AMG's normal philosophy is to take a big Merc, stuff a huge V8 in it and adorn it with carbon bits and pieces, enormous wheels and race tuned suspension. The A45 AMG must have been an altogether different challenge. For a start it's an A-class AMG, a small car, the smallest in the whole Mercedes range and a V8 won't fit in the engine bay.
So, instead AMG have taken a 2 litre, 4 cylinder engine, fitted a twin scroll turbocharger and stuffed as much power as possible into it. Similar in philosophy to the old Evo/Impreza power wars.
The results are quite spectacular. From it's relatively tiny 2 litre the AMG 45 AMG produces 360hp and 331 lb ft or torque. And it's got 4Matic four wheel drive. And it does 40.9mpg. And it's a hatchback. And it doesn't look like a bulldog chewing a wasp.
The 0-62mph run takes 4.6 seconds and top speed is limited to 155mph. The A 45 AMG even comes in a low tax bracket with 165 g/km of CO2. The high power ratio is achieved through lots of AMG trickery. The twin scroll turbo has a maximum charge pressure of 1.8 bar which uses exhaust gas back pressure from low revs to reduce turbo lag.
In order to try and get round the awkward quietness of a small capacity 4 cylinder that uses a high pressure turbo, Mercedes have opted to fit a continuously adjustable exhaust flap, similar to that fitted to the SLK 55 AMG, to share the A 45 AMG's aural treats with the occupants and surrounding population. A quiet AMG isn't a true AMG. A much better philosophy than playing engine noises through the stereo, like BMW do in the M5.
The only gearbox available is a DCT 7-speed semi-automatic which Mercedes unfortunately describe as being directly flange-mounted on the transversely installed engine. It double declutches and uses software from the SLS AMG to create an almost uninterrupted transmission of power from the engine.
Drive to the road is via Mercedes' 4Matic all wheel drive system. Isn't it about time they came up with a better name? 4Matic sounds so 50s, although it was first introduced in 1985 on the W124. During normal driving the A 45 AMG sends it's power to the front wheels but floor the throttle, lose traction, and it splits the torque 50:50 front and rear.
The A45 AMG also gets AMG sports suspension (multilink front and rear), twin spoke AMG alloys, speed sensitive steering, AMG brakes, AMG touches to the bodywork and lots of hand-stitched leather in the cabin.
The A 45 AMG hits dealers in July and costs €49,682 in Germany, which is £42,900 or $64,600 US
