Mercedes-Benz A-class gets the AMG treatment

The Mercedes-Benz A45 AMG packs a 330-hp four-cylinder engine.

Mercedes-Benz has confirmed limited details about its most affordable performance model to date, the A45 AMG. 

Set to go on sale in Europe in early 2013, the rival to the Audi RS3 and the BMW M135i sits at the top of the third-generation A-class lineup. The price, although not yet officially revealed, is expected to start at about 50,000 euros, or $62,400 at current exchange rates).

One of three new compact models confirmed by AMG boss Ola Kallenius, the A45 AMG is not planned to be sold in North American. Its mechanical package will, however, appear in upcoming CLA45 AMG and CLA45 AMG Shooting Brake models that are set for U.S. sale in 2014. 

The A45 AMG is the first series-production AMG model with a transversely mounted engine. The A45 AMG runs a heavily tuned version of Mercedes-Benz's turbocharged 2.0-liter four-cylinder gasoline engine from the standard A250 Sport, which goes on sale in Europe in September. With a specially developed free-flow cylinder head and unique induction system the engine, designated M270 Evo, is claimed to deliver 330 hp and what AMG describes as "maximum torque significantly above 400 Nm (295 lb-ft)."

Developed at AMG's Affalterbach engineering headquarters on the outskirts of Stuttgart, the new engine is the most powerful four-cylinder ever placed in a Mercedes-Benz production model.

"Our goal right from the very start was to match the output of the larger turbocharged 2.5-liter five-cylinder engine used by the RS3," says Tobias Moers, head of development at AMG. At just 375 pounds, the engine is also said to be significantly lighter than rival four-cylinder performance engines.

For comparison, the Audi RS3's engine delivers 335 hp and 332 lb-ft torque, while the BMW M135i, which is powered by an uprated version of the N55 turbocharged 3.0-liter six-cylinder unit, pushes out 316 hp and 332 lb-ft of torque. 

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 multiplate clutch to all four wheels. To provide the car with rear-wheel-drive AMG handling traits, the engine's torque is delivered primarily to the rear wheels under load.

No performance claims were made in a secretive media preview of the A45 AMG in Affalterbach on Tuesday. But Mercedes-Benz insiders suggest that the car will match the claimed 0-to-62-mph time of the M135i, which BMW puts at 5.1 seconds for the six-speed manual version. Top speed is limited to 155 mph.

The inclusion of fuel-saving features such as stop/start and brake-energy recuperation has Mercedes-Benz claiming that the A45 AMG will be the most economical car in the hot-hatch ranks.

In a bid to provide the A45 AMG with class-leading dynamics-including what one AMG insider described to Autoweek as "the highest corner speeds among its rivals"-the AMG engineering team devised a largely unique chassis setup and tested it extensively on the road and at the Nürburgring. 

The basic components of the MacPherson-strut front and multilink rear suspension are carried over from the A250 Sport, but items such as the bushings used to attach it to the body structure have been greatly altered. Other changes include wider tracks, firmer springs and dampers, larger-diameter antiroll bars and a reduced ride height. The standard electromechanical steering system was reworked for added on-center sensitivity and a meatier feel, while the brakes were upgraded with larger cross-drilled and vented discs and more powerful calipers.

As with other recent AMG models, the A45 AMG also receives a three-stage electronic stability program (ESP) that includes a sport-handling mode that allows you to turn the electronic safety net off completely. 

"Our goal is to build the most dynamic, most powerful and at the same time most efficient four-cylinder series production compact car," says Kaellenius. 

The A45 AMG is differentiated from other A-class models by an extensive body kit. Included is a deeper front bumper, an altered grille, widened front fenders, carbon-fiber-look exterior mirror housings, wider sills underneath the doors, a prominent spoiler atop the rear hatch and new rear bumper with an integrated diffuser element and characteristic chromed tail pipes. Inside, the car receives an upgraded interior with unique front sport seats and more upmarket trims, including a carbon-fiber-look panel for the dashboard.

The A45 AMG, whose name celebrates the 45th anniversary of Mercedes-Benz's performance-car division, forms an integral part of a new model strategy mapped out by Kaellenius.

Named "AMG Performance 50," the plan will see at least eight, possibly nine, new models added to the AMG lineup within the next five years.

Along with the A45 AMG, Mercedes-Benz is also putting the finishing touches on the mechanically identical CLA45 AMG, a swoopy sedan previewed by the Concept Style Coupe revealed at the recent Beijing motor show.

Other new AMG models include the recently revealed G63 AMG, SLS AMG Black Series, CLS63 AMG Shooting Brake, CLA45 AMG Shooting Brake, a possible GLA45 AMG and two new S-class-based models set to based on the new W222 model due out in 2013.