Benz's new AMG-fettled G-Wagens

What is a tenth of a second worth? To an Olympian, it can mean the difference between becoming a legend and not even finishing on the podium. To a racing driver, it can be the difference between starting on pole position or back in the pack. To a cricketer, it can be the difference between being smacked in the head or hooking a bouncer for six.

But Mercedes-Benz’s AMG performance offshoot thinks a tenth of a second to 100km/h is, to a select group of people, worth a full, twin-turbo V8-powered G63 off-roader.

Some people, AMG insist, are so enamoured and fixated with V12 engines that they would never even countenance a V8, no matter how good it might be.

That’s why AMG feels it can charge buyers almost twice the price of the V8-powered G 63 for the V12 version of its face lifted G-Wagen, even though the V12 only pips the smaller-engined SUV to 100km/h by a tenth of a second.

While the G63 AMG twin-turbo V8 is, at €137,504, a logical step up from the more-mainstream G500 V8’s €100,000 price tag in Germany, the V12-powered G65 AMG lists at an outrageous €264,180.

Yet AMG insists the low volumes, high investment costs and extreme exclusivity of the 6.0-litre V12 all justify it costing almost twice as much as AMG’s own V8 G63. And, in all likelihood (and if other AMGs are any guide), the G63 will be the better machine.

It doesn’t really matter whether you go for the 400kW V8 G63 or the 450kW G65, because both of them are Quixotic attempts to turn the square-rigged old SUV into an athlete.

Undoubtedly the least agile home AMG has ever thought of for either of the two engines, the G63 and G65 AMG will turn the hard-core rock hopper into something very fast – at least in a straight line and at least up to 100km/h.

The 5.4-litre V8 will smoke the G-Wagen to 100km/h in 5.4 seconds, while the monster, with the 6.0-litre V12, will get there just 0.1 seconds faster. They’re the slowest AMGs available, though, with the G63 topping out at 210km/h and the G65 hitting its limiter at 230km/h.

That won’t stop most people, though, because the V8 has a crushing 760Nm of torque to help it explode in the mid-range, and it chimes in from just 2000rpm. It’s 27kW and 60Nm stronger than the old G55 AMG, and far cleaner. The V12 is even more outrageous, with AMG limiting it to 1000Nm of torque in an effort to coax the expected lifespan out of its seven-speed automatic gearbox.

In spite of Benz’s recent efforts to reduce its fuel consumption, the V12 in particular shows no general interest in the preservation of natural resources, swallowing 17 litres/100km on the combined fuel economy cycle, whilst emitting almost 400 grams of CO2/km. The G63’s consumption figure of 13.8 litres/100km is, surprisingly, a full litre better than the standard G500 V8’s number.

But V12 lovers will need to be committed to the cause because its price will, in Germany, effectively buy two of the G63 AMGs.

It also scores the AMG seven-speed automatic gearbox that is, effectively, a stronger version of Mercedes-Benz’s in-house seven-speed auto with a faster-shifting, stronger, electronically controlled clutch pack sitting at the back of it instead of a hydraulic torque converter.

Its installation means the AMG G-Wagen twins have an Eco mode to go with the Comfort, Sport, Sport+ and paddle-shift manual modes, though it’s hard to imagine anybody paying the V12’s differential over the V8 and then being even remotely interested in its start-stop technology.

AMG has also fiddled with bearings in the engine, the automatic gearbox and the transfer case to lower cruising noises, while both cars also have new wheels, tyres and brakes.

The G63 squeezes new 375mm brake discs and six-piston calipers inside the 20-inch front wheels and 275/50 tyres, while 330mm discs fit neatly inside the rear wheels.

Outwardly, the already-lumpy G-Wagen gets lumpier, with an AMG-spec twin-slot grille with extended holes below the bumper bar for the cooling requirements of the turbocharged engine and LED daytime running lights.

Both cars benefit from the upgrades to the standard G-Wagen’s interior, taking advantage of the new infotainment, internet and satnav hardware and software to come up with a TFT screen, unique AMG dials and seats and more comfort all around.

That doesn’t mean AMG has completely removed the G-Wagen from its off-road roots, because it retains its three locking differentials and the driver-operated switches for them. It also has a new hill-holder, which holds the brakes to help with hill starts.

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