Stage 1 on a 381PS A45 (W176, 2015 to 2018) is worth around 420PS and 550Nm on our rolling road. The later W177 A45, which uses the M139 engine at 387PS, goes to about 470PS and 620Nm, and the 421PS A45 S reaches the same. The CLA45 and GLA45 share the engine and tune to the same figures in their own bodies. All of it is software only, and every car is proven on the dyno here in Maidstone before it leaves.
Questions we get asked
How much power does an A45 AMG make at Stage 1?
The 381PS W176 car goes to around 420PS and 550Nm. The 387PS W177, which uses the newer M139 engine, goes to around 470PS and 620Nm, and so does the 421PS A45 S. The older 360PS W176 reaches about 400PS and 550Nm.
Do the CLA45 and GLA45 make the same as the A45?
Yes. They are the same engine in different bodies at the same state of tune, so they tune to the same figures. The only real differences are weight and gearing, which change how it feels rather than what it makes.
What is the difference between the M133 and M139 engines?
The M133 is the earlier 2.0 turbo in the W176 A45 up to 381PS. The M139 replaced it in the W177 from 2018: the engine is turned around, the turbo is a twin-scroll roller-bearing unit and it runs a much higher injection pressure. The M139 has more headroom and that is why the later cars gain more.
Do I need the gearbox tuned as well?
Not for Stage 1. These cars use a dual-clutch gearbox with its own torque limiter. If you are going beyond Stage 1, the gearbox software raises the limiter, sharpens the shifts and stops it changing up on its own in manual mode.
Is it road legal and will it pass an MOT?
Stage 1 changes no hardware. The catalyst and every emissions component stay exactly as they are, so the car remains road legal and MOT-ready, and we keep your original file so it can be returned to standard.
Will a remap affect my Mercedes warranty?
A main dealer can detect a remap and may decline an engine or drivetrain claim as a result. We hold your original file and can put the car back to standard before a dealer visit, and we offer an optional engine warranty on Stage 1.
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