantage of the V10 powerplant under the Hood
. The chromed gills in the front Fender
appear to be a new M car signature.
The M5's substantial power is channeled through a beefed-up version of BMW's limited-slip M differential. It measures the difference in wheel rotations left to right, and apportions power via an electronically controlled clutch, depend-- ing on traction levels. The trick rear axle is allied to a fourth-generation version of BMW's Dynamic Stability Control and Traction system.
Underneath is a reworked rear-wheel-drive 5 Series platform beefed up with components taken from the flagship 7 Series, including parts of its rear axle and brakes. Dry-sump lubri-cation allows BMW to set the engine aftward and closer to the ground than the standard inline six and V8 engines offered in the 5 Series. Weight distribution is 50/50. The entire load-bearing structure forward of the A-pillars is made from a mix of aluminum and lightweight high-tensile steel. Still, BMW remains tight-lipped on actual weight until closer to the production version's unveiling at the Paris motor show in September. Our estimates put it around 3900 pounds.
BMW used the demanding N1/4rburgring Nordschleife to refine the car's MacPherson strut front and multilink rear suspension. Richter won't give specifics, but he says the geometry has been revised with track lengths providing a "substantially larger footprint than the 5 Series." A lot of develop-- ment work also has been focus-ed on stiffening the subframes to which the suspension is attached and minimizing unsprung weight through a "heavier concentration of aluminum components."
Given the M division's traditional attention to detail, it seems safe to assume the new M5's steering will be more direct than ever. The new car will use a modified Active Steering system that is optional on the 5 Series. Expect loads of feedback, too, for there is plenty of rubber in contact with the road. The lightweight 10-spoke alloys are shod with generously sized 225/40ZR front and 285/35ZR rear Michelin Pilot Sport tires.
We can't yet know whether the new M5 will retain the reputation for sport sedan greatness, but we can be consoled in knowing it at least looks the part. As these pictures reveal, the new car looks every bit as determined as its mechanical specifications suggest.
While changes from the standard 5 Series are subtle, they have all been finely honed in the wind tunnel and are entirely functional. There is no pretense, just parts that get the job done. There is a deep air dam with three cooling ducts, generously flared wheel arches, chunkier side sills and a complex rear bumper with a central diffuser designed to draw hot air away from the differential.
In what is likely to become an M car signature, this 5 sports chromed gills behind its front wheel arches and four chromed tailpipes poking out in pairs from each side at the rear. Also, 19-inch alloy wheels-8.5 inches wide at the front, 9.5 at the rear.
If Richter can be believed, then M division's chief designer Ulf Weidhase has done his job well. "It's got real presence on the road," he enthuses. "When we were out testing with final prototypes on public roads it was instantly spotted as being more than a normal 5 Series."
When the new M5 reaches North American showrooms sometime next year, it is almost certainly going to cost more than the car it replaces. With the price premium will come higher levels of technology, added Performance, and as luxurious an interior as any in the BMW lineup. The new M5 might be more powerful than ever, but it's apparent M car buyers still enjoy their comfort, too.