Right now BMW’s M engineers are hard at work testing and tuning the newest M5, which will debut at the Frankfurt Motor Show in September with 600 horsepower, all-wheel drive, and an eight-speed automatic transmission. When it hits the streets next year it will undoubtedly be the quickest 5 Series of all time.
Until then, it’s this car that wears that crown: the all-wheel-drive 2018 BMW M550i xDrive, which BMW says will shoot to 60 mph in just 3.9 seconds. That’s a full second better than a 540i, but more importantly, it’s also a tick quicker than the previous-generation M5, which was rear-wheel-drive and recently ended production.
The M550i’s impressive performance is the result of applying an age-old hot rodder formula: decrease weight, and increase power and traction. Works every time.
Twin-Turbo V8 Power
In the BMW food chain, M Performance models live a notch above the M Sport Packages that are available on cars like the 335i, but a rung below all-out M machines like the M3 and M5. M Performance first appeared in 2012 and has sold 70,000 cars worldwide, nearly half of which have been in the United States. Surprisingly, Germany is the third-largest market for these cars behind the U.S. and Canada. Today there are seven models available, including the M240i coupe and the M760i.
Until the M5 drops, the 2018 BMW M550i xDrive is the only V8-powered 5 Series available, slotted above the six-cylinder 540i and the base four-cylinder 530i. Under the M550i’s aluminum hood is the same all-aluminum 4.4-liter V8 engine that powered the previous-generation 550i. BMW also carried over its two twin-scroll turbochargers, direct injection, Valvetronic variable valve lift system and Double-VANOS variable camshaft timing control.
Despite the familiar hardware, power is up, from 445 hp to 456 hp at 5,500 rpm. That’s 121 hp more than you get from the twin-turbo six-cylinder in a 540i, but it’s about 100 hp shy of the previous generation M5. The torque rating, 480 lb-ft of torque at just 1,800 rpm, is unchanged.
The M550i is also more than 100 lbs lighter than last year’s rear-wheel-drive M5, despite its standard xDrive all-wheel drive system. BMW’s engineers tell me the system has been tuned specifically for this sedan, though they’re unfortunately keeping the torque-splits top secret. All they’ll say is that the system splits power among all four wheels as the situation demands, intelligently and with a rear-wheel bias.
Those engineers have also equipped the M550i with Launch Control. It allows you to rev the engine to 3,000 rpm, which is the stall speed of the torque converter, while holding the car in place with the brake. When your left foot dumps the brake pedal, the fun begins.
With zero wheelspin the M550i pins me to the leather through the V8’s entire rev range and at 6,500 rpm, right on the tachometer’s redline, the ZF-supplied eight-speed delivers a firm upshift to second. Sixty mph comes quickly, and at full throttle, the transmission, which has also been tuned specifically for this model, clicks off positive gear changes every few seconds. One hundred mph comes and goes with third gear.
We’re on a deserted stretch of two-lane outside Munich so I decide to keep my foot down. At 125 mph in fifth gear, the M550i is still pulling. Hard. And at over 135 mph, the transmission grabs sixth gear. The M550i is governed to 155 mph, but I lift at 150 mph, where the sedan continues to feel locked in. Unlimited on its optional 20-inch Michelin Pilot Super Sports high-performance summer tires (19-inch run flats are standard), the M550i xDrive can reportedly reach 180 mph.
Seemingly Endless Traction
For the upcoming twisties, I push the button on the console and engage Sport+ mode. It firms up the sedan’s suspension, adds weight to its steering and sensitizes its throttle response. The Steptronic eight-speed transmission also wakes up, holding gears longer and delivering even firmer gear changes. Use the paddle shifters and it matches revs on the downshifts.
Sport+ also cranks up the V8’s voice. The M Sport’s exhaust system is unique to this model and includes a throttle valve for more sound. And it sounds good. It’s not so loud to be rude, but it’s a proper V8 soundtrack, like a small-block with a lumpy cam. BMW also continues to pump the V8’s roar into the cabin through the audio system.
The adaptive M Sport suspension is also unique to the M550i, which sits 10 millimeters lower than a 540i and has active roll stabilization. Body roll is minimal, even during hard cornering, but there’s just enough to give you a little feedback. The ride is comfortable, even in Sport+ mode.
Traction seems infinite. And to my surprise, the sedan feels like it’s rear-wheel-drive. There’s no indication in its feel or behavior that it’s also being driven by its front tires. It’s just got a kung fu grip on the road and makes you look like a phenom behind the wheel.
Also impressive are the M Sport brakes, which are dressed with M-badged blue calipers. They’re strong and offer enough feel and a firm pedal. Although there could be more steering feel, there’s enough to satisfy; however, some may think the effort is unnecessarily heavy in Sport+.
In the default Comfort mode, the M550i feels like a 7 Series — more luxurious and relaxed. The ride is plush and the engine, although no less potent, is subdued. Also, the steering is lighter. Even the automatic transmission backs off to deliver silken shifts that are almost undetectable.
A Performance Bargain
Exterior upgrades are mild. The tailpipes are black chrome and there’s a small rear spoiler. BMW is proud of the titanium finish on the front fender vents, mirrors and grille surround, but I like the high-gloss trim around the glass. Inside, BMW adds 20-way power multi-contour seats, blue stitching, an M Sport steering wheel, aluminum pedal trim, illuminated door sills and a sweet set of M design floor mats.
With the all-new M5 still a year away, this is as hot as the 5 Series gets right now. There are more powerful German super sedans out there, like the Mercedes-Benz E63 and Audi RS7, but both cost six figures. And the turbo six-cylinder in the all-wheel-drive Mercedes E43 is too weak to the run with this BMW. Base price is $73,095, including a $995 destination and handling fee — while that’s a big step up from the $52,095 530i, the M550i is still a serious performance bargain in the big banger luxury sedan segment.
That is, at least, until that new M5 arrives.
Photo Credit: © 2017 BMW