Mercedes-AMG GT S is hitting Australian streets this July with its howitzer aimed at rival Porsche 911. Lighter and cheaper than the $467,965 SLS, the $295,000 GT S features a sculptured body, agile chassis and a cracking new engine.
Named M178, the 4.0-litre twin-turbocharged V8 engine is a handmade-by-one-person-only centre piece. Torque is produced low in the rev range (650Nm at 1750-4750rpm and 375 kW at 6250 rpm), the result of a combination of ‘hot inside V’ turbo manifold design and sequential turbochargers reaching 17.4psi of boost within an already high 10.5:1 compression ratio. Typical of low rpm-high torque motors, the bore and stroke is undersquare at 83.0 x 92.0mm, and in juncture with a drysumped design the combination allows the engine to be built smaller and lighter, and with a lower centre of gravity than conventionally required.
Interestingly, the engine specs are similar to that of the 2.0-litre engine AMG deployed in A-Class vehicles.
Technology has been borrowed from Mercedes F1 experience, with Nanoslide liners protecting the high-tolerance specs with twice the resistance of traditional cast iron types.
Acceleration is stellar, with GT S launching from 0-100km/h in 3.8 seconds, and reaching a top speed of 310km/h.
GT S features a front/rear weight distribution of 47/53 per cent, a balance reached in part by placement of the engine front-mid, and the 7-speed DCT transmission mounted transaxle (in the rear). By way of comparison, Porsche’s 911 has a weight distribution ratio of 39/61 per cent and Audi’s R8 43/57 per cent front to rear.
The transaxle transmission places power to rear 295/30/20 tyres via an electronic locking differential, which provides more immediate and sensitive control than a traditional mechanical unit.
Double-wishbone suspension is deployed all-round and constructed from forged aluminium – a method of construction that decreases unsprung mass in components, allowing for finer tuning of suspension geometry and control of camber curve throughout varied cornering conditions.
AMG Ride Control sports suspension is standard, controlled with three variations of dampening – ‘Comfort’, ‘Sport’ and ‘Sport plus’.
Although stopping power should be well taken care of via 390mm composite brakes, optional 402mm front and 360mm rear ceramic discs are available.
Featuring a next generation small-capacity V8, quality chassis engineering and cheaper pricing over the SLS, GT S will provide some serious competition when launched in July. Check back for our first drive soon.
|Specs||2015 Mercedes-AMG GT S|
|Price||$295,000 (plus on-road costs)|
|Engine||3982cc twin-turbocharged V8|
|Power||375kW at 6250rpm|
|Torque||650Nm at 1750-4750rpm|
|Power to weight||4.19kg/kW|
|Wheels||19-inch front, 20-inch rear alloys|
|Tyres||265/35/19 Front, 295/30/20 Rear|