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Vehicle type: front-engine, rear-wheel-drive, 2-passenger, 2-door roadster -
Estimated base price: $48,000-$60,000 -
Engines: 3.5-liter DOHC 24-valve V-6, 268 hp, 258 lb-ft; 5.4-liter SOHC 24-valve V-8, 355 hp, 376 lb-ft -
Transmissions: 6-speed manual, 7-speed automatic with manumatic shifting -
Wheelbase: 95.7 in -
Length/width/height: 160.7/70.4/51.1 in -
Curb weight: 3250-3400 -
Manufacturer's performance ratings: Zero to 62 mph: 4.9-5.6 sec, Top speed (governor limited): 155 mph -
Projected fuel economy: European combined cycle -
(mfr's est): 20-23 mpg Tthe SLK lays on horsepower as well. Mercedes sends the U.S. two flavors from its freezer, a new 268-hp DOHC 24-valve 3.5-liter V-6 for the SLK350, and the mighty 355-hp SOHC 24-valve 5.4-liter V-8 for the SLK55 AMG. The V-8 already does its locomotive impersonation in the CLK55 and G55, among others. The V-6 is new, the first engine of many to come that will shred the current Mercedes rulebook. The company has been in the single-cam, three-valve, twin-spark business for more than a decade, having produced V-6s, V-8s, and V-12s off the same basic engine template. Then, the design was said to be better for emissions and fuel economy, especially when paired with the company's cylinder-deactivation system. Now "the customer wants power, so that is why we changed to four valves," says Kay Dietzel, combustion development director for Mercedes gasoline engines. Both the three-valve head and the cylinder-deactivation system will be ditched for good when the redesigned S-class appears in 2005. |
| The 3.5's starting point was the old 90-degree 3.2-liter V-6 block. The new engine shares its bore centers but not its bore, adding 3.0 millimeters (to 92.9), and 2.0 millimeters to the stroke (to 86.0). The compression ratio also rises, from 10.0:1 to 10.7. A dual-length intake plenum strategizes the breathing, and variable-valve-timing adjusters on all four cams contribute to a table-top torque curve. The 258 pound-feet pull from 2400 rpm through to 5000 rpm. Grams were trimmed off the reciprocating components, millimeters shaved by using helical gears instead of dedicated chains to drive the exhaust cams. | Is Mercedes learning how to build sports-car engines? "It's not that we just learned these things, it's that we did them," says Dietzel. In a drive through the mountains of Majorca, the SLK350 with a six-speed manual (the bigger SL's new seven-speed automatic is also optional on the SLK) spun its rear rubber willingly, the new engine blipping and blatting with a Honda's hair-trigger throttle response and cyclone-smooth spins up to its 6500-rpm redline. There's more sportlich in the chassis, too. The recirculating-ball steering is no longer shared with heavy trucks and Maybachs, the new SLK's wheel turning a quick and friction-free rack-and-pinion. Mercedes skimmed pennies by replacing the old front unequal-length control arms with struts, but some of BMW's strut-tuning genius found its way over to Stuttgart. The SLK now darts from corner to corner with prompt and precise responses, taming its mass with clipped body roll and reliably firm brakes. Sadly, the SLK55 AMG on hand was show only, reserved for a later introduction. Mercedes promised the world a new sports car in 1997. Deliveries are set to begin this year. |
