Alfa Romeo Junior: Engines, Platform, and Engineering – The Complete Guide to 2025

When it comes to the Alfa Romeo Junior , almost everyone focuses on aesthetics, trim levels, and price. But there's much more beneath the surface: a platform shared with other Stellantis vehicles, a latest-generation 1.2-liter three-cylinder mild-hybrid engine, an electric version with a 54 kWh battery , and a steering and suspension setup that strives to maintain the Alfa Romeo character. In this guide, we analyze the technical aspects in detail: how the Junior is made, how the engines and hybrid system work, what's different compared to the "old" Alfas, and what all this means in terms of reliability, driving, and maintenance .

If you are interested in the problems, defects and official recalls side, you can find a dedicated analysis in the linked article: Alfa Romeo Junior – Problems, Defects and Recalls 2025 .

E-CMP / CMP PLATFORM: WHAT'S UNDER THE BODY

The Alfa Romeo Junior is built on the Stellantis Group's CMP/e-CMP platform, a modular foundation designed from the outset to accommodate both internal combustion engines and electric powertrains. It shares the same architecture as the Peugeot 2008, Opel Mokka, Jeep Avenger, Fiat 600, and the latest-generation 208/Corsa small cars.

Translated into practice:

• transverse front- engine with front-wheel drive (and, in the future, possible variants with hybrid 4x4);
• suspension layout typical of the B-SUV segment: McPherson at the front and torsion beam at the rear, optimised by Alfa to give greater driving precision;
• structure designed to be light but with enough space for a 54 kWh battery in the electric versions.

Compared to a Giulia or a Stelvio, which are built on the Giorgio platform with a rear-wheel drive/premium setup, the starting point here is much more "generalist." But it is precisely on the calibration of the steering, suspension, and brakes that Alfa has sought to put its own signature.

DIMENSIONS AND ROAD OVERALL DIMENSIONS

The Junior is positioned in the heart of the B-SUV segment:

• length : about 4.17 m;
• width (without mirrors): approx. 1.78 m;
• height : around 1.53 m;
• step : about 2.56 m.

The result is a car:

• easy to park in the city;
• quite stable at high speed thanks to the wheelbase and the not too narrow track;
• with a trunk among the best in the segment: 415 liters for the hybrid and around 400 liters for the electric one.

1.2 HYBRID 136 HP ENGINE: INSIDE THE STELLANTIS THREE-CYLINDER ENGINE

The most “universal” version of the Junior is the 1.2 Hybrid 136 HP . Technically we have:

• 1.2 turbo three-cylinder engine (1199 cm³), petrol, direct injection;
• maximum thermal power: approx. 100 kW / 136 HP ;
• maximum system torque: 230 Nm (official Alfa Romeo plate data).

This engine is the evolution of the PSA/Stellantis group's EB2 family, which has powered many Peugeot, Citroën, and Opels over the years. This is precisely why it has often been the center of discussion: in the early series, some 1.2 turbo engines suffered from lubrication, timing chain, and injector problems if the oil and maintenance were neglected.

In Junior, however, we are talking about a more recent generation, with updates on:

• thermal management (cooling and operating temperatures);
• lubrication, with specific oils and more “protective” strategies in transients;
• interface with the hybrid system, which relieves the work of the thermal engine during the most stressful phases (restarts, maneuvers, continuous slowdowns).

However, it remains a very powerful engine (a lot of power from a small displacement): for this reason, in practice, it is essential not to improvise with oil, intervals and fuel, as I explain in detail in the article on problems and recalls.

THE 48V MILD-HYBRID SYSTEM: WHAT IT REALLY DOES

The 1.2 Hybrid features a 48-volt mild-hybrid system that's much more advanced than the older "alternator-only" MHEVs. Here we have:

• a P2 electric motor of approximately 21 kW integrated into the e-DCT gearbox;
• a small lithium-ion battery (less than 1 kWh gross) positioned in the floor;
• dedicated power electronics to manage recovery and assistance.

In concrete terms, what does this system do?

• electric starts at low speeds and when manoeuvring (parking, slow-moving traffic);
• help to the internal combustion engine during start-up phases, reducing turbo “gap” and fuel consumption;
• coasting at constant or release gas, with thermals that can switch off and on almost imperceptibly;
• energy recovery during braking, which is stored in the 48V battery.

It's not a full hybrid like Toyota's: you can't travel long distances in electric mode alone, but in the city and in traffic the feeling is of having a car that often "glides" with the combustion engine off and picks up revs much more promptly than a traditional 1.2 turbo.

6-SPEED E-DCT GEARBOX: HOW IT'S MADE AND HOW TO DRIVE

The gearbox is a 6-speed dual clutch (e-DCT6) , also of Stellantis origin, with the electric motor integrated into the gearbox body .

From a technical point of view:

• double clutch in oil bath;
• electronic gear selection with automatic or manual logic (via paddle or lever);
• coordinated management with the 48V electric motor to make gear changes smoother at low speeds.

On the move, when everything works as it should, the feeling is of a change:

• quick to shift up in normal mode;
• quite smooth in “city traffic” thanks to the help of the electric;
• capable of exploiting the medium-rev torque of the three-cylinder engine well.

The downside is that it's a complex mechatronics unit : failures, when they occur, are neither trivial nor costly. For this reason, too, from a reliability perspective, it's important:

• keep software updates up to date;
• don't ignore any jerks, hesitations or warning lights related to the gearbox;
• use the correct fluids (gearbox, hybrid circuit) according to official specifications.

ALFA ROMEO JUNIOR ELECTRIC: 54 kWh BATTERY AND TWO POWER LEVELS

The Junior's electric range revolves around a single battery but two levels of engine power:

• Junior Electric 156 HP : front engine with 115 kW (156 HP) and 260 Nm of torque;
• Junior Elettrica Veloce 280 HP : front engine with 207 kW (approximately 280 HP) and 345 Nm of torque.

In both cases the battery is a 54 kWh gross (approximately 50.8 kWh usable), with 400 Volt architecture and DC fast charging capacity of up to approximately 100 kW.

AUTONOMY AND REAL USE

According to official data and major road tests:

• the 156 HP version gets close to the 410 km WLTP in the mixed cycle, with real-world ranges that vary greatly between city, extra-urban and motorway;
• the Veloce 280 HP , more powerful and high-performance, has a typically lower real autonomy (around 300 km on mixed roads, even less at a constant 130 km/h).

In the city, with careful driving and by taking advantage of braking energy recovery, the electric Junior can be very efficient; on the highway, like all compact EVs, it suffers from the aerodynamics of a B-SUV and the limited battery capacity.

CHASSIS, STEERING AND SUSPENSION: HOW IT STAYS TRUE TO ALFA'S DNA

The challenge for Alfa Romeo was clear: take a platform shared with mainstream models and give it an "Alfa touch" in driving. Initial independent tests have revealed some distinctive features:

• steering is quite direct for the category, with quick response around the centre and good precision;
• suspensions calibrated to keep the car body well supported, without becoming extreme on rough surfaces (however, it remains stiffer than some “comfort oriented” rivals);
• balanced braking , with a fairly well-managed combination of regeneration (on electric and hybrid vehicles) and a traditional system.

We are not at the levels of a Giulia on the Giorgio platform, but compared to many B-SUVs the Junior manages to give that feeling of a “lively front end” that Alfa Romeo fans like, especially in the more powerful electric versions with Veloce trim and larger section tyres.

DIMENSIONS, HABITABILITY AND BOOT SPACE: FROM AN ALFA OF THE PAST TO A MODERN B-SUV

If we compare the Junior with the compact Alfas of the past (145/146, 147, Giulietta) the transition to B-SUV brings clear consequences:

• the driving position is higher , with greater ease of access and visibility in the city;
• the centre of gravity is inevitably higher than that of a traditional sedan/hatchback;
• the trunk is significantly more usable (up to 415 litres), with a comfortable loading threshold and folding seats that bring the volume to over 1,200 litres.

Rear legroom isn't that of a C-segment SUV, but it's more than adequate for a family with children or teenagers of average height. Those taller than 185 cm may notice a slight sacrifice in height/capacity in the versions with the panoramic roof.

JUNIOR VS. “OLD” ALPHA: A COMPARISON OF PHILOSOPHY

Putting a Junior next to a 147 or a Giulietta means comparing two different eras of the car :

• first: naturally aspirated or turbocharged engines with larger displacement, manual gearbox, less invasive electronics, more “mechanical” setup;
• today: downsizing , low-displacement turbo, 48V hybrid or full electric, electronics that govern ADAS, steering, engine and gearbox.

The advantage of this new philosophy is evident in terms of:

• consumption and emissions;
• acoustic comfort in the city (especially on hybrid and electric cars);
• active safety (full ADAS, automatic braking, lane keeping, etc.).

The downside is that the car becomes:

• much more dependent on software and electronics;
• less “pure mechanics” and more complex to diagnose outside the official network;
• more sensitive to the quality of maintenance (right oil, ECU updates, HV battery management).

The Alfa Romeo Junior tries to strike a balance: a groupset platform , yes, but with a more engaging steering and suspension setup than average. Those seeking the sensations of a 75 or a 156 will inevitably find a different world; those coming from generalist B-SUVs will find a livelier and more communicative ride.

CONCLUSIONS: FOR THOSE WHO MAKE SENSE THE HYBRID AND FOR THOSE WHO MAKE SENSE THE ELECTRIC

From a purely technical point of view, the Junior range can be summarised as follows:

• 1.2 Hybrid 136 HP :
  • ideal for those who spend a lot of time in the city and out of town, with some stretches of motorway;
  • interesting fuel consumption if you use the 48V well and drive smoothly;
  • requires attention and rigor on maintenance (oil, updates, recalls).
• Junior Electric 156 HP :
  • suitable for those who have home charging and short/medium daily distances;
  • very pleasant for its silence and readiness in the city;
  • Real autonomy sufficient for most mixed uses, but to be evaluated carefully if you do a lot of motorway driving.
• Junior Electric Fast 280 HP :
  • more emotional version, with great performance and sporty set-up;
  • more limited autonomy and more demanding tires/brakes, even in terms of maintenance;
  • choice for those who want a truly brilliant B-SUV and accept some compromises in terms of practicality and electricity consumption.

If you're considering a Junior, we recommend starting with your actual usage (annual kilometers, type of routes, charging options) and then cross-referencing the technical data with the information on problems, defects, and recalls we've collected in our dedicated article. This way, you can choose not only the most attractive trim, but above all, the most suitable and sustainable technical configuration over time .

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SPARE PARTS AND TECHNICAL SUPPORT FOR ALFA ROMEO JUNIOR

If you have any questions about engine oil, filters, brakes, batteries, or hybrid/electric components for your Alfa Romeo Junior, you can contact us through our shop: we'll help you identify the right spare parts based on your chassis, engine, and year , avoiding compatibility errors that can cause serious problems in the long run.

Go to the Tritella Auto Parts shop →