Roadsters in Detroit

SLK 320

SLR Roadster

Starting the new year right, Mercedes-Benz brought three new and exciting roadsters to the Detroit auto show: the SLK320, the Vision SLA, and the Vision SLR

Vision SLA

The Vision sports car concept-previously demonstrated by the high-end SLR and Roadster-is growing into a family. Looking far more attractive than the rendering in our January/ February issue, the newest offspring, the Vision SLA concept car, was unveiled at the North American International Auto Show in January.

Based on the A-Class, this simple, light, basic sports roadster is aimed at enthusiasts willing to deny luxury in exchange for an open car that is fun to drive, responsive, light, small, and simple enough to cost-at an estimated $25,000--far less than the SLK. That sounds like a recipe for success.

Although its styling could be simplified, the Vision SLA avoids the current retro fad. Like its bigger brethren the Vision SLR Coupe and Roadster, the SLA's front end takes a cue from the McLaren-Mercedes Grand Prix car. A horizontal "wing" carries twin 50-mm xenon headlights and parking lights, its tips projecting visually through the fenders as LED turn signals.

Following a "transparent technology" theme, engine hood grilles offer a look at the engine and an outlet for air flow. Tall front suspension struts poke honestly through the grilles. Still, the fender-long mirror cowlings appear heavy, and the outboard front turn signals reminded some observers of gills.

The rear of the SLA looks better. Tightly rounded hindquarters (ahem) bear unique taillight/luggage rack mounts, wherein prisms distribute redness from 30 LEDs per side. Brake lights are in the molded rear bumper and in the luggage rack's horizontal strut. Huge wheels with 35-series tires look muscular and purposeful yet aren't over-styled like those on the bigger Visions.

In the cockpit, handsome natural dark brown saddle leather-with exposed edges and finely sewed seams-blends well with primed metal panels, aluminum trim, and carbon-fiber seat shells. Almost everywhere you touch-except the mat aluminum control knobs-you touch leather, including the floor mats. The console-mounted chronometer can be fitted with a leather wristband for use as a wristwatch. The top was not revealed, but you can be sure it's manually operated.

Front-drive Vision SLA concept roadster is compact, saving weight and improving handling. Interior eschews luxury in favor of lightness.

Vision SLR Roadster is closer to production, will be built in partnership with McLaren.

The engine hood tips forward to reveal the 1,898-cc inline four from the A190 city car, which also contributes its five-speed manual transmission plus its front and rear coil spring suspension. The SLA's doors and chassis load-bearing structures are aluminum, even the central floor. The unique A-Class sandwich chassis, with drivetrain under the floor, is not used here;

to keep this sports car low, the engine and transmission live in a more normal front location. Still, in an accident they are designed to avoid the passenger compartment by sliding beneath it. Other safety features involve breakaway bolts in the structure, the normal component of airbags, and fixed roll bars.

Clad here in "Cool Silver" paint, plastic bodywork keeps weight to 2,090 lb, allowing 125 hp to move the SLA to 60 mph in 7.8 sec, a full second quicker than the bigger A190. Top speed is said to be 130 mph, while overall fuel consumption (to European standards) is reported as 33 mpg. The Cd drag coefficient is 0.36.

The front-drive SLA's power steering is electrically driven. Vented disc brakes are clearly visible behind simply sculpted 7.5-in-wide wheels carrying 225/35ZR19 tires. Given an overall length of just 12 ft, 4 in, the SLA is eight inches shorter than an SLK. Given its 92.5-inch wheelbase and 59-inch track, handling should be sprightly (pun intended). Anticipated electronic features are ABS, ESP, Brake Assist, power windows, and central locking, though the last two seem unnecessary.

SLK320

Almost hidden on the second level of the Mercedes-Benz stand, where few noticed it, was the new V-6 powered SLK320, set to reach U.S. showrooms this spring as a 2001 model.

Exterior differences are subtle. The front and rear bumpers and door sills are slightly re-contoured, and body-color paint on the grille, bumper moldings, and door handles gives the car a cleaner look, with new taillights and tailpipe trim as follow-up. The outside mirrors now carry turn signals, too.

Inside, the SLK320 takes a step toward luxury. Gone is the sporty carbon-fiber trim, replaced by your choice of textured aluminum or two woods: a fine-grained brown eucalyptus ("Calyptus Liera") or black bird's-eye maple. The gear lever and steering wheel have wood and leather inlays, while the slightly reworked instrument panel has new FSS indicators. Five interior colors include anthracite, merlin blue, siam beige, magma red, and lotus yellow, at least for European cars. Slightly re-shaped seats get a power option.

Most improvements lie beneath the skin. The V-6 engine is the same trusty unit as in the E and M-Class and the CLK. Here it makes 218 hp and 233 lb-ft from 3,000 rpm, enough for a top speed of 152 mph and 0-60 mph in under 7.0 seconds, compared with 7.2 sec for the 2000 SLK230. A new six-speed manual transmission is standard equipment (the current five-speed autobox is an option), offering short-throw, low-effort shifting, according to DCAG. All 2001 SLKs come with the six-speed as standard gear (excuse the pun). Sixth is not just an econo-cruise ratio; top speed comes in top gear. A bigger, 60-liter fuel tank (up from 53) boosts cruising range.

The SLK320 has standard air-conditioning plus a new rear sway bar and re-tuned shocks. Reduced coil spring height lowers the body five mm, and the ellipsoid firewall structure and side members are strengthened. For the first time, xenon headlights are available, and the new trunk handle has an integrated lock. Look for a drive report in our next issue.

SLK 320 has body-color exterior trim, new paint colors, new wood interior trim option; U.S. prices will be announced in April.
V-6 fits well, boosts torque by 10 percent. New 16-inch wheels are standard.

Other SLKs

The SLK230 Kompressor is also improved. Horsepower is up three to 197, trimming 0-60 time to about 7 seconds and raising top speed to 149 mph. A modified cylinder head with "flow-optimized" intake and exhaust ports is aided and abetted by new ignition coils, a new electronic engine management system, an optimized supercharger, and an exhaust system with air-gap insulated manifold.

Standard fitment on all 2001 SLKs will include ESP, cruise control, side airbags, and new burnished, six-spoke, 16-in alloy wheels. Optional 17-in wheels come in either a seven-spoke design or an AMG monoblock style. Standard wheels carry 205/55 front tires and 225/50 rears; optional ones have 225/45 front and 245/40 rears. Europeans get a new model, the SLK200 Kompressor.

Overall, the SLK has been a huge success. During its first year more than 55,000 were built, at least 50-percent more than planned. As of late 1999, 160,000 SLKs had been sold, and the model has earned more than 35 international awards.

Vision SLR Roadster

This open version of the Vision SLR made its world debut at the Frankfurt show last September and appeared for the first time in the U.S. at Detroit. Compared to the coupe, the roadster's redesigned body has a higher trunk to accommodate the folding top and for aerodynamic purposes. Again, lightness counts. Its bodywork of fiber-reinforced composites (carbon fiber) and aluminum saves 40 percent of the weight of a steel body.

Thanks to a water-to-air intercooler, the supercharged 5.5-liter V-8 makes 557 hp and 560 lb-ft of torque, both at 4,000 rpm, so the Roadster is expected to reach 60mph in just 4.2 seconds, which would be a record for a Mercedes-Benz production car (even the "street" CLK-GTR takes 3.6 seconds.)

The translucent folding top on this concept car is operated manually, and its rear window section can be opened alone. A subtle "diffuser" guides air under the rear of the car to two wings for optimum high-speed stability.

Acting on ceramic brake discs, the electro-hydraulic Sensortronic braking system (new acronym: SBS) sense and calculate brake force required based on cornering, road surface, and other factors. Their sensitivity can be adjusted for comfort.

According to DCAG, both the Vision SLR Coupe and Roadster will be available "around 2003" or "in a few years", so start saving up your quarter-million dollars now.

The Big Show

Finally, a few words in praise of Detroit, which has grown into one of the world's top three auto shows. If you want to see firsthand the products of the fresh thinking going on at Mercedes-Benz-and other companies-this is the show to visit. This year's concept cars and new model unveilings were impressive, with a vehicle for every automotive interest. For car enthusiasts, Detroit in January has become a new tourist destination. FDB