2017 Mercedes-AMG GLS63 review

Rating: 7.5
$150,500 $178,970 Dealer
  • Fuel Economy
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Is there such a thing as too much power? With the Mercedes-AMG GLS63 and its 430kW twin-turbo V8, James doesn't think so.
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In the USA (where else) there used to be a guy who would show up to county fairs, air shows and drag racing events in what can only be described as a nitro-powered school bus.

This yellow rectangle defied conventional aerodynamics by just muscling the atmosphere out of its way, as it thundered down the quarter mile, usually just on two back wheels, shooting fireworks all the way to a comfortable 12-second pass.

While it may sound like the sideshow plot of a Dukes of Hazard episode, the ‘Cool Bus’ is the perfect cultural simile to the 2017 Mercedes-AMG GLS63.

Sure, it isn’t yellow, but the 580 horsepower, four-wheel drive, seven-seater school-run machine completes the standing 400m in about the same time as that 1000hp, wheelie-popping yellow bus. And while it can’t shoot fireworks, it sounds like it can and that’s just as important.

It is a monstrous consumption device, devouring fuel, tyres, brakes and tarmac as fast as its 2580kg will allow. And at $219,950 (all prices are noted before options and on-road costs) the ride isn’t cheap.

As an actor on a stage, the GLS63 plays all parts in Beauty and the Beast.

The AMG body styling, 22-inch vaned wheels and recent front-and rear lamp and fascia updates are for Belle. The dating but still comfortable, luxurious and well-equipped interior represent the castle, and that 430kW, 760Nm twin-turbocharged 5.5-litre V8 is pure Beast.

The thing is, it’s also as obnoxious as Gaston, and as sensible as the talking teapot.

Updated midway through last year, the GLS range starts at $117,950 for the GLS350d. That’s more than $100,000 less for the same platform vehicle. We’ll even be fair and suggest the $136,950 GLS 350d Sport, which matches the muscular look and lengthy equipment list of the ’63, at an $83,000 saving.

That’s the same seven-seat interior layout, the same mid-generation Mercedes-Benz dashboard, the same powered steering column, the same number of airbags (seven – including full length side-impact curtains), the same light-up side steps, and even the same standard sunroof.

You even score two extra gear ratios in the lesser models, as they have the newer nine-speed 9G-Tronic automatic transmission, where the GLS63 has the seven-speed Speedshift Plus 7G-Tronic. It's almost inconsequential anyway, as I'd wager most GLS Benz es never wander out of the D setting...

The COMAND infotainment system works just as well, all the driver assistance technology and other gizmos operate the same, even the power-folding but manual un-folding seats to get access to the third row are just as heavy and annoying as in the lower grade car.

In fact, if you ignore the extra whomp under the bonnet, the GLS63 scores only a few extra luxuries for its $83k premium. Massage seats, heated and cooled cupholders, soft close doors. You know, the essentials.

If you are genuinely in the market for a GLS, the 350d Sport is the sensible car (you can read our review of it here, or even the moderately less sensible GLS500 here). At urban speeds the diesel 350 basically has everything and does everything the big AMG does. It is the better car.

But let’s face it. I’m here, you’re here, not to chatter about sensible seven-seaters but to talk about power. Lots and lots of power.

And in this regard the GLS63 delivers like FedEx.

Try some maths on for size.

The 430kW V8, an improvement on the much more pedestrian 410kW in the pre-update GL63, has the energy delivering equivalent of 370 million calories, per hour. That’s the same as burning through 750,000 Big Macs every 60 minutes.

Take into account the 2580kg mass of the Mercedes, and you get an energy density of 143 calories per gram of GLS.

Pure fat only contains 9 calories per gram, which means the ‘six-three’ brandishes energy 16 times that of pure fat. If you know your maths, you’ll know that 16 is a fourth power number, often called a tesseract.

So, yep, the GLS is convolutedly related to the cube that powers a whole bunch of Marvel movie plots.

Mic, dropped.

In practical terms though, the experience of nailing the throttle and rocketing to 100km/h in under five seconds is enough to make you wish you hadn’t had one of those Big Macs, let alone three quarters of a million of them.

You can change gears with the steering wheel-mounted paddles if you want something to do, but to be honest, the gearbox is best left to just do its thing. The Speedshift transmission is still a conventional automatic but uses a series of clutches rather than a torque converter to transfer drive.

Shift timing and harshness adapt to the chosen drive mode and it is smooth and swift enough in any setting that you don't need to worry much more about it. No one buying a GLS63 has ever asked how it works, so don't be the first.

From standing start, the wet clutches slip and the big GLS squats slightly on its air suspension, sets off an explosion from the exhaust and the images rushing past the windscreen start to blur, until you come to a corner.

I’ll preface this by saying when you drive the GLS like a regular person doing regular things, it handles quite well for an upper-large SUV. The ride is comfortable, but not supremely plush, and there’s a sense of mass as you motor along, but it’s an easy and relaxed cruiser.

Try to do the same thing when the accelerator is approaching the horizontal, and things change. This isn’t a corner car.

Tip it in to a bend, and the high centre of gravity and husky nature of the Mercedes result in a top-heavy sensation for all occupants. The car features the active curve suspension system, which actually helps mitigate roll through corners, and while it works to a certain extent, the sheer pace of the ’63 all but overcomes it.

It’s not as though the car has reached its handling limit though, the 22-inch wheels and 285mm-wide tyres provide excellent grip, the barrier is more one of passenger comfort. With an enthusiastic driver behind the wheel, the GLS63 has the soft promise of a ferris wheel but the reality of the gravitron.

Much of these stomach tightening g-forces come from the almost instantaneous response from the twin-turbo V8. All 760Nm can be requested from barely an idle at 1750rpm. This is an improvement, however subtle, over the older car’s 2000rpm.

And like all good things, or a truck-load of Big Macs, this is extremely addictive.

Stomp on the pedal, surge forward into hyperspace with a Wookie-like growl, back-off with requisite crackles and pops from the exhaust. Rinse. Repeat. You are the hot-rod school bus.

Ultimate energy equations and powerful shenanigans come at a cost though. The GLS63 has a 100-litre fuel tank, which for a little bit of context would power my father’s Peugeot 308 wagon for close to 2500km. That’s enough to drive from Melbourne to Hamilton Island (Airlie Beach) in the Whitsundays.

Conversely, the GLS63, when driven, ah… by me, can make just 20 per cent of that journey. Driving in convoy with Robert jaunting off to relax in the sun, I’d be stuck in Wagga Wagga.

A minor exaggeration, maybe, as casual cruising will see the fuel sipped at 12.9L/100km, but during our time with the car, a brief stint of throttle usage saw this rise quickly to over 20L/100km, and by the end of the week the big white Benzo was approaching the 30L/100km mark.

Amusingly you can only get a point summary of this. There is no fuel consumption over time graph like in other Mercedes cars. You don’t even get the ECO graph in the central instrument display, or an ECO drive mode.

It is as though during the engineering briefing, someone heard ‘you don’t want to know’ when it came to fuel consumption and took it literally. Bottom line, it’s a lot.

Speaking of drive modes too, the Individual setting (one of five: comfort, sport, sport plus and snow) is the only one you need. Comfort dulls the throttle response and should be called ‘buy a GLS350’, sport is pointless and sport plus only good to demonstrate why you should never use it due to the change to stiff suspension settings.

With this active, the car tends to thump over every surface change and you lose the comfortable nature of a luxury SUV.

Set up Individual with sport plus performance and comfort suspension, and you get the full complement of planet-rotating power, but with a comfortable suspension tune so you can’t feel any consequences of your actions.

You can monster around, gliding over the dreams of people less important than you, chilling your frappacino while receiving a massage, your only decision, where next to fill up.

Look, the 2017 Mercedes-AMG GLS63 might not be a very sensible car, in any measurable way… but it is a great car in every measurable way. Just like that school bus.

The sixty-three makes up a smidge over eight per cent of all GLS sales (93 GLS63 sold in 2016 against 1129 GLS total).

That’s eight per cent of people who care not about trivial things like value or economy, but instead feel they need to be the ones who keep the dream of a drag-racing school bus alive.

There is no point or need for a car like this, and that is what makes it so much fun.

The only thing that would make it better (and yet even more stupid) is a GLS65 V12 version – oh yeah.

Luckily, there might just be a Maybach version on the way...

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