Mercedes SL-class (R231)


Debut: 2012
Maker: Mercedes-Benz
Predecessor: SL-class (R230)



 Published on 15 May 2012
All rights reserved. 

Few cars can dominate its class quite like Mercedes SL. Since W113 series came out in 1963, the SL has rarely been challenged as the world's best luxury roadster. It might be right that Ferrari and Porsche build much sportier alternatives, but when it comes to completeness – especially what most people expect for open-air motoring – nothing can quite compare with the Mercedes. Its domination is evident from the fact that each of its generation usually last for more than a decade! For example, the outgoing R230 lasted for 11 years, following 12 years of R129 and 18 years of R107. It is one of the most enduring designs in modern ages.

However dominating it was, the outgoing R230 inevitably felt tired in its final years. While a facelift done in 2008 kept it fresh to eyes, its interior wasn't so classy due to the fact that its foundation stone was laid down by ex-CEO Jurgen Schrempp during the cost-cutting era. Its chassis looked a bit outdated and heavy beside the aluminum Jaguar XK. Moreover, the powertrains also need overhaul in order to keep up with the trend of reducing emission. All these factors drove the development of the new generation, R231.


Although the R231 represents a vast progress in technology again, we won't say the same to its styling. Compare the new car with the outgoing one, you will find its nose is less sleek, its large headlamps are a bit odd and the clampshell boot lid looks bulky. The new exterior design has abandoned the avant-garde theme that the SL line used to take. Instead, there is a stronger emphasis on classical theme, such as the prominent front grille and side vents that resemble the classic 300SL. As a result, the new car actually looks more conservative than the last generation R230. No wonder in the first road test event Mercedes brought all its predecessors bar the R230 for photo shooting (see the last picture of this report).

The classical theme is carried over to the interior, but unlike the exterior it is pleasing to eyes. A simple twin-dial instrument and 4 circular vents contribute to style and ease of use. The quality is good, as you can expect on a top-of-the-range Mercedes. Leather, wood and metal mix and match flawlessly. The only flaws are the slightly plasticky gauges and the unintuitive Comand control system. As for comfort, the cabin offers generous space for two – unlike SLS – and very comfy seats. There are also some classy features that you cannot find elsewhere, such as Airscarf seats (which blow warm air to your neck to allow open-air motoring even in winter) and a glass roof with Magic Sky Control (which utilizes electrochromic technology to adjust transparency from clear to complete darkness).


The retractable roof system is outstanding. Wind noise and buffeting are very well suppressed, thanks partly to an electric wind-blocker risen behind the cockpit. An excellent aerodynamic drag – 0.27 with the roof in place or 0.32 with it stowed away – contributes to the refinement, too. In coupe form, the cabin feels as refined as in an S-class. In open form, its structure still feels rock solid. There is no hint of scuttle shake or steering column vibration even on bumpy surfaces.

Such a solidity must thanks to a new aluminum monocoque chassis. Having experimented with SLS, Mercedes finally follows the footsteps of Jaguar (XK) and Audi (R8) to put aluminum chassis into mass production. Some 89 percent of the SL's monocoque is made of aluminum, no matter by means of chilled casting, vacuum casting, extrusion or stamping. The others? Well, the roof frames are made of even lighter magnesium, ditto the rear bulkhead. The nose cone is made of plastic in order to achieve the softness to comply with pedestrian safety regulations. Steel is used only at the tubular windscreen pillars and header to provide the required strength for rollover protection, as aluminum ones would have been too thick for good visibility. Mercedes claims the aluminum chassis is 20 percent stiffer than the old one, yet it saves 110 kg compare with an equivalent steel monocoque. More important to us is the final kerb weight: a new SL500 tips the scale at 1710 kg, undercutting the old car by 125 kg. Even without inspecting the engine bay, we can be sure that the new car is quicker.


As before, the chassis rides on by multi-link suspensions at all corners. The front control arms and steering knuckle are now made of aluminum to cut unsprung weight. The same goes for the whole rear suspensions. Steel springs and electronic adaptive damping is equipped as standard, while Active Body Control (ABC) suspension continues to be optional. Following the industrial trend, the steering has switched to electromechanical assistance. This also enables variable gear ratio and speed sensitive assistance easily. The only major part remains unchanged is the 7G-Tronic automatic transmission. The rumored 9G-Tronic is not going to arrive anytime soon.

Two engines are offered:

SL500 (or SL550 for the US market) is powered by the new twin-turbo, direct-injected 4.7-liter V8 already introduced to S-class. It produces 435 horsepower and 516 lbft of torque. Needless to say, performance is much improved over the old, 388hp / 391 lbft 5.5-liter V8. 0-60 mph acceleration is shortened from 5.3 to merely 4.5 seconds. Meanwhile, EU combined consumption is reduced by 22% to 29.8 mpg, partly thanks to the automatic stop-start and taller 7th gear.

SL350 switches to new direct-injected 3.5-liter V6. Horsepower is actually down by 10 ponies to 306 hp, but torque is up slightly to 273 lbft. It is primarily the lighter body that accounts for the 0-60 mph improvement from 5.9 to 5.6 seconds. Fuel economy takes a 30 percent leap to a remarkable 41.5 mpg.


On the Road, the SL500 performs extremely well for what it is supposed to do: a relaxing cruiser. Its power is creamy smooth. Engine noise is barely audible at cruising speed. Performance is effortless, as there is so much torque available from just above idle. Seamless is the best description to its gearshift and ride quality. Most roadsters ride well on motorways, but no one else excels on a variety of surfaces like this car. You glide over back roads without noticing how poorly they are surfaced. The lack of shakes, vibration and noise enhance this sense of smoothness. In fact, it is so smooth that the driving experience could be a little sleepy. Call this the roadster version of S-class.

Benefited by the more direct steering, wider tracks and stiffer chassis, the new SL turns into corners more responsively. It also grips and brakes better than the old car. Unfortunately, this is still no sports car. Its biggest problem is the variable-ratio electric power steering – unnaturally quick, inconsistently weighted and lacks feel. It fails to tell you the grip level at the front tires, thus you never get the confidence to attack corners at full speed. The active body control suspension also fails to deliver a fluent handling. Drive the SL up to 8/10 effort and it feels remarkably stable. Push it towards the last 20 percent and its fine dynamics distorts heavily. Understeer enters the scene first. The steering becomes imprecise. The ABC gives up near the cornering limit and relays each road bump into the cabin. The car becomes unstable and ESP intervenes to correct things. On the lighter SL350 with standard steel springs and adaptive dampers, the aforementioned problem is less pronounced. It feels more agile to steer, and the handling is more progressive. Having said that, its handling is still not as fluent and engaging as its direct rival Jaguar XK, let alone the much much sportier 991 Cabriolet.


A dream collection

That finding is quite sad considering how much Stuttgart has invested into the car. Individually inspected, the new SL has many merits, e.g. a flawless coupe-cabriolet roof, a spacious and comfortable cabin, impeccable ride and running refinement, high build quality, powerful V8, aluminum chassis, green credential and many high-tech gadgets. However, its overall result is less than the sum of its components. It might still be the best luxurious roadster on earth (if you emphasize on luxury), but for the first time in 23 years the SL no longer feels ahead of its time, just like what its exterior suggested.
Verdict: 
 Published on 18 May 2012 All rights reserved. 
SL63 AMG

We are a little disappointed with the dynamic aspect of SL500, mainly about its steering and on-limit handling. However, that is not the end of the world. Most customers purchasing the SL500 put quality, comfort and refinement on higher priority than driving thrills. That has been the case since the very beginning of the line. A small portion of customers who demand more driving excitement is to be dealt with AMG. As before, the new SL offers two AMG models, SL63 and SL65. Also like before, we would choose the SL63 instead of the flagship model because its lighter engine results in a more balanced package, hence better handling.

Enhanced with more aggressive grilles, bumpers, intakes, aero kits, thin-spoke wheels and quad-rectangular exhaust, the AMG model is definitely better looking than the standard car. It corrects some of the bulkiness and contradiction of that car, resulting in a more desirable form. While Maserati Gran Turismo / GranCabrio is still our favourite design, the AMG's unique character is not to be ignored. Inside, the revision from the regular SL is subtle, but the dark color scheme and carbon-fiber trims are very effective to enhance the sense of occasion.


The center of modifications is the engine, of course. Following S63, CL63 and E63, this is the fourth AMG model to employ the new 5.5-liter twin-turbo V8 dubbed M157. Thanks to forced induction, it doesn't need to rev as hard as the old 6.2-liter M156 yet it can easily achieve more torque, especially at lower rev. 590 pound-foot is available from 2000 to 4500 rpm, compare with the old engine's 465 lbft at 5200 rpm. As for top-end power, it also trumps the old one with 537 hp / 5500 rpm versus 525 hp / 6800 rpm. Moreover, with the help of direct injection, automatic engine stop-start and revised gearing, fuel consumption drops by 30 percent, at least according to its official EU combined rating. Apart from cool figures, the new engine also excels in subjective feel.
AMG did an excellent job to give it a quick throttle response and an exhaust note nearly as marvelous as that of the 6.2.

And then there is the Performance pack. Its remapped ECU lifts the maximum boost pressure from 1.0 to 1.3 bar, taking the output to 564 hp and 664 lbft. It goes without saying that this is the easiest way to earn extra profit. Increased power aside, the Performance pack comes with a limited slip differential, and its speed regulation is lifted from the usual 155 mph to 186 mph to please those fascinated to see "300 km/h" on the speedometer. That said, the SL63 can easily exceed 200 mph if it is fully derestricted.


As before, the AMG model uses a 7-speed MCT gearbox with AMG Speedshift program. While it is derived from the regular 7G-Tronic, it has the torque converter replaced with a wet multi-plate clutch to enable quicker gearshift and even a launch mode. The company claims 0-60 mph take 4.1 seconds, or three-tenths quicker than the old car. I won't be surprised if some American magazines manage in the high 3-seconds range.

Concerning chassis, the aluminum construction of R231 enables the SL63 to have its kerb weight cut by 125 kg. That should benefit performance as well as agility. Meanwhile, the wider tracks – up 50 mm and 52 mm front and rear respectively – enhance roadholding and cornering stability. Compare with the regular SL, the AMG version has its ABC suspension tuned firmer. The AMG wheels house monster-size brakes, no matter with steel or ceramic discs. It also fitted a different steering rack – a constant-ratio electromechanical steering instead of the variable-ratio unit on lesser models. Obviously, AMG dislikes the steering on the standard car like us. To certain extent, the change is an improvement. Its response to steering angle is more linear, and the level of assistance is more consistent. Nevertheless, it is still far from perfect. Its initial response is still too aggressive to feel intuitive, and it is still devoid of road feel. The steering remains to be the Achilles' heel of the car.


Still, its handling is much improved over SL500. Grip, body control and braking are all superior, allowing the car to attack corners at higher speed yet with more confidence. Understeer is better contained. Should you turn off the ESP and floor down the throttle, the tremendous torque will easily spin the rear wheels and turn the car sideway, revealing the hot-rod side of AMG. Such personality contrasts to the clinical approach of Ferrari California or Porsche 991. Those cars are apparently lighter and more agile. On the big AMG, you can feel more of its mass. It uses electronic suspensions, quick steering, wide tires and big brakes to mask it mass reasonably well, but in the process you lose some sensitivity and transparency that only lighter, better balanced machines can provide. This mean while the SL63 is highly capable in straight line and in fast bends, it is not as enjoyable to attack mountain roads as some rivals.

However, bear in mind that the SL63 is a high-speed luxury GT, it is hard to fault. The power and sound produced by its twin-turbo V8 is just amazing. The MCT transmission is a good compromise between response and refinement. The ride is firmer than that of lesser SLs, but still very comfortable if you leave the ABC in the softest setting. The interior, the roof and wind management are first rate. While Jaguar XKR-S, Maserati MC Stradale and Ferrari California are more fun to drive, none of them are as well rounded as the big Mercedes.

Verdict:
 Published on 13 Apr 2013
All rights reserved. 
SL65 AMG


When SL65 AMG debuted in 2004, it received a cordial welcome by car lovers and journalists. Its 6.0-liter twin-turbo V12 offered 136 more horsepower and 222 pound-foot more torque than the supercharged SL55 AMG, enabling a performance nearly matching the mighty SLR McLaren yet costing just a third of its price. It made sense to the millionaires who pursued supercar performance and GT refinement simultaneously.

Fast forward to 2013, the new generation SL65 AMG is powered by much the same V12, albeit with modified turbos, manifolds and exhaust to liberate another 18 hp to a total of 630 hp. The headline torque of 1000 Nm or 738 lbft remains unchanged. Its 0-100 mph sprint is improved from the previous 12.9 to 11.8 seconds. This is not just down to the increased power but also two other factors: 1) kerb weight is down by 160 kg thanks to the new aluminum chassis; 2) the outgoing 5-speed automatic transmission is finally replaced with a high-torque version of 7G-Tronic. Sadly, top speed remains electronically limited to 155 mph. While the lesser SL63 may opt for a performance pack to raise the limit to 186 mph, the flagship model is not as lucky.




The SL65 still impresses with its strong straight line performance. Its power delivery is seamless and instantaneous as the biturbo V12 has a flat torque curve and very little turbo lag, while the new gearbox shifts smoothly. However, it no longer presents a significant performance edge over the new SL63. It offers only 66 more horsepower and 74 pound-foot more torque, while it carries an extra 105 kilos. The official 0-60 mph sprint is just 0.2 seconds quicker. This makes its thick price premium (£170,000 vs £110,000) hard to justify. Moreover, the V8 engine's thunderous noise sounds far more exciting than the V12's cultured soundtrack. Its MCT gearbox reacts quicker to throttle than the torque-converter auto. Its lighter nose also results in a sharper turn-in than the SL65, which handles more like a GT than sports car. Meanwhile, by GT standards the ride of SL65 is probably too hard, at least on country roads.

If you have £170,000 to spend, you can have plenty of more desirable choices, such as Ferrari 458, McLaren MP4-12C and Mercedes' own SLS AMG. If you are more concerned of everyday usability, a Ferrari California, Aston Martin Vanquish or Bentley Continental Supersports could be better options. Even if you prefer the traditional philosophy of AMG, you would find no sensible reasons to choose the SL65 over the V8-powered SL63. The flagship SL65 is by no means a bad car, but it is virtually superfluous now.
Verdict:
 Published on 8 Mar 2016
All rights reserved. 
SL facelift 2016


The current generation Mercedes SL, or R231, is technically advanced, luxurious and well built. However, its biggest fault is styling, in particular its nose. I suspect this is the main reason why it gets less popular than its predecessors and is rarely seen on roads. After nearly 4 years, Stuttgart finally gives it a desperately needed facelift. The new nose is certainly more handsome than before. It is more sculpted and refined. The grille is decorated with radial mesh elements in the background like A-class. Like the 2013 E-class facelift, it is the best one can hope to achieve in a facelift, and its designer has to be praised. However, the rest of the package is untouched thus still leaves something to be desired. If you are looking for the most beautiful Mercedes coupe, turn to S-class Coupe or AMG GT.

As usual, the facelift is accompanied with some updated engines. The entry-level SL400 has its 3.0-liter twin-turbo V6 boosted from 333 hp to 367 hp, and its maximum torque is improved by 15 lbft. 0-60 mph acceleration is quickened to a respectable 4.7 seconds, no wonder its American version is badged SL450 instead. Meanwhile, SL500 (SL550) gains another 20 horsepower to 455 hp, finally matching other Mercedes “500” cars. It takes only 4.1 seconds to go from rest to 60 mph, almost a match to the unchanged SL63 and SL65 AMG. Both the SL400 and SL500 have their 7G-Tronic gearbox upgraded to 9G-Tronic, which enhances smoothness and fuel economy further. In manual mode it is still a bit less obedient than the best ZF gearboxes though.

In the chassis, the only change is adding Curve Tilt function to the Active Body Control suspension. Like S-class Coupe, this feature tilts the car for a couple of degrees in fast cornering to counter the g-force acted on the occupants. Like that car again, it feels unnatural, actually reduces feedback thus is best to be avoided. I would have liked Mercedes to add 4-wheel steering to sharpen its handling, but Mercedes is okay with its comfort-biased manner. After all, the SL is a luxury roadster rather than a true sports car.
Verdict:
Specifications





Year
Layout
Chassis
Body
Length / width / height
Wheelbase
Engine
Capacity
Valve gears
Induction
Other engine features
Max power
Max torque
Transmission
Suspension layout

Suspension features
Tires

Kerb weight
Top speed
0-60 mph (sec)
0-100 mph (sec)
SL350
2012
Front-engined, RWD
Aluminum monocoque
Mainly aluminum
4617 / 1877 / 1315 mm
2585 mm
V6, 60-degree
3498 cc
DOHC 24 valves, DVVT
VIM
DI
306 hp / 6500 rpm
273 lbft / 3500-5250 rpm
7-speed automatic
F: 4-link
R: multi-link
Adaptive damping
F: 255/40ZR18
R: 285/35ZR18
1610 kg
155 mph (limited)
5.6 (c)
-
SL500
2012
Front-engined, RWD
Aluminum monocoque
Mainly aluminum
4617 / 1877 / 1315 mm
2585 mm
V8, 90-degree
4663 cc
DOHC 32 valves, DVVT
Twin-turbo
DI
435 hp / 5250 rpm
516 lbft / 1800-3500 rpm
7-speed automatic
F: 4-link
R: multi-link
Active body control
F: 255/35ZR19
R: 285/30ZR19
1710 kg
155 mph (limited)
4.5 (c) / 4.1* / 4.0** / 4.3***
9.6* / 9.7** / 9.9***
SL63 AMG
2012
Front-engined, RWD
Aluminum monocoque
Mainly aluminum
4633 / 1877 / 1300 mm
2585 mm
V8, 90-degree
5461 cc
DOHC 32 valves, DVVT
Twin-turbo
DI
564 hp / 5500 rpm
664 lbft / 2250-4750 rpm
7-speed MCT
F: 4-link
R: multi-link
Active body control
F: 255/35ZR19
R: 285/30ZR20
1770 kg
186 mph (limited)
4.1 (c) / 3.6* / 3.5**
7.9* / 8.0**




Performance tested by: *C&D, **MT, ***Autocar





Year
Layout
Chassis
Body
Length / width / height
Wheelbase
Engine
Capacity
Valve gears
Induction
Other engine features
Max power
Max torque
Transmission
Suspension layout

Suspension features
Tires

Kerb weight
Top speed
0-60 mph (sec)
0-100 mph (sec)
SL65 AMG
2012
Front-engined, RWD
Aluminum monocoque
Mainly aluminum
4633 / 1877 / 1300 mm
2585 mm
V12, 60-degree
5980 cc
SOHC 36 valves
Twin-turbo
Twin-spark
630 hp / 4800 rpm
738 lbft / 2300-4300 rpm
7-speed automatic
F: 4-link
R: multi-link
Active body control
F: 255/35ZR19
R: 285/30ZR20
1875 kg
155 mph (limited)
3.9 (c) / 3.7*
8.1*
SL400
2014
Front-engined, RWD
Aluminum monocoque
Mainly aluminum
4617 / 1877 / 1315 mm
2585 mm
V6, 60-degree
2996 cc
DOHC 24 valves, DVVT
Twin-turbo
DI
333 hp
354 lbft
7-speed automatic
F: 4-link
R: multi-link
Adaptive damping
F: 255/40ZR18
R: 285/35ZR18
1655 kg
155 mph (limited)
5.0 (c) / 4.6*
11.1*




























Performance tested by: *C&D





Year
Layout
Chassis
Body
Length / width / height
Wheelbase
Engine
Capacity
Valve gears
Induction
Other engine features
Max power
Max torque
Transmission
Suspension layout

Suspension features
Tires

Kerb weight
Top speed
0-60 mph (sec)
0-100 mph (sec)
SL400
2016
Front-engined, RWD
Aluminum monocoque
Mainly aluminum
4631 / 1877 / 1315 mm
2585 mm
V6, 60-degree
2996 cc
DOHC 24 valves, DVVT
Twin-turbo
DI
367 hp
369 lbft
9-speed automatic
F: 4-link
R: multi-link
Adaptive damping
F: 255/40ZR18
R: 285/35ZR18
1660 kg
155 mph (limited)
4.7 (c) / 4.5*
11.2*
SL500
2016
Front-engined, RWD
Aluminum monocoque
Mainly aluminum
4631 / 1877 / 1315 mm
2585 mm
V8, 90-degree
4663 cc
DOHC 32 valves, DVVT
Twin-turbo
DI
455 hp
516 lbft
9-speed automatic
F: 4-link
R: multi-link
Active body control
F: 255/35ZR19
R: 285/30ZR19
1720 kg
155 mph (limited)
4.1 (c)
-




























Performance tested by: *C&D





AutoZine Rating

SL-class


SL63 AMG


SL65 AMG



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