Currently reading: Alfa Romeo 4C - full technical details
Alfa Romeo 4C uses a mixture of composites and traditional materials in production
Julian Rendell
News
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.

Engine


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.

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.

Advertisement
Advertisement

Find an Autocar review

Read our review

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

Back to top

Suspension

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.

Back to top

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.

Join the debate

Comments
24
Add a comment…
lfsv8 26 June 2013

ALFA 4C

The next Alfa Romeo I buy will be the first.  Such is for no reason other than the [apparent] lack of dealer support & potential for unreliability of the past.  However, if Lotus & TVR are anything to go by, having owned examples of both and found them not-at-all troublesome, perhaps Alfa's build quality/unreliability reputation is similarly more 'media shorthand' and/or deliberately the product of any "opposition's" anti-campaign (i.e. wholly commercial in reality), than anything else?

If those chosing to adversely criticise the 4C, can only do so based upon front number plate sizing & position or 'pominence' of the front badge, that's rather telling/somewhat marginal at best.  As an inveterate sportscar fan, the 4C seems to be an almost-affordable 'dream come true'.  Alfas seem to epitomise TVR's former label of "The Spirit of Driving" and this aged & respected marque has perenially shown great imagination & wonderful performance.  What's more the 4C's production engineering techniques based at the Maserati works appear to significantly rival the 'hi-tech' methodology of Hethel.

So, the main problem with the 4C probably becomes: how to save up quickly enough/at all when most UK citizens have had 'austerity' heaped upon them via the continuing need to defray the costs incurred by the unethical excesses of the [incompetent] Financial Engineers & Politicians - groups patently lacking in adequacy of their collective imagination, if you like: "folks who know the price of everything but the value of very little" and have their vision obfuscated by sheer greed, perhaps?

Oh dear!  But, very well done indeed Alfa - there's hope for us all yet due to your sort of imagination and patently practical design & engineering skills!!

martin_66 27 June 2013

lfsv8

lfsv8 wrote:

If those chosing to adversely criticise the 4C, can only do so based upon front number plate sizing & position or 'pominence' of the front badge, that's rather telling/somewhat marginal at best.

I actually think this car looks really nice at the rear end, and fantastic at the front end, despite my criticisms.  HOWEVER - put this on the road and it will require a front number plate, at which point, like all Alfas, it will look lopsided, and undo all the designers' good work.

The side profile looks too much like a Lotus Evora as well.

Just out of interest, what is "rather telling" about wanting a car not to look odd?

Cyborg 24 June 2013

Lights

Those production model headlights are very ugly! Why do they use them? They're not a shadow of the concept-car version, which didn't seem that far out. Anyway they need to go - maybe with the facelift in a few years.

They really spoil the styling in my opinion.

Dazed and Confused 24 June 2013

I love the off-set numberplate

 

I think people have become incredibly conservative in terms of car design. This obsession with symmetry and homogeneity is all rather sad. Cars are symmetrical because it's easier for packaging and regionalisation - nothing to do with beauty.

I am glad that there are companies like Alfa who do things differently.  But if you don't like it it doesn't mean it's 'wrong'. 

And personally I think asymmetry can be beautiful, and the off-set plate in this case is a lovely finishing touch.

Find an Autocar car review