The new Mercedes-AMG A45 isn’t just fast, it’s enjoyable too – but it’s not cheap either

The old Mercedes-AMG A45 was a perfect example of high performance not necessarily equating with high levels of fun. It was ballistic in a straight line and undoubtedly offered high levels of grip, but it was low on interactivity, and thanks to a firm ride, crashed and jiggled too much on the sort of roads where other hot hatchbacks excel.

Things were promising then when Mercedes-AMG launched the A35 earlier in the year, based on the latest fourth-generation A-class. Here was a car that could go toe-to-toe with one of the best in class, VW’s Golf R. With more power, and even more focus in its engineering, does the latest A45 – tested here in high-output A45 S trim – get even closer to the mark?

Engine, transmission and 0-100 time

Like the A35 below it, the new AMG A45 uses a 2-litre turbocharged four-cylinder engine, eight-speed dual-clutch transmission, and 4Matic all-wheel-drive system, but beyond that the similarities diminish.

For a start, AMG has extracted 310kW in S trim (284kW as a non-S) from its latest 2-litre unit, at 6750rpm, and it delivers 500Nm of peak torque (non-S 480Nm) between 5000 and 5250rpm. This gives it the highest output per litre of any 2-litre engine in production, and as you can imagine, this has required quite some engineering to achieve.

> Click here for our review of the Volkswagen Golf R

The upshot is the ability to sprint to 100kmh in 3.9sec, or three-tenths quicker than the old A45 – remember when these kind of numbers were the preserve of supercars? – with a top speed limited to 270kmh in A45 S trim.

Power is sent to all four wheels, as before, though this time around AMG has made use of what it calls AMG Torque Control, using a pair of multi-disc clutches at the rear axle to divert power as required to each rear wheel, neutralising understeer and, if Race mode and the manual transmission mode are selected, enabling a new drift mode.

Technical highlights

So, that engine. It’s effectively all new, twisted 180 degrees around compared to the 2-litre in the A35, so the exhaust ports and turbocharger are between the engine and firewall, and the intake side is towards the front of the car, to the benefit of air flow.

The turbo itself uses roller bearings for reduced friction, and has divided ducts to prevent exhaust pulses disturbing each other as they flow through the turbine. There’s an electronically controlled wastegate, and the turbo is cooled by water, oil and air – the latter aided by special ducts in the engine cover, a technique learned from the hot-V V8s used further up the AMG hierarchy.

Then there are reworked valves, two-stage fuel-injection, two different water pumps to meet the different cooling requirements of the head and block, a two-stage intercooler to meet the demands of road and track use, and a baffled sump. It’s also a legitimate Affalterbach ‘one man, one engine’ unit, assembled by hand.

AMG has stiffened up the A-class shell with underbody bracing and several extra gussets welded in key areas, subframes are rigidly mounted, and all A45s use new frequency-selective adaptive dampers, the behaviour of which can of course be adjusted from inside the car.

What’s it like to drive?

Our yellow A45 S test car looks, colour aside, surprisingly subtle compared to the last A35 we drove. That car had the factory aero pack, an option again available on the A45 but not fitted to this particular car. Choose a more muted shade and the A45 could fly completely under the radar, which will surely appeal to some customers.

There’s little more drama once inside, beyond the showroom flash of the large two-screen layout. It remains one of the best cabins in the class for design and it’s pretty good on functionality too – even the voice controls for the MBUX infotainment system work well, though you’ll have to try to avoid saying ‘Mercedes’ if you don’t want it to pipe up in the middle of conversations.

The AMG seats and Alcantara wheel are pleasing touches (and the former prove very comfortable), but a few squeaks and rattles from the test car suggest Mercedes still has a little way to go to match the best in class for build quality.

It’s already there for performance though. Twist the steering wheel-mounted drive mode dial straight around to Sport+ to call up the more aggressive driving modes, steering weight and exhaust valving, sink your foot to the carpet, and there’s just a momentary pause before you hurtle forward, accompanied by a loud exhaust blare and crackles with every snap of the gearbox and lift of the throttle.

A touch less blare wouldn’t go amiss, actually (some of it is sound artificially piped into the cabin, and it verges on the irritating), but there’s no doubt it’s exciting, and it sets the tone for what is actually a genuinely entertaining hot hatch.

Nope, you didn’t just misread that. The differences to the (already accomplished) A35 are relatively subtle, but as well as adding speed, the A45 engages slightly more and gives the driver a few more options than its less powerful sibling.

Steering is relatively light even in Sport+, but unfailingly accurate, and as you work the Pilot Sport 4 S tyres there’s even a whisper of useful feedback through the rim. Front-end grip is remarkable, from turn-in to corner exit. Only on sections of road polished pebble-smooth does the nose threaten to wash wide, but good balance means this is easily neutralised with a lift, or in some cases, a harder press on the right-hand pedal to wake up the AMG Torque Control differential.

You can do this ludicrously early, the fronts simply digging in and the rear feeding around to lock you to the corner’s radius. Push hard enough and the car will rotate by a few additional degrees, requiring an easily measured input of opposite lock.

The brakes are reassuringly powerful, and while there’s a softness to the pedal at first, the bite is there when you need it. The ride quality seems more than pliant enough for this sort of car (with the usual caveat that warm, dry Spanish roads are rarely the lumpiest of tests), and while refinement does deteriorate on rougher stretches, the A45 plays the cruiser card well too, settling down to a relatively quiet cruise. ANTONY INGRAM