Currently reading: Alfa Romeo 4C - full technical details
Alfa Romeo 4C uses a mixture of composites and traditional materials in production
Julian Rendell
4 mins read
23 June 2013

The £50,000 Alfa Romeo 4C has been conceived as a supercar-beating sports car whose combination of light weight, modest power and agile handling might be expected to see off heavier, more powerful and pricier exotics.

“We could see a situation where a 
4C driver might easily be quicker on tight, twisting roads, like a mountain pass, than a supercar like the Bugatti Veyron because of its agility and compact size,” says European sales boss Louis-Carl Vignon.

Last week Alfa lifted the lid on some of the technical highlights that might deliver this giant-killing performance, including the first look at its carbonfibre tub, alloy subframes, running gear, composite panels and lightweight glass.

Although the carbonfibre tub makes up just 10 per cent of the 4C’s kerb weight, it accounts for a quarter of the material volume. Aluminium (subframes, suspension and engine block/transmission casing) accounts for 38 per cent of the kerb weight and steel (engine/gears, suspension, rollover protection) 23 per cent. The composite body is seven per cent.

The main figures are a 65kg carbonfibre tub and an 895kg dry weight, which is expected to nudge towards 1100kg as a final ‘in-service’ figure when liquids and a fuel load are added, together with the legally required 75kg driver with luggage.

Alfa Romeo has targeted a weight-to-power ratio of below 4kg/bhp. At the quoted dry weight, Alfa says it has achieved 3.85kg/bhp, sufficient for 0-62mph in 5.0sec. Top speed is 155mph.

Trying to avoid the obvious comparison with the steel-bodied Porsche Cayman/Boxster, Alfa is proud of the 4C’s performance. “We are faster than other similar cars,” says Vignon. “The performance is quite something. This is a real pure-bred Alfa.”

The engineering spec is a long roster of lightweight materials. The sheet moulding compound (SMC) composite used in the body is a special lightweight formulation. Even the glass has been pared down to keep weight low.

Many aspects of the 4C are simple. The steering is unassisted, saving the weight of hydraulics, and the electrical system is relatively simple, featuring fewer than 10 ECUs. The manual air-con, for example, was chosen partly because it doesn’t need an ECU and keeps the engineering lightweight.

Alfa has confirmed that the first UK cars will arrive in late August, with customers of the first, higher-spec Launch Edition models possibly 
taking delivery in September.


Alfa is at pains to point out that the 4C will be powered solely by a four-cylinder engine mated to a dual-clutch automatic gearbox. Rumours persist, however, that a V6 will come eventually. ìThe four-cylinder is perfect because it gives us the performance of a six but is much lighter, says European sales boss Louis-Carl Vignon. Emissions are better, and in many European markets that is becoming more important, even for sports cars, for 
tax reasons.


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Car review
Alfa Romeo 4C
Alfa 4C is built to encapsulate all of the Alfa Romeo brand values

The 4C is Alfa's first true driver's car for decades, and it shows how brilliantly a small turbo four can go and sound in a lightweight package

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The 237bhp, 1.7-litre turbo engine is a lightweight version of the 1750TB engine in the Giulietta, with an alloy block in place of iron, which saves 65kg. Project engineer Domenico Bagnasco says the dual-clutch automatic gearbox 
has been retuned for sharper responses.


The suspension is steel wishbones at the front and alloy struts at the rear. The front suspension is bolted directly to the carbonfibre tub, rather than hung off the front subframe. To ensure dimensional accuracy for the suspension set-up, the mounting faces are machined to an accuracy of microns. The front subframe supports the body and radiator and doubles 
as the crash structure, which crumples to protect the tub from damage. 

Project engineer Domenico Bagnasco says the rear strut design is different from typical practice, with lower mounting points internally for the damper units and lower spring mounts to get the package height down in the low-slung 4C. Struts are also used at the back on the Porsche Boxster and were fitted to the fabled Lancia Delta Integrale.

Carbonfibre tub

The 4C’s carbonfibre chassis will have the highest production volume of any to date, with output planned at a maximum of 16 per day. That’s about 3500 a year. Supplied by Adler Plastics, an Italian carbonfibre specialist based near Naples, it’s the firm’s first road car tub. Adler normally makes racing and aerospace parts and, for Maserati, carbonfibre trim. The tub uses ‘pre-preg’ carbonfibre, which is hand-laid in a one-piece mould and oven cured in vacuum bags. It takes 90 man hours to create. Although this display tub has an all-over polished finish, production cars are polished only where carbonfibre is visible — on the inner sills and central structural backbone.

Body production line

A new building has been converted at Modena to fit out the carbonfibre tub with sub-components and clothe the structure in composite body panels. Panels are painted off-site at a Modena specialist that also sprays Maserati’s special body colours. There are 864 components in each 4C, 136 of them in the main tub/subframe/body structure.

Uniquely, the 4C is the first car to have its body assembled at Modena using composite panels shipped in from a supplier. All previous Maserati models have been assembled from built-up bodies supplied by local coachworks. The GranTurismo, for example, comes in from Turin. To ensure the quality of assembly of the tub, subframes and panels, a digital measuring arm checks 350 points on each completed shell.

Final Assembly

The 4C final assembly line occupies space previously used for the Maserati Quattroporte; production of Maserati’s new four-door has moved to Turin. There are nine main assembly ‘stations’, each manned by between two and three workers, who have 14 minutes to perform multiple assembly operations. The 14-minute ‘cycle time’ is long by volume car factory standards; typically, they are as low as one minute. But 14 minutes has been the standard Maserati cycle time at Modena, so it is also adopted by Alfa. Station 4, where the engine and gearbox are installed, is one of the most time consuming. Overall, it takes between 20 and 25 hours to complete the build, which is spread over about three weeks. By comparison, a Maserati takes about 60 hours over two months.

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Join the debate


23 June 2013

Breathtakingly gorgeous!! ... BUT ... Where does the front number plate go?

Apart from Truvelo speed cameras and DVLA checks, there is NO justification for a front number plate on ANY vehicle ...

24 June 2013

Suzuki QT wrote:

Breathtakingly gorgeous!! ... BUT ... Where does the front number plate go?

Apart from Truvelo speed cameras and DVLA checks, there is NO justification for a front number plate on ANY vehicle ...

Ouch!  Wherever that plate goes its going to look like a right lemon on the front.

23 June 2013

A.  It looks like a squashed up, much uglier version of a Lotus Evora.

B.  Like all Alfas it looks wrong at the front end - nice until you put a registration plate on it then it looks all lopsided with the plate on one side.

Note to Alfa Romeo and Suzuki QT (above): British Construction and Use regulations require  a front number plate to be fitted to all new cars.  Please design your cars accordingly.

23 June 2013

Historically, many Italian cars have had offset front number plates so it's entirely appropriate that 4C is similarly 'endowed' or 'afflicted' depending on how conservative your outlook on life is.

UK front number plates look as if they have been designed by kids i.e. unnecessarily large.  The Truvelo argument is a non argument; after all, grey imports (and foreign registered cars visiting UK) use smaller number plates without creating auto-read problems.

BTW, it's easy to have an Italian size front plate and still be UK legal; just get a 5 or 6 character personalised number and have the plate made the appropriate length.   Contrary to popular belief, there is no spec. for the size of a UK plate; just a spec. for reflective background, character style & size, spacing and borders.   So fewer characters allows for shorter plate.

Anyway, if the front number plate issue is the one that matters most to you above all other cutting-edge attributes, evidently 4c isn't the car for you.   So move on, get something big and heavy and...hmmm...conservative!

23 June 2013

Scotital wrote:


Anyway, if the front number plate issue is the one that matters most to you above all other cutting-edge attributes, evidently 4c isn't the car for you.   So move on, get something big and heavy and...hmmm...conservative!


It's a fair point because all Ferraris, Lamborghinis, Aston Martins, Lotuses, Porsches, BMWs, Jaguars, etc etc etc, are "big and heavy and....hmmm.....conservative", aren't they!!  Doh!!

Just admit it, Alfa Romeo get the front end wrong every time.  They all lack symmetry, and just look wrong.  I'm all for designers trying something innovative, something different, but not if it just ends up looking wrong.

23 June 2013

If this article outlined the production secrets of the latest Porsche or Honda halo vehicle, let alone another half dozen reliable but less interesting manufacturers, I'm sure we would all agree that its sounds exciting, but Alfa?

Sounds like a lot of bespoke engineering that might not have gone through quite enough testing.

Interesting that the tub is produced by the firm responsible for Maserati CF trim.

I'm sure the trim they produce is excellent but not quite the same is it?

I love the idea of this car and very happy they are actually producing it.

I hope it proves to be a step change in the quality of desirable alfas.


23 June 2013

The weight does not have to legally include driver or luggage.



23 June 2013

Perfect size and weight for a sports car, sensual styling that doesn't take itself too seriously, and it just oozes Italian flair.  Especially the cheeky offset plate, like a sexy, slightly lopsided grin on a beautiful woman.  Alfa is back!

23 June 2013

To make a really fast car it needs to be light, have good handling and power.

For some reason most manufacturers seem to add lots of power but the cars are too heavy to make them truely fast. I commend the 4C's focus on weight saving but then why ruin it by giving it only 237bhp?

Personally I'm in the market for something thats light AND powerful, not light OR powerful.

23 June 2013

O my ears!?! Just get a car that matches yours beloved licence plate!

BenS1, may I recommend the Hennesy Venom GT, would just suit your taste. Now put your money where your mouth is.

Looks like a nice car, an interesting engineering effort with some decent quality control, and probably - as remains to be seen, a proper drive. Let's see if that carbon tub will make people pay...


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