Photos copyright ©2011 Rex Roy / AOL
Inside, the modernized retro theme continues, with our SLK350 tester's circular vent outlets ported through the handsomely contoured dash covered in hand-stitched Nappa leather (like the SLS AMG
). Round analog gauges flank a center digital display in the main binnacle, while a bright, seven-inch LCD handles navigation as well as manipulating the climate control and infotainment systems.
While the interior and exterior are mostly new, from an engineering standpoint, the third generation seems more like a Gen 2.5.5; a facelift of the 2008 facelift. The 2012 SLK rides on the same 95.7-inch wheelbase. It's about an inch longer and an inch wider (overall width and track), and the tidy dimensions help this car stay true to what SLK stands for: Sportlich (sporty), Leicht (light) and Kompakt (compact).
Engines are familiar to fans of the Three-Pointed Star. In the States, we will eventually get two of three available engines for the new SLK: the 1.8-liter turbocharged four-cylinder and the naturally-aspirated 3.5-liter V6. Four-cylinder models will be called the SLK250, while V6 models gets the SLK350 badge. For 2012, both engines gain direct fuel injection in a nod to efficiency. Horsepower, torque and preliminary estimated miles per gallon figures are 201, 229 pound-feet, and 23/31 for the 1.8-liter engine and 302, 273 lb-ft., and 20/29 for the uprated V6. On this trip, only the six-cylinder SLK350 was available for us to drive, as it will be the only model offered when the SLK goes on sale in June. The SLK250 is scheduled for availability in the U.S. later in the model year.
Both engines run their torque through an updated seven-speed automatic modified to accommodate a new fuel-saving start/stop functionality. Unfortunately, cars coming to the USA won't be getting the latter feature – at least for the moment. That's too bad, given where fuel prices are trending and the system's relative smoothness. Mercedes-Benz engineers use the crankshaft position sensor to know which cylinder has stopped closest to the optimum position for re-starting the engine. The engine control module then re-fires that cylinder first, an action that helps smooth out and quicken the re-start event.
To prepare for our drive, we needed to store two large duffle bags and wondered how much room our SLK350's trunk provided. Mercedes-Benz literature claims 6.4 cubic feet with the roof lowered and 10.1 cubes with the roof raised. Since we would soon be driving from sea level through the clouds to the observatory at Teide National Park, some 7,800 feet above the Atlantic in Spain's canary Islands, the top would be down and up depending on the precipitation (or a lack thereof). The trunk easily swallowed two large backpacks and a camera case with the roof stowed. Nifty.
The SLK's hallmark retractable hardtop comes in three varieties: solid steel panels, a tinted roof section or with Benz's trick new Magic Sky Control electrochromatic roof section. The later roof's trick is that the transparent panel can shift its tint from almost clear to heavily darkened.
The glass section is a glass-matrix polymer-glass sandwich in which nearly microscopic rectangular particles are suspended in carrier-type fluid. When a small electrical charge is put through the polymer layer, the particles obediently arrange themselves in a vertical orientation, letting light pass through mostly unencumbered. When the juice is cut via a switch on the windshield header, the particles rotate 45-degrees, blocking most of the light (and heat) attempting to pass through. The shift requires nary a second. (Geek Note: Magic Sky Control uses a similar principle to Delphi's Magnetic Ride Control dampers that control the flow path of damper fluid.)
When it came time to press the starter button and head for the observatory, temperatures were mild, and low clouds hung over our oceanfront starting point. With rain threatening, it neither felt nor looked like top-down driving weather, so the top stayed in place.
The imperfect roads on Tenerife presented a less-than-ideal surface that worked to shake and rattle the SLK. It accomplished neither. The roadster easily absorbed the punishment with the aplomb of a true fixed-roof coupe. Interior noise levels (engine, road and wind) were well subdued, and the exhaust note of the V6 sounded sportier than the same mill in the C-Class sedan. No surprise there, but still a welcome discovery.
Short-wheelbase cars can feel skittish, but the SLK simply doesn't. Even at full throttle with every foot-pound of torque twisting the rear half shafts, the SLK350 felt unshakable and secure.
As we left the island's primary roads for the twisties ascending the extinct volcano's walls to the observatory, the SLK's locked-down feeling continued. Our route took us into the clouds that were heavy with moisture and the narrow roads turned slick. It seemed that the entire ride up the mountain was a Falling Rock Zone, and plenty of rocks littered the asphalt – like we needed more excitement.
Even running uphill, the 302-hp six-cylinder had plenty of power in reserve. Thinking that leaving the electronic stability control in the 'On' position was a good idea, we'd often feel it working to keep the SLK in line. As expected, it immediately curbed any oversteer, but did so in a way that wasn't retaliatory – it simply chided for being overexuberant.
What was unexpected was the so-called torque-vectoring function of the Electronic Stability Control. When diving into a corner under braking, we're trained to expect a certain amount understeer – particular from Mercedes. The SLK senses the understeer and helps to mitigate it by adding a measured amount of braking to the inside rear wheel, helping to increase the car's yaw rate and make it rotate more easily.
We'll have to wait for the AMG-tuned version of the SLK to arrive before this chassis can be completely exploited, but indications are good thus far. Unfortunately, the ESC on the SLK350 cannot be completely disabled. When the dash switch is toggled off, the tires will spin to aid acceleration on snow or through mud, but any yaw immediately triggers a throttle intervention. When the AMG version arrives, expect an option to completely shut down the ESC.
Even with ESC on, the SLK remained a remarkably fun steer. The traditional hydraulic rack-and-pinion box had a natural on-center feel. Rolling off of center, starting at about 5 degrees, the box cranks the wheels with a constant ratio. At 100 degrees of steering angle – just beyond a quarter turn and just before your arms get crossed up – the ratio increases and the wheels turn more quickly. This is a huge help on roads that twist enough that you spend as much time looking out the side glass as the windshield. On the roads of Tenerife, we rarely had to shuffle the wheel or get our arms completely crossed-up.
Somewhere north of 6,000 feet we broke through the clouds and the top went down. It was chilly enough for us to turn on the Airscarf, a feature that blows warm air on your neck. We also put up the Airguide windstop. With the heater cranked up, we remained warm in the cabin, and buffeting was kept to a minimum.
After shooting some photos, we headed back down the mountain. This strained the brakes, as evidenced by the soft pedal and burning odor. However, the Continental SportContact5 tires (225/40R18 front and 245/35/R18 rear) – known for their ability to shed speed with authority – never faltered. The average SLK driver probably isn't going to give their drop-top the same workout, so for daily duty, the standard stoppers should do nicely.
In all, the 2012 SLK's driving experience was a good one. It did, however, leave us wondering about a few things. First, we're looking forward to some time behind the wheel of the lighter SLK250. The tonnage is down by more than 100 pounds and weight distribution should be closer to 50/50. The SLK350's smaller-engined sibling could end up being the better of the two offerings – that is, until the V8 AMG model enters the mix. We'll let you know as soon as we get the chance to try them out.