Turbocharged motor with 387hp and 421hp set to feature in imminent A45 and CLA45.
That’s over 200hp per litre!
That’s right, which is why Mercedes-AMG is billing its latest 2.0-litre petrol-turbo as the most powerful four-cylinder engine to be made available in series production.
Due to appear in the imminent next-gen A45 hatch and CLA45 coupe-cum-sedan, the new M139-tagged motor will yield two power outputs, one for the regular model and the other for the go-faster S.
The regular variant produces 387hp at 6,500rpm, while the S generates 421hp at 6,750rpm. Both use a single twin-scroll turbocharger but with different boost pressures of 1.9 bar and 2.1 bar accordingly.
But it’s the power delivery that’s claimed to impress, according to Mercedes-AMG. The lesser version makes 480Nm at 4,750-5,000rpm and the greater one 500Nm from 5,000-5,250Nm.
Mercedes-AMG says this kind of torque curve gives a more “emotional power delivery” with a gradual build-up in rush at high revs. The redline of the hand-built M139 is 7,200rpm.
The previous M133-coded 380hp motor made 475Nm from 2,250-5,000rpm. And yes, real-world tests have proven that this diesel-like plateau didn’t make the A45, CLA45 and GLA45 particularly fun in performance terms.
I see. How does it compare to the “35” models?
The latest A35 and CLA35 use a different motor called M260. It has the turbocharger and exhaust manifold placed in front (between the motor and radiator).
The M139 is also transversely laid out but sees those components placed behind (between the motor and firewall). Mercedes-AMG says this helps for a lower end of the bonnet aiding on better aerodynamics.
Naturally, the A35 and CLA35 have lower outputs of 306hp at 5,800-6,100rpm and 400Nm at 3,000-4,000rpm. Both have 0-100kph figures of 4.6sec and 4.7sec respectively.
As the previous-gen A45 managed an acceleration time of 4.2sec, expect the successor with the new M139 motor to better that, or even dip under the four-second barrier for the first time. Now, that would be a real super-hatch!
Cool! How will BMW respond with its new 1 Series?
That remains an interesting point. Just recently, BMW has revealed the all-new 1 Series hatchback with the same front/four-wheel drive and transverse engine matrix as the A-Class.
On top of the range is the M135i with xDrive all-wheel drive (4Matic in Mercedes speak) with a 2.0-litre petrol-turbo producing the same 306hp as in the A35.
Of course, making a match for the A45 isn’t difficult in engineering terms but probably on the marketing side of things.
BMW’s current badge strategy means that anything more powerful than the M135i and engineered with the full-fat M treatment should be called M1.
However, M1 is the name of an iconic mid-engined Bimmer made in the late 70s. That’s why the name has never been used again and BMW had to resort to the 1M badge for the past 1 Series Coupe on steroids.
Two other mega hatchbacks that are soon to be renewed in next-gen forms with power nudging 400hp include the Audi RS3 and Volkswagen Golf R Plus.
