Affalterbach's second-gen, hardcore compact SUV outed with 310kW punch, launches in Australia by Q4
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The second-generation Mercedes-AMG GLA 45 S mega-SUV has been revealed ahead of its world premiere in Geneva next week and Australian arrival in the final quarter of 2020.

Like its A45 AMG sibling, the hottest GLA is powered by the company's latest ballistic turbocharged four-cylinder engine, made by hand at AMG’s Affalterbach headquarters.

The new ‘M139’ donk makes a peak of 310kW and 500Nm in the AMG S model that’ll be sold here (don’t worry about the 285kW/480Nm base GLA 45 version, which we won’t get). That’s up 30kW and 25Nm on the old one.

For context, its outputs better the 2.5-litre five-cylinder turbo used in the Audi RS Q3 from Ingolstadt, which makes 294kW/480Nm. That car really shapes up as the AMG’s nemesis.

AMG claims a 0-100km/h sprint time of 4.3 seconds, which is 0.4 sec slower than the lower and leaner A45, and a restricted top speed of 270km/h.

The engine has all sorts of cool features, such as rear-positioned 2.1-bar twin-scroll turbo and exhaust manifold, two-stage piezo injectors, an electronically controlled wastegate (exhaust relief valve), and multiple water pumps to cool the cylinder head and crankcase separately.

The cylinder linings themselves are coated in a patented Nanoslide mirror-like coating trickled down from F1 to reduce friction on the variably controlled valves.

But the coolest bit in this writer’s view is the technology used to lend the turbo engine “response compared to a normally aspirated engine”.

This idea is called torque shaping, and at its core it means moving away from a flat table-like torque curve and instead delivering this maximum torque higher up the rev band, between 5000 and 5250rpm, well on the way to its 7200rpm redline. Max power hits at 6750rpm.

This theoretically gives the engine a “more emotive driving experience” because the engine is more free-revving. A quick look at the torque graph shows that there is still north of 400Nm before 2000rpm.

Like AMG’s BiTurbo V8 engines, the M139 is assembled by hand from a delivered block, under its ‘one man, one engine’ principal. This means one person builds the engine over a period of 2.5 hours start-to-finish before it goes to bench testing, and affixes a signed build plate.

The standard transmission is an eight-speed DCT with the ability to double-downshift. Depending on the selected AMG driving mode, the car takes on different accelerator and gear shift mapping. The ‘box can also decouple from the wheels when gliding downhill.

Control of the drive torque to the front and rear axle, and between the two rear wheels, is electromechanical. The AWD system’s brain uses data from speed, lateral movement, and the relative rotational speed of each wheel. It has a more rear-biased mode available.

The brand new suspension comprises struts at the front and four linkages at each rear wheel, while the adaptive dampers have multiple different levels of stiffness controlled by button or dial. There’s also electromechanical AMG speed-sensitive power steering with varying resistance.

The brake package comprises 360 x 36mm front discs with six-piston fixed calipers, and 330 x 22mm single-piston (floating) stoppers at the rear. The car’s brain can also tell the mechanicals to nip the inner rear wheel in corners.

There are six AMG Dynamic Select drive programs called Slippery, Comfort, Sport, Sport+, Individual and Race that modify the throttle, shift times, AWD control, ESP, and suspension stiffness. There are also two active exhaust sound options with in-cabin ‘enhancement’.

AMG “extensively reinforced” the body shell and changed the track and camber. An aluminium plate bolted underneath the engine, known as the "shearing plate", further increases the torsional rigidity at the front end. Diagonal struts front and rear of the underbody ditto.

Styling changes include ‘powerdomes’ on the bonnet, AMG-specific radiator grille, LED high-performance headlights, different front splitter, five-spoke 20-inch wheels (optional 21s), two 82mm round tailpipes, two-piece tail light clusters, and roof spoiler.

Inside you get faux leather and micro-fibre bucket seats (or various leather with aluminum trim edges), and a nappa leather/micro-fibre wheel with contrasting topstitching, a coloured 12 o'clock marking, AMG steering wheel buttons and logo, steel paddles, and ambient lighting.

The MBUX infotainment system comes with a gear speed indicator, warm-up timer, g-meter, race timer and engine data readout. AMG Track Pace software continuously monitors more than 80 vehicle-specific data points and displays lap and sector times.

Specific display elements are shown in green or red, so the driver is able to see at a glance without reading numbers whether they are currently faster or slower than the best time. Acceleration and deceleration values can be measured and saved.

The MBUX Augmented Reality function also shows you the ideal line on a stored racetrack on the multimedia display or optional display, allowing the driver to improve lap times “with a virtual instructor on board”.

Australia

The GLA 45 has always been a top-seller locally, and the penetration of tuned-up Mercedes’ is among the highest here out of any market.

“Local showrooms will offer flagship S variants exclusively. At this stage we expect vehicles to begin arriving in the last quarter of this year. Pricing and local specifications will be available closer to that time,” Mercedes-Benz Australia says.