Mercedes-Benz A45 AMG

It's this or a McLaren P1 hypercar...
By Andrew Frankel

Price: £37,845
Engine: 2.0 litres, four cylinders, turbocharged
Power: 355bhp @6000rpm
Torque: 332lb ft @2550-5000rpm
Transmission: seven-speed twin-clutch paddle-shift auto, four-wheel drive
0-62mph: 4.6sec
Top Speed: 155mph
Economy: 40.9mpg
CO2: 161g/km

There is always a frustration when it comes to including the slightest technical detail in the mainstream media. Editors get twitchy at mention of the word "torque", let alone the merits of twin scroll versus sequential turbocharging. At Motor Sport no such issues exist: you guys get this stuff, which is why you'll be able to understand far better than most what an extraordinary new car this new Mercedes A45 AMG really is.

It might be Mercedes' first serious foray into the world of hot hatchery, but this is no token attempt at a presence in a market it has ignored for too long, as its engine will now make clear.

It is a 2-litre, single-turbo, fourcylinder unit and there is nothing remarkable in that. But with twin scrolls, a drainpipe exhaust minimising back pressure, 0.8 bar of boost and a very clever scavenging system, it generates 355bhp. Put another way, if you want to buy a car with an engine that provides more horsepower per litre, put your hand in your pocket, pull out £866,000 and place an order for a McLaren P1 hypercar. The rival BMW M135i uses three litres, two turbos and six cylinders to generate just 315bhp. There is no four-cylinder engine of any size in any production car that generates more power.

Which is impressive. But not as impressive as the way this power is delivered, in one relentless shove from just over 2000rpm to peak power some 4000rpm further round the dial. Despite its inevitably low 8.6:1 compression ratio and all that boost, there is only minimal lag and not the merest suggestion of peakiness. The result is performance unprecedented in the hatchback arena. Making the most of its four-wheel drive and standard launch control, I timed it at 4.3sec to 60mph and 10.6sec to 100mph, numbers some so-called supercars would struggle to match. On the autobahn it barely drew breath as it hammered up to 155mph, whereupon progress was only mitigated by its speed limiter's somewhat rude interruption.

Mercedes also clearly has high hopes for the A45's cornering capabilities, because it hired the brand-new, Hermann Tilke-designed Bilster Berg circuit outside Hanover and then suggested I tried to keep up with Bernd Schneider... who was driving an SLS.

To call the new track a mini Niirburgring is no exaggeration. It's a monster ride, full of blind crests, horrible cambers, wild elevation changes and the biggest drop this side of Laguna Seca's corkscrew. It's the kind of circuit where unchecked body movement will be instantly punished and every flaw in a car's set-up ruthlessly exposed. The ideal weapon would be light, mid-engined and rear-wheel drive. Everything, in other words, the A45 is not.

And exposed it duly was. Although it fled down the straights and proved its brakes to be more than capable of handling its massive power, it generally struggled to find its way into each apex. Its incipient understeer could be countered by flicking the car on a trailing throttle, but often even that was not enough to tempt the nose to hit its mark. It should let you carry speed into the turn in a neutral to mildly oversteering stance and then rely on effectively limitless traction to pull you out the other end, but even if you turn off the electronics that's not a game it wants to play.

Nor is its seven-speed double-clutch transmission quite the paragon it first seems. If you leave it to its own devices, it does a passable impression of a conventional automatic, but when you start shifting yourself its responses become a little inconsistent, not always giving you the upshift you requested and sometimes delaying the downshift for some inexplicable reason. For all but track work it's best to leave it in its sport setting, when it will flick instantly between ratios with a clearly manufactured but nonetheless invigorating rifle crack from the exhausts.

Out on the road, its chassis limitations are far less apparent. Thanks to its relatively compact dimensions, power delivery and that traction, there are many purpose-built sports cars costing several times more that, in reality, would fail to keep up with the A45 along a tight, twisting road. In such circumstances it's never factors like ultimate acceleration or cornering force that determine your pace, but how easy it is to thread through the gaps, the level of visibility around the car and how thoroughly it convinces you that, come what may, it's not going to do anything untoward. In the end it's all about confidence and, on the road at least, there are few that inspire confidence more than this.

But it's still not as entertaining as, say, a Ford Fiesta ST costing less than half the money. This is because the relationship between fast and fun has always been tenuous, at best. On the road you might be less troubled by the A45's tendency to understeer, but the lack of feel from the steering is actually more apparent than it is on the track.

Instead it appeals on a perhaps mature level, one acknowledging that, however much we'd like to spend our time screaming around tracks and rocketing along deserted country roads, reality is somewhat more mundane.

Once you've extinguished your trousers, turned all the settings back to default and driven it like you might on your way to work one dull Monday morning, you will see what Mercedes has actually done with this car. With such a capacity for going absolutely berserk, it's the power and performance that will capture all the headlines, but perhaps the greater achievement is to have tamed such mighty forces to such an extent your passengers need not even know they're there.

For the full effect there are some things you must or, rather, must not do. Do not order the sports exhaust because the novelty of the farting noises will wear off within the hour, leaving you with just an annoyingly loud exhaust. Do not specify the 19in wheels because they spoil the ride, and avoid the 'performance' suspension unless you really do intend to take it on the track. As is so often the case, keeping the car standard — or as its engineers intended it — is best.

Then all sorts of surprises await. First is that it's quite comfortable, thanks to well damped suspension and excellent bucket seats. Engineers at AMG will tell you quite proudly that, in their opinion at least, it rides better than most cooking A-classes. And I'd not disagree. It's quiet, too, thanks to the engine's exemplary part-throttle manners and surprisingly long gears. But it's more than that: it's truly civilised. I liked the woven cloth dashboard, the interior design and the fact that everything that looks like metal really is metal.

Its most serious problem is the price. At £37,845 it's over £7000 more expensive than the BMW M135i, which does have six sonorous cylinders, a standard manual gearbox (not available for the Mercedes) and correct-wheel drive. Then again, the A45 's performance and sophistication are in a different league.

Of the two I'd rather drive the BMW, but as an everyday car for all reasons the A45 AMG is at least as impressive an achievement and, on balance, just about worth the extra.