Benz rules out AMG 63 S E-Class Cabrio

MERCEDES-BENZ has revealed that the all-new E-Class Cabriolet has not yet been engineered for a V8, putting paid to rumours of a 300km/h open-topped rival to the BMW M6.

However, it has been all but confirmed that the company’s most powerful six-cylinder engine – the hotly anticipated M256-series 370kW 3.0-litre bi-turbo in-line unit destined for next year’s closely related new-generation CLS AMG 53 (see related story) – will make the cut as the Cabrio, as well as the Coupe, flagship in the second half of 2018.

Speaking to Australian journalists at the launch of the E-Class Cabrio in Switzerland this week, a senior source at Daimler sounded the death knell for the ragtop V8, saying that there are not enough customers to justify the trouble and expense in developing such as vehicle.

“For the E-Class cabrio, we will only bring a six-cylinder AMG version,” the source said. “There will be no eight-cylinder, no 63 version.”

While the no-show E63 Cabrio might be bad news for hardcore soft-top performance fans, the AMG E53 Cabrio’s 370kW of combined power and a rumoured 550Nm-plus of torque courtesy of a 50kW electric motor should ensure a sub-5.0 second 0-100km/h-sprint time.

Engineered especially for electrification, it features an electric turbocharger and an integrated starter alternator to help reduce off-the-line lag as well as pump up the mid-range torque curve for stronger overtaking.

Not much more is known about the M256-series powertrain in any of the E53 models, including whether the transmission on offer will be the conventional 9G-tronic nine-speed torque-converter auto from the rest of the E-Classes or the AMG Speedshift MCT nine-speed multi-clutch transmission.

With the 245kW/480Nn E400 4Matic variant already featuring all-wheel drive, it is likely that the E53’s outputs will be channelled to both axles too.

The most powerful version of the outgoing E-Class Cabrio was the E500, employing a 300kW/600Nm 4.7-litre twin-turbo V8 to help the convertible hit 100km/h in 5.2s. Discontinued in 2013, its direct successor, the 245kW/480Nm 3.0-litre twin-turbo V6 E400, was only 0.1s slower to 100.

This is in contrast to the outgoing BMW M6, which has a 441kW/700Nm 4.4-litre twin-turbo V8 that is capable of streaking past 100km/h in four seconds flat.

Whether Mercedes-AMG will eventually decide to develop a rival for its Bavarian nemesis remains a secret.