Review: 2012 BMW M6 Convertible

When the “F01” 7-Series arrived in 2008 followed by the “F10” 5-Series in 2009, I saw the writing on the wall; BMW is the new Mercedes. My theory was “proved” after a week with the 2011 335is and 2012 X5M. BMW fans decried my prophesy as blasphemy. I repeated my statement with the 2012 328i and caught the eye of egmCarTech. A Mercedes fan tried to run me over in a parking lot. My colleagues in the press thought I lost my mind. BMW’s media watchers were eerily silent. A month later I was told that BMW would allow me a week in the all-new 2012 M6 Convertible. Would the most expensive M car change my mind or prove the point once and for all?

Exterior

The previous 6 suffered from Chris Bangle’s posterior, a design that was either loved or hated. The new 6 replaces the awkward trunk with curves and creases that seem to please everyone. Despite being lower and wider than a 650i with plenty of unique sheetmetal, the casual observer was unable to tell just how much was altered to create the M6. Who knew the M6 would be a sleeper?

BMW continues to employ a soft top with “classic” 6-Series buttresses on either side of the rear glass, bucking the retractable hardtop trend that’s sweeping the three-pointed star. Aside from the weight benefits, the canvas lid maximizes trunk space, has less impacted on weight balance when the top is down, and most importantly: it operates at speeds up to 25MPH. Compared to the Jaguar XK-R, the M6 is larger and more aggressive. Thankfully, as aggressive as the M6 looks, the profile and details are more elegant than the Mercedes SL63 whose hood vents and trunk spoiler look overdone.

Interior

Inside the changes to the 650i donor car are less dramatic and limited to trim tweaks, lightly restyled seats, new steering wheel, and M-themed shifter. Despite sharing heavily with the plebeian 640i, the cabin is completely at home in a $120,000 luxury coupe with perfect stitched dashboard seams and soft leather everywhere. The only problem I found is the steering column shared with the lesser models. The M6’s airbag is considerably smaller, perfectly round and in the center of a thin three-spoke tiller making the rectangular plastic steering column extremely visible.

During my week with the M6 I acted as a quasi-pace-car driver for a 40-mile charity walk. Four of us spent two 10-hour days driving from one stop to another and hours in the seats getting sunburnt waiting for the walkers to arrive at the next stop. Normally four people jammed into a luxury convertible would be a trying experience, but the M6 was surprisingly comfortable with a useable back seat and supportive front seats. In comparison, the XK’s rear seats are more of a joke than an actual feature, the Mercedes SL doesn’t have any back seats and the Maserati GranCabrio has a similar amount of legroom but awkwardly angled seat backs.

Infotainment & Gadgets

As with most modern BMW products, the M6 comes with BMW’s standard 10.2-inch iDrive system. Unfortunately the minor tweaks made to the new 3-series have not made it to the 6-Series meaning you still have a CD button rather than a media button and the head-up display won’t show you infotainment info. If you want to know more about iDrive, checkout our video on the 2012 650i or click on over to the 650i Coupe and 650i Convertible reviews.

For some reason, BMW’s excellent radar cruise control is not available on the M6, but the rest of the 6-Series’ gadgetry can be added. Our M6 was equipped with the $4,900 “Executive Package” which included full LED headlamps, a heated steering wheel, satellite radio, anti-fatigue front seats, soft-closing doors and BMW’s “apps” package for iDrive. Should your gadget-love know no budget; lane departure warning, blind spot monitoring, all-around video camera and electronic speed limit info can be had for $1,900. Ventilated front seats are a $500 stand alone option, as is the $2,600 night vision system with pedestrian detection. The essential option is the $3,700 Bang & Olufsen sound system. The standard 12-speaker BMW audio system is balanced strangely toward the bright side of normal. If you’re throwing down six figures on your topless weekend car, checking this option box won’t hurt.

iDrive alone puts the M6 at the top of the gadget lover’s list, but let’s compare anyway. With a starting price over $30,000 higher than the M6, the SL63 brings active lane keep assist and radar cruise control to the party but lacks BMW’s night vision, all-around camera, anti-fatigue seats, LED headlamps and, let’s face it, COMAND should be sent out to pasture. The XKR-S looses this battle as well with a $20,000 premium, Jaguar’s aggravating infotainment system, and no gadgets to speak of.

Drivetrain

With CAFE regulations looming, twin-turbo engines are the latest craze for luxury marques and even BMW’s mighty M division has caved. The result is a step backwards and forwards with the bespoke V10 replaced by a modified version of BMW’s 400HP 4.4L twin-turbo V8 (N63). The same basic engine (S63) first debuted under the hood of the 555HP X5M and X6M. For M5 and M6 duty, BMW tweaked the engine by adding Valvetronic, increasing the compression ratio from 9.3:1 to 10:1 and bumping peak boost. The result is a minor increase in horsepower to 560 and a flattening of the power curve from a peak at 6,000RPM, to a plateau from 5,750-7,000. Torque remains steady at a stump-pulling 500lb-ft but broadens to 1,500-5,750RPM. BMW revised the 7-speed “M-DCT” dual clutch transmission from the last M5/M6 and tossed in a new electronic rear differential. While not strictly a drivetrain change, BMW swapped the floating rear subframe for a fixed unit to improve handling and power delivery.

In comparison, the Jaguar XKR-S delivers 550HP and 502lb-ft of twist from its blown 5.0L V8 and the all-new Mercedes SL63 offers your choice of 530HP/557lb-ft or 590HP/664lb-ft from AMG’s new 5.5L twin-turbo V8. Jaguar has continues to stick to the tried-and-true ZF 6-speed automatic while Mercedes continues their love affair with their 7-speed automatic sans torque converter. While each of these transmission types has an advantage, BMW claims their M-DCT transmission shifts in half the time of the competition.

Drive

It often takes a week for me to decide how I like a car. With the M6 it took 50 miles. Why? Because of how well BMW has blended savage acceleration with a soft luxurious ride and comfy seats. The M6 has turned into the ultimate road trip convertible.

Don’t get me wrong, the M6 is a serious performance contender. Bury the throttle and 60 passes in 3.75 seconds followed shortly by a blistering 11.89 second 1/4 mile at an eye popping 123MPH. These numbers are without launch control which, strangely enough, elevated our times by about 3/10ths. Just let the nannies do their thing. The numbers below show the M6 “suffers” slight turbo lag from 0-30. From 30-60, the M6 is a beast taking 0.70 fewer seconds than the XKR-S. By 120MPH the lighter weight of the Jaguar helps it stay right on the heels of the BMW. By the end of the 1/4 mile, the BMW finishes ahead by a car length. My seat time in the SL63 was limited and we weren’t able to get it out on the track, but don’t expect it to be much faster to 60. Despite the serious power advantage, the rear tires are skinnier than the Jag or BMW and traction is king.

2012 Jaguar XKR-S 2012 BMW M6 Convertible

0-30: 1.18 Seconds 1.8 (Thank the turbos for that)

0-60: 3.83 Seconds 3.75 (It’s all about the torque curve baby)

0-120: 11.84 Seconds 11.80 (curb weight means something)

1/4 mile: 12.0 @ 122 MPH 11.89 @ 123 MPH

A word about 0-60 numbers. With high horsepower cars, traction is the limiting factor. Because road surfaces, tires, etc. vary greatly. Our track times cannot be directly compared to other publications as they are not performed on the same surface – nevertheless, we’re all in the same ballpark. We use a 10Hz GPS meter for our testing. According to the manufacturer,accuracy is +/-0.2MPH on 0-60 runs and +/-0.4MPH on 1/4 mile tests. According to our drag-strip verification, the system is within +/-0.3MPH over a 1/4 mile.

Out on the track, the XKR-S and M6 are well matched. While the XKR-S is a bit heavier in the nose and has narrower tires up front, the rear seems to find grip more easily and the steering is more direct and responsive. The English competitor is also 429lb lighter with a firmer suspension, less body roll and an absolutely savage 0-30 time. The M6 counters with lightning fast dual-clutch shifts and seemingly endless mid-range power. For 2012, BMW polished M-DCT’s software and the result is one of the smoothest “robotic manuals” I have ever driven. I’d like to compare it to the Mercedes SPEEDSHIFT transmission in the SL63, but I still have harsh-shift related whiplash from my test drive.

On the broken roads of Northern California, it’s a different story. BMW’s adaptive suspension makes the M6 more composed than the SL or XKR-S on broken pavement, even at higher speeds. It’s not that the Jag or Merc are unrefined by any measure, its that the M6 rides like a 7-Series while it handles like an overweight M3. Thank you modern technology.

The softer ride and number steering mean the M6 is less engaging in the bends. On the flip side, the M6 is a car you can drive every day while the SL63 and XKR-S exact some practical compromises. The M6 is the more comfortable car, it seats four and the monstrous trunk can hold luggage for 3 easily. What the BMW can’t counter is the visceral roar produced by Jag’s 5.0L V8. The M6 in comparison is quiet, some might even say demure.

If you want the best track car, get a GT-R. It will “out everything” the M6 on the track. If you want the best sounding V8 engine, get the XKR-S. If you want the sexiest coupe, get a Maserati. If you want the best all-around sports luxury coupe, look no further than the BMW M6. I admit that after a week with the most expensive M, I am smitten. But have I fallen for the M6 for all the “wrong” reasons? I value the M6’s perfect interior, comfortable seats, electronic do-dads and LED headlamps over straight-line or corner performance. In other-words, I elevate all the values I was raised to associate with Mercedes-Benz. But here in front of me is a BMW that embodies all the luxury I demand yet sacrifices only a smidgin of track performance in the process. I will leave the discussions of branding to more qualified writers, but I will say that nobody I met felt the Mercedes SL brought any more cachet than the M6, despite its price tag. Mercedes has been put on notice. BMW’s M6 reigns alone as the king of the German luxury coupe. AMG: you have been found wanting. (You know, except for that whole SLS thing.)

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BMW provided the vehicle, insurance and one tank of gas for this review.

Specifications as tested:

0-30: 1.8 Seconds

0-60: 3.75 Seconds

1/4 Mile: 11.89 Seconds @ 123 MPH

Average fuel economy: 16.1 MPG over 825 miles