A new transmission grabs the powertrain spotlight
The same 6.2-liter V-8 that powered the previous E63 is under the 2010 E63 AMG's hood. AMG engineers were able to boost peak horsepower to 518 hp, chiefly by lowering the exhaust backpressure. The engine's surprisingly sharp, aggressive bark and deep rumble have been preserved. Overall, though, the more significant powertrain change is the adaptation of the Speedshift DCT seven-speed automatic transmission from the SL63 AMG, which replaces the old car's seven-speed automatic. The Speedshift box uses a wet clutch in place of a torque converter and provides faster shift times and very sweet, rev-matched downshifts. Surprisingly, despite the absence of the torque converter, the transmission still beats any automated manual - including BMW's M-DCT - and most dual-clutch setups with its smoothness both in take-off from a stop and in its automatic shifts. And yet its shift speed effectively gives away nothing to those supposedly sportier gearboxes.
As you'd expect, the driver can tailor the transmission's behavior via a choice of modes. The mellowest, C (for Controlled Efficiency, says Mercedes) is really too mellow for a car like this. It's the economizer setting, starting off in second gear, upshifting as soon as possible, and even relaxing the throttle response. Controlled Efficiency might be great for squeezing out the best-possible mpg rating on the EPA test cycle (expected to be 13 city/19 highway, though official figures aren't yet available), and it's the chief reason AMG is able to boast of a 12 percent improvement in the E63's fuel economy. But, really, who on earth is going to hypermile their nearly-$100,000 German super-sedan?
The next two modes, Sport and Sport+, are subtly different in their programming but virtually indistinguishable on the road. Happily, both seem to intuitively understand the enthusiast driver, unfailingly anticipating gear choices, downshifting under braking, snapping off upshifts with lightning speed, and beautifully matching revs on every downshift, whether automatic or manual. Speaking of manual, if the driver calls up his own shifts via the steering-wheel-mounted paddles, after a few moments of inactivity, the box will resume giving its own orders. Turn the control knob to Manual, however, and the transmission will defer almost totally to the driver; the gearbox will not upshift even at the 7200-rpm redline nor will it kick down in response to a booted throttle.
A final, fifth, position on the transmission control knob is RS, for Race Start (or should that be valet mode?). It's a bit fussy to deal with, though. With the stability control in Sport, you hold your left foot on the brake, choose Race Start, when prompted quickly tap the upshift paddle once to confirm, then immediately floor the accelerator (if you're not fast enough the whole sequence is cancelled and you have to start over), and let off the brake. The E63 effects a wheelspin-free blast that should have you to 60 mph in 4.1 seconds.
The buttons to select the transmission, ESP, and damping modes are alongside the gear selector, which is a console-mounted lever rather than the wimpy column shift in the standard E-class. Sitting next to them is a fourth button, labeled AMG, which - like a BMW's M button - can program and store a driver's preferred settings for transmission, stability control, and damping.
As you'd expect from a car with 518 hp, the E63 is a always ready to drop a couple of gears, let out a deep bellow, and tear ahead down the highway. The massive V-8 makes this car a star of the quick, two-lane pass. A new option for hauling it back down again is carbon-ceramic brakes, although they won't be available in the U.S. market until next year. Like all carbon-ceramic brakes, these offer fade-free, racetrack-ready performance, at a price (expect to be $8000 to $10,000), but unlike most they're - almost - squeal-free and fairly easy to modulate. ...next page >>