AMG readying four-door GT coupe to rival Panamera

Mercedes-AMG will mark its 50th anniversary next year by launching a large four-door version of its AMG GT coupe.

Codenamed internally the X290, according to Autocar, the new model will be called the GT 4 when it’s unveiled next year.

On sale by 2019, the big Porsche Panamera-rival will share the same 4.0-litre twin-turbocharged V8 as the coupe and recently revealed E63. That means it will produce at least 450kW/850Nm - but it will be even quicker than the new E63 thanks to its lightweight construction.

Expect the GT 4 to hit 100km/h in less than 3.2sec and have a top speed of at least 330km/h.

Instead of basing the GT 4 on the coupe's bespoke aluminium space-frame chassis, according to the Brit mag, the large four-door coupe sits on the same Modular Rear Architecture (MRA) as the E-Class, but will have a “unique" wheelbase and front and rear track, hinting at considerable engineering changes over the standard sedan.

An insider, claimed to be working close the German car-maker's high performance division, also told Autocar that the GT 4 will make use of lightweight materials, like aluminium to lower the AMG sedan's kerb weight to give it a significant performance advantage over the new E63 AMG.

Like the new E63, all-wheel drive will be offered, as well as a less powerful 420kW/720Nm version of the same turbo V8 -- but both versions could outgun any existing AMG models if engineers get their way.

According to the AMG mole, the company is working hard to incorporate a new integrated starter motor (ISG) into the powertrain.

As well as firing up the V8, the ISG uses recovered energy to give the driver short bursts of an extra 15kW for fast overtakes.

Tucked away within the nine-speed AMG Speedshift transmission, the ISG system is powered by a 48V electrical system that might also power active anti-roll bars that reduce roll. News Mercedes will launch this technology surfaced this week along with news of new four, six and eight-cylinder modular engines.

The arrival of the GT 4 will mark the third dedicated series production car engineered by the performance brand and will be followed shortly after by the firm's first ever hypercar, that was announced at the Paris motor show.

Originally, Autocar says Mercedes-AMG was planning a four-door sedan based on SLS supercar but, it’s thought, gave up on the idea over fears such a car would prove too costly.

The new GT 4 is predicted to cost around £120,000 (A$193,000) in the UK when it goes on sale. Sadly, when it reaches Australia expect it to be priced far closer to the $376,900 (plus ORCs) charges for the 2017 Porsche Panamera Turbo.