The new AMG SL’s mechanicals in detail
The new SL is based on its own unique spaceframe structure. Different in design to that used by the GT to accommodate the lengthened wheelbase and fashioned from a combination of aluminium, carbonfibre, magnesium and steel, it is manufactured at Mercedes’ plant in Bremen, northern Germany, where the roadster is assembled beside the Mercedes-Benz C-Class Estate, EQC, GLC and more.
The whole structure is claimed to weigh just 270kg. However, the increase in dimensions, the packaging of the rear seats and other developments such as the inclusion of a four-wheel drive system for the first time, all contribute to a 125kg increase in weight for the initial top-of-the-line SL 63 variant, which tips the scales at 1895kg. The upshot, however, is a claimed 50% increase in rigidity over the already sturdy structure used by the GT.
Underpinning it all is a largely bespoke steel suspension. It uses a new five-link double-wishbone set-up at the front and a multi-link arrangement similar to that of the GT at the rear, in combination with standard adaptive dampers and new lightweight coil springs developed specifically for this application.
SL 63 buyers also get hydraulically operated anti-roll bars as part of a newly developed Active Ride Control package. These are a first for AMG, replacing the conventional mechanical bars of the lesser SL 55.
Interestingly, Hermann says the switch from the old MRA platform to the new MSA one has allowed Mercedes to position the SL’s axles lower. He claims this brings about a significant lowering in the centre of gravity compared with the old SL.
While a lot is new, the two twin-turbocharged 4.0-litre V8 engines available from the start of UK sales are familiar enough. The M176 unit found in the SL 55 delivers 469bhp and 516lb ft of torque, propelling it from 0-62mph in a claimed 3.9sec and on to a top speed of 183mph. The SL 63 uses the more heavily tuned M177 unit, with 577bhp and 590lb ft, allowing it to dispatch 62mph from standstill in a slightly sharper 3.6sec and reach an impressive 195mph.
As well as an altered intake system, repositioned intercoolers, a new oil pan, changes to its crankcase for added cooling efficiency and a modified exhaust, the latter version of the AMG powerplant benefits from revised active engine mounts. These stiffen and soften according to load, isolating vibrations within the body structure and substantially reducing load change.