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.
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.