New Mercedes-AMG A 45 S gets pushed to record-breaking 490 hp, 540 Nm

Enthusiasts put the just-launched AMG A 45 S 4MATIC+ (W177) to a Nürburgring test a couple days ago that it essentially failed, coming behind the maxed-out Renault Megane and Honda Civic. Things may still improve with the latest ECU tune from RaceChip.

For those of you who have missed the news, the Mercedes-AMG A 45 S already ships with the world’s strongest mass-produced four-cylinder engine. Called M 139, it churns out up to 421 hp (314 kW) and up to 500 Nm (39 lb-ft) of torque. This enables the new A 45 S to sprint 0-100 km/h (0-62 mph) in 3.9 seconds and max out at 270 km/h (168 mph, electronically capped). Unfortunately, not even this kind of engine proved enough for dominance on the ‘Ring.

RaceChip now offers its GTS Black Tuning Box for the model, which you can install to raise the power output to around 490 hp (365 kW). The torque simultaneously goes up to 540 Nm (398 lb-ft). You may also opt for a cheaper RaceChip RS, which grants comparable 479 hp (357 kW) and 533 Nm (393 lb-ft). The problem is, no more than 405 hp (302 kW) reaches the wheels even with the best tune applied, suggesting serious transmission-related power loss. Could it be something for tuners to fix later on?