Alfa Romeo’s V6 engines have long been coveted for everything from their performance to their melodic sound, through to even their good looks, so the arrival of a new Alfa Romeo V6 engine is a highly anticipated event. This week (24 July 2006) is, therefore, the week that motoring enthusiasts in Australia and New Zealand have been waiting for with Alfa Romeo’s all-new 3.2 litre V6 arriving in not one, but two new models – the Alfa Romeo 159, and the staggeringly beautiful Alfa Romeo Brera, with two more, the 159 Sportwagon and the Alfa Romeo Spider on the horizon. And, as if that was not sufficient incentive, all come as standard matched to Alfa Romeo’s new Q4 all wheel drive system.

“This new engine has a remarkable heritage,” explains Lawrie Malatios, General Manager for Alfa Romeo in New Zealand. “The previous V6 engine was designed specifically to be a performance engine, endowing all the cars in which it was used with effortless performance, accompanied by an engine howl that can only be described as operatic and even to look at, it was a visual feast. The new engine has to offer all this and add 21st century requirements of fuel economy, low emissions and quick and easy servicing. This it does, providing the Alfa Romeo 159, the Sportwagon, the Brera and, when it arrives later in the year, the new Alfa Romeo Spider, with a wonderful breadth of performance and ability. The fact that it is matched to a new four wheel drive system is just the cream on the cake!”

This spirited new quadruple overhead camshaft all-aluminium V6 powerplant features both Alfa Romeo’s JTS direct petrol injection system and its twin phase continuously variable valve timing. Developed by Fiat Powertrain Technologies, a new industrial enterprise created to integrate all the Fiat Group’s innovation capabilities and expertise in engines and transmissions, the new all-alloy engines feature cylinder heads, pistons, induction and exhaust systems designed and built by Alfa Romeo. Final assembly of this engine is carried out in Italy, at the Pomigliano D’Arco Alfa Romeo plant.
 

This outstanding unit takes its name – Jet Thrust Stoichiometric – from its specific combustion system, an original Alfa Romeo concept that involves the high pressure injection of fuel, at 120 bar, directly into the combustion chamber with a stoichiometric mixture optimised to increase engine power and torque first and foremost – thus adapting this technology to the requirements of a sporting car – whilst adopting the stratified charge method to reduce fuel consumption in a limited speed band close to idling. Hence the 3.2 JTS engine operates with a lean burn system up to about 1500rpm, making significant fuel savings.

Above this engine speed, however, it burns a stoichiometric air-fuel mixture – i.e. with a conventional 14.7:1 ratio between the two components – thus guaranteeing performance superior to that achievable by a conventional, indirect injection unit. Primarily, this is because fuel injected directly into the combustion chamber – instead of the intake ports – cools intake air, thus increasing the engine’s volumetric efficiency. As the temperature drops, so the gases increase in density and the volume therefore decreases, allowing more air into the combustion chamber. Cooling the chamber also reduces the risk of engine knock, allowing for an increase in compression ratio – in this case to 11.25:1 – and a commensurate improvement in engine efficiency.

Allied to JTS technology, the light aluminium alloy cylinder heads of the new 3.2 litre V6 also features ‘Twin Phaser’ continuously variable valve timing – for both intake and exhaust – already adopted on 4-cylinder JTS Alfa Romeo engines. Via two camshafts per cylinder bank, variable valve timing allows the phase angle of both inlet and exhaust cams to be varied by up to 50 degrees, optimising the volumetric efficiency of the engine at all engine speeds whilst reducing fuel consumption and emissions under lighter throttle settings.

The new camshaft drive system features maintenance-free chain drive with automatic hydraulic tensioners, whilst the valves themselves are controlled by a low friction roller finger system with hydraulic uptake of tappet play. This refined new Alfa Romeo V6 arrangement engine combines power and torque peaks of 191 kW at 6200rpm and 322 Nm at 4500rpm respectively with smooth, linear power delivery from low speeds. Some 90% of peak torque is available from just 1800rpm and maintained up to 6250rpm. Hence, the 3.2 litre V6 24v unit delivers sensational performance, but is also very docile, and Alfas fitted with the new engine can cruise effortlessly in sixth gear at less than 2000rpm, yet accelerate rapidly and smoothly away without the need for changing gear.

All versions equipped with the V6 engine will be available in early 2007 with the option of the Alfa Romeo Q-Tronic six speed automatic gearbox.