The throbbing engine beneath the bonnet of every Alfa Romeo has always determined the model's character more than any other part of the car. The six power units available with the New Alfa 166 all offer different characteristics: they include petrol, turbodiesel and a choice of four, five or six cylinders. Altogether they make up a comprehensive range able to meet the expectations of any customer. However perceptive and demanding. 

Each of these different gems of automotive engineering is outstanding within its own category for technology, performance, reliability and environmental compatibility. First up, the brand new 129 kW (175 bhp) 2.4 JTD 5 cylinder Multijet 20v belongs to the latest generation of Common Rail power units, i.e. multivalve JTD engines with Multijet technology.

Next comes the 110 kW (150 bhp) 2.4 JTD 10v, also an expression of the most sophisticated turbodiesel technology. Due to its revolutionary Unijet injection system, the power unit is silent and offers outstanding performance combined with good fuel economy. Suffice it to say that a New Alfa 166 equipped with this engine can reach a top speed of 210 km/h without any increase in fuel consumption: over a combined cycle, for example, it uses just 7.2 l/100 km. 

The 2.4 JTD 10v unit offers a cylinder capacity of 2387 cc and a 5 cylinder structure with two parallel, vertical valves per cylinder that are operated directly by a single overhead camshaft. It is equipped with a variable geometry turbocharger that succeeds perfectly in adjusting the turbine rotation speed - and hence turbo pressure - by altering the vane angle to speed up or slow down the gas flow rate. The result: the turbocharger is able to ensure maximum adaptability to different engine service conditions by exploiting exhaust gas energy to the full. Together with the intercooler, the turbocharger assures this power unit a high peak power (150 bhp - 110 kW at 4000 rpm), outstanding torque at low speeds (305 Nm at 1800 rpm) and great driving flexibility. As far as the driver is concerned, all this means great driving flexibility.

So much for the turbodiesels. Alfa Romeo is also in the vanguard when it comes to its petrol engines: all offer outstanding levels of power and torque despite miserly fuel consumption. The new model now also offers a powerful 176.5 kW (240 bhp) 3.2 V6 24 valve unit. Tried and tested units from the previous model include the 150 bhp 2.0 TS, the 188 bhp 2.5 V6 24v and the 220 bhp 3.0 V6.

The 2.0 TS 16 valve engine is a showcase for Alfa Romeo's experience with Twin Spark technology. It comes with a variable geometry intake system that fills the cylinders with air optimally to ensure an outstanding response around town and on the motorway. The result is a powerful, flexible engine, as borne out by the high torque (181 Nm at 3800 rpm), 90 percent of which is available even before the engine reaches 2000 rpm. Maximum power is 110 kW (150 bhp) at 6300 rpm. When equipped with this engine, the new Alfa 166 reaches a top speed of 211 km/h and accelerates from 0 to 100 in 9.8 seconds. 

The 2.5 and 3.0 V6 24 valve units, the outcome of cutting edge automotive engineering, offer an outstanding balance of top performance and flexible running. The 2.5 unit offers a cylinder capacity of 2492 cc with maximum power of 138 kW (188 bhp) and 221 Nm of torque. It is a capable of a top speed of 225 km/h and consumes 11.9 l/100 km, again over a combined cycle. The acceleration figures for this engine are also at the top of its category: it can speed from 0 to 100 km/h in just 8.4 seconds.

The New Alfa 166 complements this power unit with a 3.0 unit with a cylinder capacity of 2959 cc. A rating of 162 kW (220 bhp) makes this one of the most powerful in its category. It delivers a peak torque of 265 Nm at 5000 rpm and takes 8.6 seconds to speed from 0 to 100 km. Its speed is also one of the best in its category: 236 km/h.

Both power units feature a six cylinder 60 'V' configuration. The four valve per cylinder head contains a roofed combustion chamber and a central spark plug. The angle between valves is 37 degrees. Throttle opening is controlled by an electronic control unit without any mechanical connection between accelerator pedal and throttle body. Electronic engine management is assured by a Bosch Motronic ME 2.1 system. 

The electronic throttle also assures fast catalytic converter activation when the engine is cold (the throttle opening is wider than requested by the accelerator) for improved emission control. Other engineering features adopted on the 2.5 and 3.0 V6 24 valve unit include: 

- a no-return fuel feed system; 
- a lubrication system that directs oil jets on the piston crown; 
- an air-oil heat exchanger that heats up the oil and engine more rapidly after cold starts; 
- static ignition with one coil per cylinder with dual knock control. The 3.0 V6 24 valve power unit is available only with automatic transmission. This takes the form of a 27 kgm torque Sportronic unit that adapts automatically to the driver's driving style and the type of route. It chooses the most effective gearshift strategies itself on the basis of these two parameters. 

Now we will take a detailed look at the two new engines available on the Alfa Romeo flagship - and the brand new Aisin automatic transmission.

The 129kW (175bhp) 2.4JTD Multijet 20v

We now welcome the powerful 5-cylinder 129 kW (175 bhp) 2.4 JTD Multijet 20v, the second engine in the JTD multivalve family with Multijet technology.

This brand-new unit offers various benefits. The engine is quieter as it warms up. The improvement can be quantified as a reduction of 3 to 6 decibels depending on engine speed and environmental temperature. Then, great power (175 bhp - 129 kW at 4000 rpm + 25 bhp compared to the 2.4 JTD 10 valve) and generous torque (385 Nm - 39.3 kgm at 2000 rpm against the 305 Nm at 1800 rpm of the 2.4 JTD 10v). The new unit also reduces emissions even though it is not fitted with sophisticated exhaust gas treatment devices. 

The new engine is derived from the tried and tested 2.4 JTD 10 valve Common Rail unit and takes the form of a five cylinder in line unit with bore of 82 millimetres and stroke of 90.4 millimetres. The four valves per cylinder are driven directly by a twin overhead camshaft via hydraulic tappets and rocker arms. The new turbodiesel has undergone several engineering changes to increase performance and engine torque at low speeds and to reduce noise levels and vibration.

For example, the Common Rail system used on the 20 valve 2.4 JTD Multijet unit includes two new strategies for automatically calibrating and balancing the diesel injected to lower noise and reduce vibration. Certain engine components are brand new: a cylinder head with hydraulic tappets, steel connecting rods and crankshaft, a piston with an internal channel to carry cooling oil to the main and connecting rod bearings that are made out of different material to the previous unit. The exhaust and intake manifolds are also new: the former is made out of a special high-strength material while the latter is made out of pressure cast aluminium. 

The electronically-controlled EGR system is cooled by exhaust gas. The lubrication circuit has a new oil pump and an external heat exhanger (air/oil) for cooling the oil. The cooling system is fitted with a different water pump. This long series of improvements and changes has created a reliable, powerful engine with low fuel consumption.

These results have been achieved by adopting a new engine setting, increasing the direct injection pressure from 1350 to 1400 bars and introducing a new turbocharger setting. 

The power units are turbocharged via a Garrett turbocharger with variable geometry turbine that helps improve power delivery by allowing very high torque delivery even at low rpms. Suffice it to say that 90% of peak torque is available between 1750 and 3500 rpm. These data translate into great driving satisfaction and truly inspiring performance. The new Alfa 166 reaches 222 km/h and accelerates from 0 to 100 km/h in 8.9 seconds. All this comes with very frugal fuel consumption: 7.5 l/100 km over a combined cycle, 9.9 over an urban cycle and 6.1 over an extraurban cycle. These outstanding results are achieved by pairing the 2.4 JTD Multijet 20v with a new 6-speed manual gearbox. The 3-axle device is more compact than the present one and presents synchronised reverse and a clutch with automatic wear take-up.
When fitted with an Aisin automatic transmission, the car returns a top speed of 218 km/h and acceleration of 8.9 seconds. Fuel consumption figures are 12.1 l/100 km over an urban cycle, 6.9 over an extraurban cycle and 8.9 over a combined cycle.

The Multijet System

The underlying principles of second generation turbodiesel engines remain the same, i.e. high injection pressure and electronic injector control. With one extra feature: during each engine cycle, the number of injections increases over and above the current number of two. In this way, the same amount of diesel is burnt inside the cylinder but in several portions to achieve smoother combustion. 

The advantages include quieter running, a reduction in emissions and an increase of about 6-7% in performance, accompanied by a drive efficiency that improves driveability even further. These results are not to be underestimated, remembering that they are obtained with an engine that represents an incredible leap forward from prechamber diesels and even improves on first generation JTD engines. 

The secret of the Multijet engine lies in the control unit that governs the electric injector opening and closing system (and also in the injectors themselves). The crucial element is indeed this very electronic control unit that can perform a set of injections that may be very closely spaced. 

Fiat Auto's researchers developed the part (together with the injectors) especially for this application. It is designed to deliver the multiple injections that assure the designer more accurate control of pressures and temperatures developed inside the combustion chamber and also more efficient use of air taken into the cylinders.

This enables further goals to be achieved: quieter combustion reduced emissions and increased performance.

The Multijet system is underpinned by long years of research. Our engineers began by resolving the problem of limits imposed by the control units. Then they went on to map the benefits they could achieve by plotting different multiple injection sequences (two secondary injections very close to the main injection; one secondary injection not too close to the main injection plus two closely-spaced secondary injections; one secondary injection and then two main injections close together after a certain period etc.) against different engine service conditions: in the idling region; with low loads and low rpm; with high rpm and moderate load; with low rpm and high load etc. 

The study revealed the potential of the system and showed that great benefits are achievable in all cases, though these tend to focus on one field or another according to the type of sequence chosen and the engine service area targeted. In some cases, for example, the priority is to reduce start-up times and fume levels, in other cases it is to increase torque and reduce noise while in others it is to reduce emissions and ensure a quieter drive.

And now this research strand has led to the creation of Multijet engines: another first for the Fiat Group in the diesel engine field. All this was possible because we have been building up know-how in this field since 1986, the date that marked the arrival of the Croma TDI, the first direct injection diesel vehicle in the world. 

At that time, this represented a true engineering breakthrough that was later adopted by other manufacturers. Direct diesel injection engines offered better performance and lower fuel consumption but failed to resolve the problem of excessive engine noise at low rpms and while speeding up or slowing down. So work began on a more advanced direct injection system and a few years later this led to the development of the Common Rail principle and the Unijet system. 

The idea first came from the Zurich University research laboratories where scientists were working on an injection system that had never before been applied to a vehicle, i.e. the Common Rail system. The idea is simple yet revolutionary. If you continue to push diesel into a tank, the pressure inside will rise and the tank itself will become a hydraulic accumulator (or rail), i.e. a reserve of pressurised fuel ready for use.

Three years later, in 1990, the Unijet system developed by Magneti Marelli, Fiat Research Centre and Elasis on the Common Rail principle entered the pre-production stage. This stage was complete in 1994, when Fiat Auto started to look for a partner with superlative knowledge of diesel engine injection systems. The final stage of the project, i.e. completion of development and industrial production, was eventually entrusted to Robert Bosch.

Now our story has reached 1997 and the launch date of the Alfa 156 JTD with its revolutionary turbodiesel engine. Compared to conventional diesel power units, the JTD guarantees an average improvement in performance of 12% together with a 15% reduction in fuel consumption. These results meant that cars fitted with the engine were an immediate hit. 

Now the time is ripe for the second generation of JTD engines, the Multijet and multivalve units: in 2002 with the 1.9 JTD Multijet 16v (the forerunner of this new multiple injection family), today with the 129 kW (175 bhp) 2.4 JTD Multijet 20v.

3.2 V6 24v

The New Alfa 166 now offers a scorching 3.2 V6 24v. The 3.2 litre unit, derived from the 3.0 V6 24v that is fitted to the current flagship version, adapts perfectly to the new model to create a great luxury saloon with a uniform standard of roominess, comfort and performance. 

This power unit is vigorous and, above all, turns as roundly as a six cylinder engine should. It is remarkable for its power output and flexibility. This unit unleashes a power output of 240 bhp (176.5 kW) at 6200 rpm with a maximum torque of no less than 289 Nm at 4800 rpm. All you need to achieve remarkable performance on demand, with a torque curve that reaches high levels at low speed. 

The thing that makes the most difference is the painstaking work that our engineers put in to ensure that this power unit delivers the type of performance you expect from an Alfa Romeo. This refinement has been achieved through a myriad of tiny changes to obtain extremely smooth, gradual power delivery without jerkiness during application or release. All this makes for a much smoother drive.

Several parts have been revised to achieve this result: from the accelerator control to the injection and ignition times. One reason is to ensure that the increase in performance is never to the detriment of fuel consumption, because this is bound to respect ever more stringent rules.

Altogether, the New Alfa 166 3.2 V6 offers an outstandingly satisfying drive. Its top speed is 245 km/h; it takes 7.4 seconds to speed from 0 to 100 km/h. Over an urban cycle, it consumes 18.3 l/100 km, 9.1 over an extraurban cycle and 12.5 over a combined cycle. 

When equipped with this power unit, the Alfa Romeo is the ideal car for customers who seek great performance but delivered with absolute smoothness. For people who do not like to be second to anyone, even on the road. For people capable of falling in love with a car for its good looks and luxury and for the unmistakable throb of its engine.

In detail, the 3.2 V6 24v features 6 cylinders in a 60° V with aluminium crankcase and cylinder head. The combustion chambers are roofed with a central spark plug while the valves are positioned at a tight angle (37°). 

The engineers changed the crankshaft and pistons to increase the cylinder capacity to 3179 cc and lengthened the stroke to 78 millimetres. This change speaks volumes about the type of performance required because the power could simply have been increased by adjusting the timing, fuel system and electronics. The fact that cylinder capacity has been increased by lengthening the stroke means that the aim was not simply to obtain out-and-out performance coupled with high power and torque peaks but also an even, gradual power delivery from the lowest speeds. As befits a car capable of thrilling performance that is suited for driving on ordinary roads as well as on the track. 

The increase in cylinder capacity is naturally accompanied by a whole set of changes. The intake ducts have been tuned, with a new valve gear timing setting. The injection system is also new. It takes the form of a Multipoint system with sequential injection, Bosch Motronic ME7 electronic management and no-return system with selective knock control.

The accelerator is drive by wire, i.e. with no mechanical links between the accelerator pedal and throttle. The throttle is electrically controlled by the engine management control unit. This solution brings benefits in terms of fuel consumption and emissions and also when it comes to driving satisfaction. 

During cold starts, for example, the system reduces the warm-up period by activating the catalytic converter more quickly but does not impair torque and thus car handling during the first few minutes. Acceleration stages are also more effectively managed because the control unit can obtain information on the driver's requirements before imparting the command to the throttle. Speed can also be governed electronically by means of the Cruise Control system.

The 3.2 V6 24v is also fitted with a water-oil heat exchanger instead of an air-oil exchanger to heat the engine oil more quickly after cold starts.

Other attributes of this power unit include its low maintenance requirements. Suffice it to say that, apart from oil changes, the first service does not fall due for 100,000 km. This is due to certain engineering features such as spark plugs with twin platinum electrodes, hydraulic tappets and automatic tensioners for the timing belt and poly-v belt.

The 3.2 V6 24v engine is a lively performer and also clean. It comes with two trivalent preconverters built into the stainless steel exhaust pipe and a double converter beneath the floorplan complemented by four heated lambda sensors. The fuel system is no-return, i.e. the fuel does not return to the tank and it comes with a pressure regulation valve built into the fuel pump. This therefore helps to reduce evaporated fuel emissions.

Other important engineering features include: the piston crown oil jet lubrication system; static ignition with one coil per cylinder with dual knock control and a sensor for each engine block in the crankcase - and an effective oil pump driven by the crankshaft.