Set to go on sale in early 2013, the Audi RS3 and BMW M135i rivaling hatchback sits at the top of the new third-generation Mercedes A-class line-up at an unconfirmed price that is expected to start at around £35,000 in the UK.
The first series production AMG model with a transversely mounted engine runs a heavily tuned version of Mercedes-Benz’s turbocharged 2.0-litre four-cylinder petrol unit, as used in the standard A250 Sport set for UK sale by the end of the year.
With a specially developed free flow cylinder head and unique induction system among a myriad of other power boosting modifications, the M270 Evo designated unit is claimed to deliver 330bhp and what AMG describes as "maximum torque significantly above 295lb ft".
Developed in partnership with the German car maker’s High Performance Engine offshoot based in Brixworth, England, the new engine is the most powerful four-cylinder ever placed in a Mercedes production model.
"Our goal right from the start was to match the output of the larger turbocharged 2.5-litre five-cylinder engine used by the RS3," says Tobias Moers, head of development at AMG.
By way of comparison, the RS3’s EA255 engine delivers 335bhp and 332lb ft torque, while the M135i, which is powered by an uprated version of BMW’s N55 turbocharged 3.0-litre six-cylinder unit, pushes out 316bhp and the same 332lb ft.
As first revealed by Autocar, the A45 AMG channels its drive through a seven-speed dual clutch gearbox and, in a layout that mirrors that of the RS3, a specially tuned Haldex-style multi-plate clutch to all four wheels.
To provide the new car with typical rear-wheel drive AMG handling traits, the engine’s torque is delivered primarily to the rear wheels under load.
No performance claims have been made prior to the A45 AMG’s official unveiling at AMG’s Affalterbach headquarters in Germany this week, but Mercedes-Benz insiders suggest it will match the claimed 0-62mph time of the M135i, which BMW puts at 5.1sec for the six-speed manual equipped version.
The inclusion of fuel saving features such as automatic stop/start and brake energy recuperation also has Mercedes-Benz claiming the A45 AMG will be the most economical car in the hot hatch ranks.
In a bid to provide the price leading AMG model with class leading dynamics – including what one AMG insider described to Autocar as "the highest corner speeds among its rivals", AMG’s engineering team has provided it with a largely unique chassis set-up – the likes of which has undergone extensive testing both on the road and at the Nürburgring.