New Mercedes C43 is a 400PS mild‑hybrid

No, it’s not the full-fat AMG variant. It’s an answer to BMW’s M340i and Audi’s S4 – fast cars in their own right, but not the dedicated performance flagships. With the use of the M139 four-cylinder engine, the new C43 does away with the 3.0-litre V6 the last-generation car used. M139 gets an L on the end in the C43, given it’s longitudinally mounted. The last time a hot Mercedes saloon used a four banger mounted thusly? Over 30 years ago, with the Cosworth-fettled 190E 16-valve. The similarities start and end there, but it’s a fun comparison nonetheless.

The new engine also makes use of an electric turbocharger and a 48-volt electric architecture with a starter-generator and mild-hybrid boost. In theory, there should be little to no turbo lag when exercising this powertrain thanks to the in-turbo electric motor and 175,000rpm compressor wheel speeds. While it is over 40PS up on the outgoing V6, torque is down just a tad to 500Nm (369lb ft). That power goes to all four wheels via the excellent nine-speed MCT transmission as seen in a number of Mercedes models already. 

The 4Matic drive system has a special AMG configuration, splitting the power with a 69 per cent bias to the rear. Performance numbers are strong if not class-leading, with 62mph arriving in 4.6 seconds on the way to a 155mph or 165mph top speed, depending on if you have the AMG driver’s package. Suspension and steering are also AMG-tuned – the C43’s 1,765-1,810kg heft is suspended with active AMG dampers as standard – while the rear end gets a mild steering element too. Bigger brakes clamp 370/320mm steel front and rear discs.

To look at, the C43 brings a subtle bump in attitude for the clean and smooth sixth-generation C-Class. There’s a bit of a chin and a splitter, and the now de rigeuer AMG vertical grille slats are the most obvious tell at the front. Big 19- and 20-inch AMG wheels are a tell from the side, while at the rear slashes in the bumper, a big diffuser and the distinctive circular quad exhausts are nods to the C43’s performance potential. On the inside, liberal lashings of carbon fibre and red accenting are a solid clue as to the AMG-fettled status of the C43, as are the figure-hugging AMG sports seats and red seatbelts. There’s a sports steering wheel with Dynamic Select buttons – Sport and Sport+ modes included – and premium shift paddles, while the monster tablet infotainment screen carries over from high-spec C-Classes.

Take all of that and broaden it by ten per cent in your mind and you’ll more or less have a feel for how the full fat C63 will look, inside and out. Believe it or not, that four-cylinder motor is making its way to the C63 too, albeit with a monster E Performance hybrid element tacked on, for what we expect to be around a 550PS (405kW) combined punch. 

With puffier looks and extra performance, but not a distinctive and characterful V8 engine to distinguish the next C63, this C43 could turn out to be a bit of an AMG sweet spot. Prices for the C43 are expected to start around £50,000, while the C63 will easily be north of £80,000 when it arrives next year, so it could be a bit of a bargain, too. It’ll be interesting to compare the two when the time comes but for now, the C43 is the most C-Class you can get.