The Alfa Romeo 159 Sportwagon: Engines And Transmissions
Published: 6th June 2006
The spirited, 3.2 litre four overhead camshaft all-aluminium engine is an all-new powerplant which made its debut in the Alfa 159, and is now installed in the Alfa 159 Sportwagon and Brera ranges. This 60 degree V6 unit features both the company’s JTS direct injection system and 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 chain-driven all-alloy 24-valve engine features 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 in the new Alfa 159 Sportwagon operates with a lean burn system up to about 1500 rpm, 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 now also feature ‘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 powerplant 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 superbly refined new V6 combines power and torque peaks of 260bhp at 6300rpm and 237lb ft 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 the Alfa 159 Sportwagon can cruise effortlessly in sixth gear at less than 2000 rpm, yet accelerate rapidly and smoothly away without the need for changing gear.
JTS direct fuel injection and ‘Twin Phaser’ continuously variable valve timing combine to generate an 8% increase in power and an 11% increase in torque over the superseded 3.2 litre Alfa Romeo V6.
Mated to an F40 6-speed manual transmission and the Q4 four-wheel drive system, the 3.2 litre JTS V6 engine will accelerate the new Alfa 159 Sportwagon from 0-62mph in 7.2 seconds and on to a top speed of 147mph, yet easily meets the stringent Euro Stage 4 exhaust emission limits.
Alfa Romeo 159 Sportwagon
Our Alfa Romeo 159 Sportwagon Guide lists the full specification of the current UK 159 Sportwagon range, including car prices, fuel consumption, dimensions and other vital data.
Price Range: £20,045 - £30,990
Body Style:
Fuel:
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Models in the range: 16
Our Car Buyer’s Guide covers all of the UK’s major new cars and includes CO2 ratings and car insurance groups. Data updated on the 28th Nov 2008
