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Mercedes-AMG A45 Review: rise of the hyper-hatch

By Ash Westerman, 31 Jul 2019 Reviews

Mercedes-AMG A45 Review

Hyper-hatch brings a manic advance from the rear

Overall Rating

5 0 5

Plus & Minus

  1. Plus Engine; dynamics, possible rear-drive bias; cabin and tech

  2. Minus edgy low-speed ride; steering modes not switchable; tyre noise

  3. The Wheels Verdict: New A45 improves on its predecessor by every measure, then shifts the hot-hatch game by virtue of the available rear-bias of the drivetrain. The engine gives the car a properly frenetic character when driven hard, but the dynamic envelope provided by the advanced systems make it easy to exploit everything the car can deliver. There’s the expected trade-off in terms of noise and comfort, but they’re not unreasonable in light of what’s on offer.

  4. What is the Mercedes-AMG A45?

  5. The smallest yet angriest offering from Mercedes-Benz’s high-performance division, the A45 is a five-door hatchback that takes the hot-hatch formula to a new level.

  6. Read next: BMW 1 Series won't chase Mercedes-AMG's A45
  7.  

    Why we're testing it

    It’s due in Australia early 2020, so we were hyped to see how it compares to its circa-$18,000 cheaper sibling, the AMG A35. Jarama racetrack near Madrid is also always worth a visit. 

  8. Mercedes-AMG A45 review

    Numbers must be fascinating things if you’re a mathematician, and no doubt plenty of accountants find themselves richly stimulated by a really good-looking spreadsheet.

    But for us car enthusiasts I can’t help wondering if the obsession with numbers has gone too far. Unlike yesteryear when it was all about seat-of-your-pants feel, today's hi-po contenders ask the reviewer to take the Nürburgring lap time, divide it by the 0-200km/h figure, add the often meaningless ADR consumption number, minus the year your mum was born, and bingo, there’s your star rating out of 5 right there.

  9.  

    If you’re cheering in agreement, watch as I now perform a spectacular backflip with double-pike contradiction because no dissection of the new Mercedes-AMG A45 can begin without tossing around a few numbers.

  10. MORE Whichcar TV hot hatch megatest
  11.  

    I’ll try to be concise: this new W177 model, due in Australia in the first quarter of 2020, makes maximum power of 310kW - up 30kW on its predecessor (over 10 percent) - while torque is up 25Nm from 475 to 500Nm total. It does all this – still – from just 2.0 litres.

    That makes its specific power per litre of 155kW higher than McLaren achieves from the Senna’s 597kW 4.0-litre V8 (149kW/litre), and leaves the Porsche GT2 RS, at 135kW/litre, looking like it’s fallen asleep at the gym.  

  12.  

    But more relevantly, in terms of a segment competitor, we should spare a thought for the powertrain team at Audi Sport who are responsible for the 2.5-litre five-cylinder turbo in the current RS3. They were all high-fiving each other when they delivered 294kW/480Nm in 2015. Now, they must be quietly weeping into their lunchtime steins.

    But numbers can only give guidance to a car’s potential. What we really want to know is how the new A45 makes you feel; the real-world level of excitement and driver satisfaction it can provide. Also, in terms of positioning, what it delivers above the A35 that editor Alex Inwood drove most recently over some of Europe’s best Alpine passes (Wheels, August 2019).

     

  13. To explore this, our first taste of the car comes at Jarama racetrack outside of the Spanish capital of Madrid. Random Aussie connection: Alan Jones won the Spanish F1 GP at this 3.85km circuit in 1980 in his Williams, but didn’t get the points due the FISA-FOCA war coming to a head as the rival bodies battled for control of Formula 1 at the time.

    Point is, it’s a proper old-school circuit, with ample elevation change and limited run-off. It’s also hotter than Satan’s sauna during our visit, and a track temp in the mid-30s is not what turbo engines nor road tyres thrive on. And yet the A45 swats you straight between the eyes with its engine.

  14. Read: 2020 Mercedes-AMG A45 S: how it’s moved the game on
  15.  

    On paper, the point of peak torque – 5000-5250rpm – makes it appear that this M139 engine could be a bit peaky, and therefore lag-prone, but the opposite is true. The torque curve is like a flat-earther’s tilted diagram of our planet, and ensures there’s around 420Nm from 2500rpm, so it feels primed and interested from about then and quickly turns muscular, fizzy, and wickedly effervescent in the midrange. On the boil, it’s properly frenetic, yet retains linearity in the pull right through to peak power at 6750rpm, and there’s only a tiny tapering as the needle hits 7000rpm for the new eight-speed dual-clutcher’s change-up point. AMG engineers claimed they wanted an ‘atmo-style’ power delivery, and, thanks to the level of technical sophistication they’ve crammed into this donk, it feels as though they’ve nailed it.

  16.  

    The 0-100km/h claim is a blistering 3.9sec; I’m a little doubtful, even with the Race Start system, that it’s achievable. Regardless, the way the car hooks up and bolts from a standstill will leave no new owner quibbling about a couple of tenths of a second.

    It’s also very handy at decelerating. The brake discs are larger all round than those fitted to the A35, with the fronts (360mm) clamped by six-piston callipers. The pedal is on the long side in terms of travel, but all of it is useful, and there’s massive stopping power when you really hammer them on track, with barely any fade. 

    As for handling balance, the A45’s strongest inclination is to retain neutrality. Of course the front end will get pushy on track if you really bully it, but mostly the chassis responds to the throttle with calm docility, slightly at odds with the freneticism of the engine.

  17.  

    In fast road driving, it still feels predominately front-driven, due to that fact the steering wheel twitches as the front tyres are tasked with deploying torque. Concentrate hard on steering feedback and traction, and you can sense torque being sent rearward. The system is claimed to be able to channel 100 percent to either axle, but that’s very theoretical; it’s closer to 50-50 in road driving.

    The big news is you don’t need the newly introduced Drift mode to enjoy power oversteer. Race mode, with ESC off, will do it, with the dynamic advantage of leaving the front end able to also assist with traction. The caveat is that you really need to tip the car into the corner hard and early, ideally on the brakes to initiate the rotation of the rear, otherwise there’s a medium-thickness layer of understeer to drive through. Once you’re through this, the torque split gets busy feeding the rear axle, and a dab hand can hold big smoking power slides from apex to exit.

    Sure, we first saw the slightly incongruous sight of what’s clearly not a fundamentally rear-driven layout tearing the back treads apart in the Ford Focus RS, so maybe the A45’s ability to do just this shouldn’t be all that startling. But during the lunch break when I spot an AMG instructor chucking it in and lighting it up for a video crew, I just stare transfixed and spontaneously start applauding. The power-sliding hatchback! It’s like watching a dog that can bark Happy Birthday, only much more fun, and with less novelty factor.

  18.  

    The gearbox is mostly excellent, just not quite as instantaneous with its shifts as the best dual-clutchers like Porsche’s PDK. There’s a few milliseconds' delay when you’re really on it and manually plucking for downshifts, but otherwise it’s ultra quick-witted to respond in auto mode when mapped to Sport+. And moving to eight ratios from the previous A45’s seven means top gear is sufficiently tall to drop revs to 1550rpm when you’re pegged at a 110km/h cruise, benefiting economy. 

    As for that cruising ability, the two-mode exhaust in Dynamic skilfully avoids the frequently encountered problem of droning. Its effects are relatively subtle at steady-throttle highway speeds, but it does add a rich timbre under load and really emphasise the manic engine character as the revs swing past 4500rpm. Snap the throttle shut as you jump on the brakes and there is a bit of percussion from the tailpipe, but it’s not the crazy-loud volley of pops and bangs I was expecting. Blame ever-tightening noise regs. To attempt to skirt around this, AMG has added a sound-symposer system that takes actual exhaust acoustics (not a simulation) and pipes them through the audio system. Bastian Bogenschutz, head of product planning for Mercedes-AMG compact cars, explains that stricter regulations mean  the company has had to “employ other methods to deliver the emotive aural experience AMG customers are seeking.”

  19.  

    That’s not the end of the caveats, either. The steering is quick at 2.4 turns lock-to-lock, and its electro-mechanical assistance is controlled by one of two maps – light and, er, not light. Sadly, these can’t be separated from the suspension set-up, so if you select Sport or Sport+ for the extra body control they provide in hard driving, you get mandatory heavier steering. For me this is a shame, because I much prefer the lighter, more nuanced feel delivered in the Comfort mode. Plenty of drivers won’t agree and will like the more meaty connection; I’m just not one of them. At least we can all agree on how slack-free and direct the steering response is, and the intuitiveness and precision with which you can place the car when having a crack on narrow backroads.

    As for the ride, the subframes are now bearing mounted, to reduce the squish of rubber bushings. Obviously this is great for enhancing the chassis responsiveness and driver connection, but it comes at a refinement cost. Sharp edges are prone to clanging into the cabin, and the tyres seem eager for you to know about every surface irregularity. On coarse-chip, the inherent range-wide A-Class issue of tyre noise is no different here in the A45, but it is very surface-dependent. In Spain it was less raucous, but unfortunately, Aussie roads seem to be mostly built from the stuff that makes the tyres so vocal. 

    Other niggles? The column-mounted gear sector is the same plastic as the indicator stalk, yet one is for an ancillary function, the other for the fundamental act of selecting the direction of travel. This seems all kinds of wrong. And the MBUX voice recognition can be flaky and doesn’t have the deep-menu smarts that would make it more useful. 

  20.  

    But back to the involvement question. After Inwood ragged the A35 amid snow-capped peaks, he struggled to form a real emotional connection with that car. Fast, grippy and capable, sure, but did it make you want to give it a slow, loving session with the chamois even when it’s still mostly clean? Not quite.

    So where does that leave its circa $18K more expensive big brother? For me, the A45 makes its central case both in the sheer poke of its engine, and the sophistication of its AWD system. Together, they give you a level of driver engagement that’s unlike any other hot hatch on the market (now-departed Ford Focus RS excepted), and, if you boil it down, actually not all that hot-hatch-like.  

    But we still need to resist the temptation, as power busts through the 300kW barrier, to get too caught up in the whole ‘hyper-hatch’ thing. Fact is, the new A45, despite being redesigned from scratch, doesn’t completely rewrite the formula. Instead, it takes the fundamentals established by its predecessor – traction, pace, and practicality of the bodystyle – and ratchets them up by several notches to reassert its superiority. Factor in its ‘advance from the rear’ dynamic bias, and it’s clear the most persuasive things about the angriest baby AMG are not really numerical at all.  

  21. Mercedes-AMG A45 vs rivals

    Audi RS3, BMW M2 

Mercedes-AMG A45 Specification

  1. Model: Mercedes-AMG A45 S
    Engine: 1991cc 4cyl, dohc, 16v, turbo
    Max power: 310kW @ 6750rpm
    Max torque: 500Nm @ 5000-5250rpm
    Transmission: 8-speed dual-clutch
    Weight: 1550kg
    0-100km/h: 3.9sec (claimed)
    Economy: 8.3L/100km
    Price: $85,000 (estimated)
    On sale: Q1 2020