FACTfile - The new Alfa Brera - Page 4

Engines and transmission

The new Alfa Brera goes on sale in Australia with a choice of two powerplants, two spirited JTS direct injection petrol engines – a 2.2 litre, 136 kW four cylinder unit, and a new, 191 kW 3.2 litre JTS V6.

They combine JTS (Jet Thrust Stoichiometric) direct injection technology with Alfa’s ‘Twin Phaser’ continuously variable valve timing operating on both intake and exhaust camshafts. With specific power outputs in excess of 62 kW/litre, and almost 90 per cent of maximum torque available at just 2000 rpm, both these new JTS units boast outstanding performance yet offer significant fuel savings and readily comply with the stringent Euro Stage 4 exhaust emission limits.

The 2.2 JTS version of the new Alfa Brera is mated to an M32.6 6-speed manual gearbox, whilst 3.2 JTS model is equipped with the F40 6-speed manual transmission. The ratios of both transmissions have been chosen to emphasize performance, and gear change smoothness and accuracy has been enhanced by the use of multiple cone synchronizers.

3.2 JTS versions of the new Brera are fitted, as standard, with Alfa Romeo’s Q4 permanent four-wheel drive system.

3.2 JTS V6

1. 3195cc
2. 60 degree V, 6-cylinders, 24 valves
3. Power: 191 kW @ 6300rpm
4. Torque: 322 Nm @ 4500rpm
5. Timing gear: 4 OHC, continuous dual VVT
6. Transmission: 6-speed manual, 4-wheel drive
7. Top speed: 240 kmh
8. Acceleration 0-100 kmh: 6.8 seconds
9. Fuel consumption:
10. in town: 16.9 l/100 km
11. out of town: 8.5 l/100 km
12. combined: 11.5 l/100 km
13. CO2: 273 g/km

Having made its debut in the new Alfa 159, the spirited new quadruple overhead camshaft all-aluminium 24-valve V6 powerplant features both the company’s JTS direct petrol 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 all-alloy 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.

The 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 previous 3.2 litre unit.

This outstanding new 3195 cc engine 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, via an electronically activated 72 mm throttle valve and an aluminium inlet port casing designed to both maximise air delivery and optimise the air/fuel mixture, the 3.2 JTS engine in the new Brera operates with a lean burn system up to about 1500 rpm, making significant fuel savings. Above this engine speed, however, it burns a stoichiometric fuel-air 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 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 feature ‘Twin Phaser’ continuously variable valve timing – for both intake and exhaust camshafts – 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 a maintenance-free chain drive with automatic hydraulic tensioners, whilst the valves themselves – 33.4 mm inlet and 28.4 mm exhaust diameter – are controlled by a low friction roller finger system with automatic uptake of hydraulic tappet play.

The new Alfa Romeo 3.2 litre JTS V6 combines power and torque peaks of 191 kW at 6300 rpm and 322 Nm at 4500 rpm respectively, with smooth, linear power delivery from low speeds. Some 90% of peak torque is available from just 1800 rpm and maintained up to 6250 rpm. Hence, the 3.2 litre V6 24v unit delivers sensational performance, but is also very docile, and the Brera can cruise effortlessly in sixth gear at less than 2000 rpm, yet accelerate rapidly and smoothly away without the need for changing gear.

Mated to an F40 6-speed manual transmission and Alfa Romeo’s Q4 permanent four-wheel drive system, the 3.2 litre JTS V6 engine will accelerate the new Alfa Brera from 0-100 kmh in 6.8 seconds and on to a top speed of 240 kph.

The V6 exhaust system features a first group of catalysing elements mounted close to the cylinder heads, ensuring optimum operational temperature is achieved as soon as possible after engine start-up. Two underfloor catalysts and four lambda sensors complete the system, which easily meets stringent Euro Stage 4 exhaust emission limits.

2.2 JTS

1. 2198cc
2. 4-cylinders, 16 valves
3. Power: 136 kW @ 6500rpm
4. Torque: 230 Nm @ 4500rpm
5. Timing gear: DOHC, continuous dual VVT
6. Transmission: 6-speed manual
7. Top speed: 222 kmh
8. Acceleration 0-100 kmh: 8.8 seconds
9. Fuel consumption:
10. in town: 13.0 l/100 km
11. out of town: 7.3 l/100 km
12. combined: 9.4 l/100 km
13. CO2: 221 g/km

The all-aluminium 2.2 litre Alfa Romeo 4-cylinder JTS powerplant offers a weight reduction of some 20% over the unit it replaces.

The 16v 2198 cc powerplant also uses ‘Twin Phaser’ continuously variable valve timing, as previously described, with large, 35.3 mm (inlet) and 30.3 mm (exhaust) diameter valves. In addition, it features a maintenance-free chain drive to the twin counter-rotating balance shafts, water pump and low friction camshaft drive system, and is further equipped with a dual detonation sensor to improve sensitivity to engine knock, enhancing maximum performance.

Mated to an M32.6 6-speed manual transmission, the Euro 4-compliant 2.2 litre unit develops 136 kW at 6500 rpm, and 230 Nm of torque at 4500 rpm – this high power output requiring the use of sodium cooled exhaust valves. The Brera 2.2 JTS will accelerate from 0-100 kmh in just 8.6 seconds, and still offer a fuel consumption of just 7.3 l/100 km or better than 30 mpg in the old money.

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