The turbo-four terror.
The sheer output and potential of the hand-built, M133 turbocharged inline-four AMG engine continues to amaze. Even in stock form, it cranks out an impressive 381 horsepower like it’s no big deal. But, after the team at Posaidon got their hands on it and created the A45 RS485+, it becomes a turbo-four terror.
The goals that Posaidon had for the 2.0-liter engine were too high for the standard turbocharger to handle. So, they replaced it with a new ball bearing race-spec turbocharger with larger turbine and impeller wheels, and scroll housings to produce the desired increase in boost pressure. More air is drawn into the turbocharger thanks to a low-restriction air filter and higher efficiency intercooler. To get all the exhaust gasses out, a bigger flow-optimized stainless steel downpipe with optional 200-cell catalytic converter are used with the factory AMG exhaust system.
After the hardware was installed, Posaidon gave the A45 RS485+ a full ECU tune as well as a tune for the seven-speed dual-clutch transmission to accommodate for the added power. That resulted in a total of 500 horsepower and 409 lb-ft. of torque from the 2.0-liter turbocharged inline-four. Accelerating to 62 mph from rest now takes just 3.5 seconds and top speed is all the way back at 196 mph.
While acceleration is clearly no problem for the Posaidon A45 RS485+, the German tuning company took steps to ensure that braking wasn’t either. A new front brake kit that includes six-piston calipers biting down on 365 x 34 mm ventilated steel discs with stainless steel lines allow the hot hatch to decelerate with ease.
While Posaidon decided to showcase its upgrades on the A45 RS485+, the engine upgrades are also available on all other Mercedes-Benz models with the M133 engine like the CLA45 and GLA45 AMG models.
Posaidon A45 RS485+ Specifications
Displacement: 2.0 liters
Number of Cylinders: Inline-four
Maximum Horsepower: 500
Maximum Torque: 409 lb-ft. / 555 Nm
-ECU and Transmission tune
-Stainless steel downpipe with 200-cell catalytic converter
-Revised air intake system
Acceleration 0-62 mph: 3.5 seconds
Top Speed: 195.7 mph / 315 km/h
Posaidon A45 RS485+ Gallery