The Giulietta Quadrifoglio Verde feels at home on country roads...

As we announced already in our editorial, we drove to the Paris Salon at the wheel of a very inspiring Italian thoroughbred, the most powerful version of Alfa Romeo’s new gem, the Giulietta. What an entertaining car it is, this Quadrifoglio Verde. Wonderfully powerful and at the same time so civilised and docile in everyday use…a car with character and many personalities, of which you never tire…

Hans Knol ten Bensel

A wonderful heart

Of course the engine is the heart of every car, and this is certainly so for an Alfa, and especially this one.

...and in Paris city trafic, when we drove it first to our Paris apartment, en route to the Salon de Paris...

Miraculous what modern, state-of-the-art petrol engines are capable of nowadays. It is a 1750 cc four cylinder unit, its “cylindrée” being of legendary proportions for an “Alfista” with a sense for history. But this is where all historical comparison ends. As Alfa puts it, the engine is even more powerful than a “normal” 3 litre unit. It is indeed a superlative machine. On first acquaintance, driving it quietly, it proved immensely docile, silent, vibrationless, and in tune with the times, very frugal. On our “autoroutes” trip to Paris , cruising gently along while getting more familiar with the car, we consumed around 6 to 7 litres per 100 km, at most, with the DNA selector set at “Normal ”.

Then we selected “Dynamic”at the exit of the “péage” close to Paris and pushed the throttle a bit deeper. Wow. Under a deep growl, Giulietta catapulted herself forward with uncanny vehemence, like a temperamentful diva. We were forcefully remembered of the factory acceleration data: indeed, 0 to 100 is absolved in merely 6,8 seconds. More impressive is even the pulling power at low revs. The specific torque, totalling 195 Nm/litre, is the highest of all petrol engines in this category, with a maximum torque of 340 Nm (with the DNA selector set to Dynamic), reached at merely 1,900 revs. It should also be mentioned that also the specific power of 134 HP/litre is the highest ever achieved by an Alfa Romeo engine. When you would totally loose the reins of this Diva, Giulietta could storm swiftly to a top speed of 242 kilometres…  

Optically, there is not much to be seen from this beautiful engine, as it is tucked away under a neat and tasteful plastic cover… but what a divine heart it is. Needless to say that Alfa Romeo sets a benchmark with this engine. We explain it more in detail here.  

State of the art technology.

To achieve such results, the 1750 Turbo petrol engine boasts advanced technical solutions including direct fuel injection, two continuously variable valve timing units, a turbocharger and a revolutionary scavenging control system that puts any turbo lag definitely to the history books. Let’s take a closer look:

Well dosed scavenging technology

Effective scavenging is achieved by monitoring and optimising, instant by instant, the engine operating parameters of fuel dosage, the position of the two phase transformers, the ignition advance and the injection timing. In practice, the new valve timing system defines valve overlap angles and times with extreme precision, generating a direct air flow from the intake manifold to the exhaust manifold and activating the turbocharger instantly. This new system therefore makes far better use of the turbocharger than conventional turbo petrol engines. It is controlled by an innovative ECU installed with ultra-modern engine parameter management software. In this way, the maximum torque at 1,500 rpm is 70% greater than that of a conventional turbo engine and response times have been more than halved, closely approaching those of a naturally aspirated engine.

Direct injection for cool and clean power

Direct injection reduces temperatures in the combustion chamber through fuel evaporation, dramatically reducing the likelihood of detonation. This allows superior performance to be achieved even at quite high compression ratios (around 9.5) and guarantees low fuel consumption at partial throttle settings.

Direct injection is essential for reducing emissions through an advanced dual-injection strategy. Precise control over the moment the fuel is injected also ensures that no fuel arrives directly at the exhaust valve during the scavenging phase, which would compromise the functioning of the catalytic converter. Finally, the second-generation injection system features a new, high-pressure pump (capable of managing fuel pressures of 150 bar) and innovative seven-hole injectors which guarantee ideal atomisation of the fuel under all engine operating conditions.

Dual variable valve timing

The two continuous variable valve timing units on the intake and exhaust camshafts optimise valve timing at all engine speeds and loads.

The two valve timing units are linked to the turbocharger, which enables to manage the scavenging process by choosing the ideal valve opening and closing overlap. When the driver requests a sudden increase in torque, the system responds instantly, even at very low revs.

Latest generation “hot” turbo…

The so-called “next-generation” turbocharger connected to an innovative “pulse converter” exhaust manifold which uses the exhaust pressure waves optimally to increase torque at low engine speeds. Both the manifold and the turbine are made of microcast steel to withstand the very high operating temperatures (up to 1020°C) needed to reduce fuel consumption while driving at medium/high speeds on motorways.

Thermal fluid dynamics

The intake ports are designed and optimised by using mono- and three-dimensional computing technologies. This makes it possible to reach the level of turbulence needed to obtain high combustion efficiency, and to create both an optimal mixture of air and petrol and rapid combustion with reduced cyclical dispersion even at low revs.

The Giulietta bears the Quadrifoglio emblem proudly...

The design of the combustion chamber has also been optimised by extending the squish areas and minimising the ratio of surface area to volume, to the benefit of combustion. Finally, the exhaust ports have been designed to work together with the exhaust manifold in order to maximise its pulse converter effect…. State of the art!

Reduced friction

The entire engine has been designed to minimise power losses through friction. The pistons feature rings with low tangential load and are made of advanced, low wear materials. The cylinder head incorporates roller rocker arms that have reduced sliding contact losses at 2,000 rpm by 65% compared with the old Twin Spark cylinder heads. Optimised crank shaft design based on a very long connecting rod and a comparatively short piston stroke has minimised the vibrations normally associated with four-cylinder engines at high speed. In this way balancer jackshafts were not needed, further improving engine efficiency.

A wonderful chassis

The Alfa convinces not only with its engine, also the gearbox, seating position, interior styling and finish is what we expect from an Italian thoroughbred with character. All the controls are easy and intuitive to use, and the Alfa is truly a delight to drive in everyday traffic. We let you enjoy the photographs which evoke the spirit and “presence” of the car. On the Paris show we also came eye to eye with the chassis display of the Giulietta, and were impressed to say the least.

Again we explain this more in detail:  

Superb brakes

The Giulietta Quadrifoglio Verde is fitted with 330 mm self-ventilating front brake discs and aluminium Brembo fixed brake callipers with 40 mm diameter piston; the rear wheels are fitted with solid brake discs (278 mm in diameter) and the brake callipers are made of cast iron with a 38 mm diameter piston. Quite frankly, they are eminently up to the task…

The ABS system is incorporated with EDB (Electronic Brake force Distribution). The latter distributes the braking action over four wheels, in order to stop the wheels locking and ensuring complete vehicle control in all conditions. Moreover, the system adapts its operation to wheel grip conditions and to brake pad efficiency, while also reducing the overheating of the latter. State of the art…

And VDC (Vehicle Dynamic Control) to help the Alfa pilot…

VDC is Alfa Romeo's interpretation of ESP (Electronic Stability Program), a system that intervenes in conditions approaching the limit, when vehicle stability is at risk, and assists the driver in controlling the car. A sporty device, in the spirit of all true Alfa Romeo cars, featuring excellent road holding qualities, the VDC system gives the driver total freedom to master the vehicle in normal conditions and only intervenes immediately prior to the situation becoming critical. The VDC, by the way, is always in operation.

Dashboard controls are clear and intuitive to use...

When there is a brisk gear change in poor grip conditions, the MSR (Motor Schleppmoment Regelung) function intervenes,  restoring engine torque and preventing the wheels from locking and slipping. To achieve this result, the VDC continuously checks tyre grip, in both longitudinal and lateral directions, and it restores directionality and ride stability in the event of a skid. Thanks to sensors, it detects the rotation of the car body around its vertical axis (yaw speed), the lateral acceleration of the car and the angle of the steering wheel set by the driver (which indicates the chosen direction). The device then compares this information with the parameters processed by an ECU and it sets out - by means of a highly complex mathematical model - whether the vehicle is driving round a bend within the limits of its grip or if it is about to veer to under- or oversteer.

To return the vehicle to the correct trajectory, it generates a yaw moment contrary to the one which caused the initial instability, braking the relevant wheels individually (internal or external) and reducing engine power (acting on the throttle).

This is where the peculiarity of the device made by Alfa Romeo's engineers lies. Its effect on the brakes is modulated to be as gentle as possible (therefore without disrupting driving) and the engine power reduction is contained, to guarantee sporty performance levels and maximum driving satisfaction at all times.

To top it all: Alfa DNA and the new Pre-Fill function

The Giulietta is fitted with the Alfa DNA system, an innovative system which controls the main driving parameters (engine response, stability control and steering assistance). Until recently available only for racing cars or supercars, the Alfa DNA system acts on the engine, brakes, steering, suspension and gearbox, allowing three different vehicle behaviour modes, depending on the most suitable driving style for the conditions or the desires of the driver: sporty (Dynamic), urban (Normal), and maximum safety even in low grip conditions (All Weather).

The DNA inscription lights up on the dashboard...

The selector is well located  – in front of the gear lever on the tunnel – and allows the driver to select one of three operating modes, simply by moving the lever (the selection is displayed by a specific LED switching on together with a message on the instrument panel display).

In detail, if you want relaxed, safe driving, you choose the Normal mode, and each individual component affected by the Alfa DNA system is then in its “normal” configuration: lively engine, highly discreet Vehicle Dynamic Control and a DST (Dynamic Steering Torque) which sees that oversteer is avoided.

If you are more inspired, you move the lever to the Dynamic setting: in this mode, DNA enhances your driving experience, thanks to the fact that the system makes the VDC and ASR less intrusive (so the vehicle dynamic control is a little more detached from the electronic control) and concurrently enables the Electronic Q2 system. Moreover, again in Dynamic mode, the Alfa DNA also acts on the steering and engine to offer a truly complete and enjoyable sporty experience. The steering is less power assisted and gives the driver a more sporty feel, guaranteeing perfect control.

The Giulietta is also introducing Pre-Fill - a new function (activated when the DNA is set to Dynamic) which uses the VDC system to provide the driver with the quickest braking response possible. In detail, the control unit recognises the driver's desire to brake from the speed at which accelerator pedal is released. At this point the VDC increases the pressure inside the braking system by several bars to take up any play and create the sensation of quicker braking response and reduce braking time.  

The third mode enhances the traction control effect and enhances response to mu-spit (the DST function - active electronic steering) which intervenes when driving on surfaces with different grip (for instance, it is often the case in winter when two wheels are on ice while the other two are on the tarmac).

When the selector is set to All Weather, the Alfa DNA system makes the car easier to control even on low grip surfaces (on wet or snowy surfaces, for instance), acting on the vehicle dynamic control, lowering the VDC intervention threshold.

Enough said? We would think so, but we wanted to describe to you in detail the wonderful engineering solutions which went into this Alfa. Needless to say we regretted parting with the car, as we are also in finishing this test report, because a thousand words can not describe how wonderful it is to be with Giulietta (see photo below...) on whichever path or road life takes you…

Hans Knol ten Bensel