|
| Mercedes-Benz | Porsche | Motorcycles & Miscellanea | How Things Work (DIY) Section |
The SLK32 AMG
Outwardly, the SLK32 appears to be a standard SLK230 or 320. There are a number of subtle clues, but confirmation arrives as soon as the supercharged six comes to life. The first time you stab the loud pedal, 332 pound feet of torque will shove you back into the seat. Just about the time the torque lets up, you'll look down at the speedo and recognize that 349 HP makes the world go by a lot faster.
Some may glance at the spec sheet and think this has to be an exaggeration. After all, the SLK320 has a 3.2 liter six as well. The big difference is the kompressor, or as we say in the US - supercharger. Although AMG starts with the same basic 3.2 liter vee six, that's just the starting point. The hand-built kompressor engine retains the SOHC, three-valve per cylinder design, but in addition to the supercharger, the AMG engine gets a new crankshaft, rods, pistons, cams, valve springs, oil pump, exhaust system, and engine computer.
The supercharger is a unique piece of work. It uses Teflon coated helical rotors to produce 14.5 psi of boost. To improve fuel economy and lower emissions, the supercharger is fitted with a computer controlled electromagnetic coupling device that disengages under low load conditions. It disengages and engages so smoothly that many people can't tell when the engine is generating boost.
The supercharged is aided by a liquid to air intercooler that sits in the vee between the cylinder banks. The liquid intercooler is fed by a front mounted radiator. This all helps lower intake temperatures, resulting in more power. The difference in power is impressive. Torque is increased a little more than 50%, while horsepower is raised over 60% (from 221 pound feet of torque to 332, and 215 hp to 349). The results are zero to sixty in the sub-five second range, versus 6.6 for the SLK320 (manual or automatic).
Speaking of transmissions, all SLK32's use an electronically controlled, driver adaptive, five-speed automatic. Some will chastise AMG for not offering a six-speed manual. A manual is available in the R170 SLK230 and SLK320, but not in the AMG. The five-speed automatic has TouchShift, which allows the driver to manually select gears without having to manage a clutch. These transmissions also have an intelligent automatic mode. The transmission computer uses road speed changes, load, and throttle position in determining when to shift. The transmission computer also recognizes both uphill and downhill grades. The transmission avoids annoying shifts back and forth between gears on long inclines, and delays up shifts on descents. Delaying the up shift allows for engine braking exactly as a driver would with a manual transmission. These transmissions are also equipped with SpeedShift. SpeedShift transmissions shift 35 percent faster than normal, and have much stronger internals than the standard SLK automatic.
Being a Mercedes-Benz, the improvements didn't stop with the drivetrain. The wheels and tires, suspension, and brakes are all upgraded as well. The suspension features AMG springs that are stiffer and shorter, resulting in a 1 inch lower ride height. The more aggressive springs are complemented with AMG-spec dampers and thicker sway bars. The wheels are AMG twin-spoke aluminum alloys. The front wheels are 17x7.5, while the rears are 17x8.5. The tires are Pirelli P Zero Rossos. The front tires are 225/45ZR17. The rears are 245/40ZR17. The brake discs are internally vented and 13 inches in diameter up front, 11.8 inches in diameter in back.
The bodywork has subtle styling changes. The SLK32 has an AMG specific front air dam, side skirts, rear apron, and a rear decklid spoiler. A few well placed badges round out the body. The interior is graced with contoured sport seats, two-tone leather, and an AMG specific instrument cluster.
With prices beginning in the low fifties, these were not cheap cars. But then again, most things this good are rarely found on the bargain rack.
|
|
Technical Data
| Model | SLK32 AMG |
| Vehicle type | Two-seat coupe/roadster with powered-operated retractable hardtop |
| Engine | 90-degree V6, screw-type intercooled supercharger |
| Engine material | aluminum |
| Valvetrain | Chain-driven single overhead camshaft per cylinder bank, two intake valves and one exhaust valve per cylinder |
| Valve arrangement | 3-valve technology with two intake and one exhaust valve per cylinder |
| Displacement (cu. in./cc) | 195 / 3,199 |
| Bore (in./mm) | 3.54 / 89.9 |
| Stroke (in./mm) | 3.31 / 84.0 |
| Compression ratio | 9.0:1 |
| Horsepower @ rpm | 349 @ 6,10 0 |
| Torque (lb-ft.) @ rpm | 332 @ 3,000-4,600 |
| Intake system | Screw-type supercharger with intercooler, electronic throttle control, two-stage resonance intake manifold |
| Engine management | ME 2.8 engine control with phase-shifted twin spark ignition, two coils and spark plugs per cylinder, integrated sequential multi-point fuel injection |
| Max. engine speed (rpm) | 6,000 |
| Transmission | AMG SpeedShift five-speed electronically controlled automatic with driver-adaptive shift logic, Touch Shift manual control, actrive braking downshift, optimum gear function performance modes |
| Gear ratios | |
|
1
2 3 4 5 R |
3.59:1
2.19:1 1.41:1 1.00:1 0.83:1 3.15:1 |
| Final drive | 3.07:1 |
| Stability control | Electronic Stability Programming (ESP) integrating single brake application and throttle intervention for yaw control, plus ignition and throttle intervention for wheelspin control |
| Suspension | Four-wheel independent |
| Front | Double wishbone (upper and lower control arms), coil springs, gas-charged shocks, stabilizer bar |
| Rear | Five-link, coil springs, gas-charged shocks, stabilizer bar, anti-lift and anti-squat geometry |
| Steering | Recirculating ball, hydraulic power assist |
| Overall ratio | 15.53:1 |
| Turns, lock-to-lock | 3.1 |
| Turning circle | 32.9 feet / 10.03 meters |
| Front Wheels | 7.5x17-in., 10-spoke |
| Rear wheels | 8.5x17-in., 10-spoke |
| Front tires | 225/45ZR17 |
| Rear tires | 245/40ZR17 |
| Brakes | Hydraulic power assisted 4-wheel discs with 4-channel ABS anti-lock; Brake Assist System |
| Front disc diameter (in./mm; type) | 13.0 / 332; vented |
| Rear disc diameter (in./mm; type) | 11.8 / 300; vented |
| Front disc thickness (in./mm) | 1.26 / 32 |
| Rear disc thickness (in./mm) | 0.87 / 22 |
| Exterior dimensions (in./mm) | |
| Wheelbase | 94.5 / 2,400 |
| Length | 157.9 / 4,010 |
| Width (without mirrors) | 67.5 / 1,715 |
| Height | 50.4 / 1,279 |
| Front track | 58.6 / 1,488 |
| Rear track | 58.5 / 1,485 |
| Curb weight | 3,220 |
| Aerodynamic drag (Cd) | 0.35 with the top up |
| Interior dimensions (in./mm) | |
| Head room | 37.4 / 950 |
| Leg room | 42.7 / 1,084 |
| Shoulder room | 51.7 / 1,313 |
| Capacities | |
| Cabin volume (cu. ft.) | 43.8 |
| Fuel tank (gallons) | 15.9 |
| Performance | |
| 0-60 (seconds) | 4.8 |
| Top Speed MPH | 155 - electronically limited |
| Fuel economy (city/hwy) | 18/24 |
|
|
|
|
|
© 2005 Marcus Blair Fitzhugh
Home | Mercedes-Benz | Porsche | Motorcycles & Miscellanea | How Things Work (DIY) Section