2013 Mercedes-Benz SL65 AMG vs. 2013 Mercedes-Benz SLS AMG GT Roadster

The 2013 Mercedes-Benz SLS AMG GT Roadster is the new hotness in the Mercedes stable. And for good reason. It's visually stunning, the 6.2-liter V8 sounds outstanding, it handles superbly and with a $206,000 starting price requires a serious pocketbook.

But with only 583 horsepower from its naturally aspirated V8, it's not the most powerful roadster in the Benz fleet. Nor is it the most expensive.

Topping out the convertible lineup is the mighty 2013 Mercedes-Benz SL65 AMG. The engine is a 6.0-liter V12, twin-turbocharged and boosted to 21.75 psi. Total output is a whopping 621 hp at only 4,800 rpm. Torque peaks at 738 pound-feet from 2,300-4,300 rpm. Starting price for this much power is $214,445.

For 2013, the SL isn't the old dog it had been. It's got a lightweight, high-stiffness aluminum chassis and is impressive in base SL550 form and upgraded SL63 AMG trim. The bonkers SL65 AMG has these chassis improvements and finally gets the lightning-quick seven-speed AMG Speedshift transmission.

Both hold spots on our list of the 100 Most Powerful Cars of All Time. So which one takes it? The plucky newcomer with its throwback proportions and throaty V8? Or the big dog with more torque than a Freightliner? We went to the track to find out. Let us know which you'd pick in the comments.

Vehicle: 2013 Mercedes-Benz SL65 AMG

Odometer: 1,409
Date: 3/12/2013
Driver: Chris Walton
Price: $221,815 (as tested), $214,445 base (including destination and gas-guzzler tax)

Specifications:
Drive Type: Front-engine, rear-wheel drive
Transmission Type: Seven-speed auto-clutch manual
Engine Type: Twin-turbocharged V12, single overhead camshaft per cylinder bank
Displacement (cc/cu-in): 5,980/365
Redline (rpm): 6,100
Horsepower (hp @ rpm): 621 @ 4,800
Torque (lb-ft @ rpm): 738 @ 4,800
Brake Type (front): 15.4-inch ventilated discs with six-piston fixed calipers
Brake Type (rear): 14.2-inch ventilated discs with four-piston sliding calipers
Suspension Type (front): Independent multilink, gas shocks, coil springs with driver-adjustable hydraulic cylinders
Suspension Type (rear): Independent multilink, gas shocks, coil springs with driver-adjustable hydraulic cylinders
Tire Size (front): 255/35ZR19 (96Y)
Tire Size (rear): 285/30ZR20 (99Y)
Tire Brand: Continental
Tire Model: ContiSport Contact
Tire Type: Asymmetrical summer performance
As Tested Curb Weight (lb): 4,202

Test Results:

Acceleration
0-30 (sec): 1.8 (2.0 w/ TC on)
0-45 (sec): 2.8 (2.9 w/ TC on)
0-60 (sec): 3.9 (4.0 w/ TC on)
0-60 with 1-ft Rollout (sec): 3.6 (3.7 w/ TC on)
0-75 (sec): 5.6 (5.4 w/ TC on)
1/4-Mile (sec @ mph): 11.9 @ 121.1 (11.9 @ 122.1 w/ TC on)

Braking
30-0 (ft): 28
60-0 (ft): 108

Handling
Slalom (mph): 70.3 (66.7 w/ TC on)
Skid Pad Lateral Acceleration (g): 0.95 (0.93 w/ TC off)

Db @ Idle: 42.8
Db @ Full Throttle: 80.3
Db @ 70-mph Cruise: 62.1
RPM @ 70: 1,700

Comments:

Acceleration: If ever there was a car that relied on traction control to keep itself attached to the pavement, the SL65 is it. There's so much instantaneous torque that it feels like an electric car. Turning off traction control and selecting manual shifting (to avoid the wheelspin-induced short-shift to 2nd gear), it took me five attempts to "beat" the electronic governess, and only by a teeny bit. Our advice: Leave traction control on. That's as fast as the car can go.

Braking: Very little dive, no wander or wiggle, and no noise from the ABS system. It required six stops to optimize brakes for the shortest stop. There's plenty of power and heat dissipation built into these brakes.

Handling:

Skid pad: In Sport handling mode, the mighty SL feels like a much lighter car than the 4,200-pound hardtop convertible that it is. Not a creak from the top or windows, so this is a very rigid platform, but the steering seems a little unnecessarily heavy here.

Slalom: Pretty amazing overall performance here considering the mass and relatively little amount of rubber on the ground. I was struck by how quick the throttle response was with so much going on under the hood. We're talking 12 cylinders, two turbos and the ever-vigilant traction control system. Again, the car feels tight and tidy, with crisp steering response, excellent transition from side to side to side and an uncommon ability to put the power down between the last two cones. Even at 70 mph, the surge of instantaneous power is awe-inspiring. An impressive vehicle.

Vehicle: 2013 Mercedes-Benz SLS AMG GT Roadster
Odometer: 4,130
Date: 2/12/2013
Driver: Chris Walton
Price: $233,855 (as tested) $206,000 (base)

Specifications:
Drive Type: Front-engine, rear-wheel drive
Transmission Type: Seven-speed auto-clutch manual
Engine Type: Naturally aspirated V8
Displacement (cc/cu-in): 6,208/379
Redline (rpm): 7,500
Horsepower (hp @ rpm): 583 @ 6,800
Torque (lb-ft @ rpm): 479 @ 4,750
Brake Type (front): 15.4-inch ventilated discs with six-piston fixed calipers
Brake Type (rear): 14.2-inch ventilated discs with four-piston sliding calipers
Suspension Type (front): Double wishbone, driver-adjustable coil-over shock, stabilizer bar (Related: 2011 SLS AMG Coupe Suspension Walkaround)
Suspension Type (rear): Double wishbone, driver-adjustable coil-over shock, stabilizer bar
Tire Size (front): 265/35ZR19 (98Y)
Tire Size (rear): 295/30ZR20 (101Y)
Tire Brand: Michelin
Tire Model: Pilot Super Sport
Tire Type: Asymmetrical summer performance
As Tested Curb Weight (lb): 3,883

Test Results:

Acceleration
0-30 (sec): 1.9 (2.3 w/ TC on)
0-45 (sec): 2.9 (3.4 w/ TC on)
0-60 (sec): 4.0 (4.5 w/ TC on)
0-60 with 1-ft Rollout (sec): 3.6 (4.2 w/ TC on)
0-75 (sec): 5.3 (5.9 w/ TC on)
1/4-Mile (sec @ mph): 11.8 @ 121.5 (12.2 @ 122.1 w/ TC on)

Braking
30-0 (ft): 28
60-0 (ft): 113

Handling
Slalom (mph): 68.8 (67.3 w/ TC on)
Skid Pad Lateral Acceleration (g): 0.99 (0.97 w/ TC on)
Db @ Idle: 54.8
Db @ Full Throttle: 87.5
Db @ 70-mph Cruise: 69.3
RPM @ 70: 2,300

Comments:

Acceleration: Same routine as the last SLS we tested: from RS (Race Start), to S+ (Sport Plus) traction control on, then finally, S+ traction control off. RS was far too generous with wheelspin and was the slowest of the three modes. Best run was all-off in S+ mode with judicious "threshold-acceleration." I think part of the reason RS was so much slower this time (+0.4 second) had to do with the Michelin Pilot Super Sport rear tire pressures set to spec at 42 psi, where the previous SLS wore ContiSport Contact SP tires set to 35 psi. Still, I can't vouch for the supposed 20-hp increase in the SLS GT, as the trap speeds were essentially the same as well, and that's where horsepower always shows up.

Braking: With only firm and hard from which to choose, I chose firm and witnessed distances fall from the first to seventh (and shortest) stop, indicating the tires weren't up to temp when we started. The car has a firm pedal and absolutely zero fade. Predictably shallow jump-in and millimeter-precise modulation, but not the same pedal-pressure progression as our SLS with its carbon-ceramic rotors. Even so, we expected shorter stops.

Handling:

Skid pad: I didn't detect ESC Sport dragging a brake this time. It felt much freer than in our SLS, but full ESC on would take throttle away as the car began to slide at all. Still, it provides very high grip before anything feels like it's being limited.

Slalom: As with our SLS before, this SLS GT cannot be trusted until its tires are up to temp. On-throttle or off-throttle, it wants to oversteer, so you need to be "ahead" of this car at all times. There simply isn't enough time to witness/react. Good thing steering response is super sharp. And given that the softest suspension mode available is as firm as anybody could live with, there is virtually no lean, and it only reacted mildly to the dip at cone #3. Once my confidence with the car increased, I could feel the ESC Sport mode allow the rear of the car to slide controllably past each cone and steal the throttle away at the exit. Other than that, ESC Sport is pretty permissive.

	2013 Mercedes SLS AMG GT	2013 Mercedes SL65 AMG
Curb weight as tested:	3,883	4,202
0-30 (sec.):	1.9	1.8
0-45 (sec.):	2.9	2.8
0-60 (sec.):	4.0	3.9
0-60 with 1-ft Rollout (sec.):	3.6	3.6
0-75 (sec.):	5.3	5.6
1/4-mile (sec @ mph):	11.8 @ 121.5	11.9 @ 121.2
30-0 (ft):	28	28
60-0 (ft):	113	108
Skid Pad Lateral Accel (g):	0.99	0.95
Slalom:	68.8	70.3