The new 250 hp (184 kw) 2.8-liter V-6 Turbo engine in the Saab 9-3 Aero Sport Sedan, SportCombi and Convertible represents the culmination of almost 30 years' experience from Saab as acknowledged leaders in the art of turbocharging. The 9-3 Sport Sedan Aero with its new V-6 Turbo is, quite simply, the fastest accelerating car ever to carry the Saab badge.

In the new 9-3 Aero, Saab customers are now able to enjoy the combined benefits of turbocharged power and six cylinder refinement in a purpose-built package. With massive pulling power spread widely across the engine's speed range, the 2.8 V-6 Turbo generates more torque than most other six cylinder gasoline engines in the Saab 9-3's market segment.

Saab Automobile Powertrain's expert knowledge and experience of turbocharging is recognized by its role as a Center of Expertise within General Motors for the development of turbocharged gasoline engines. The Swedish engineers were closely involved during the conceptual design and development of GM's new global V-6 engine architecture, ensuring it included the possibility of a turbocharged application.

Sophisticated technology

The 2.8 V-6 Turbo has a 60º vee-angle between its cylinder banks for perfect balance and combines excellent multi-valve refinement with outstanding performance. The all- aluminum construction provides a light and compact architecture, well suited to its transverse, front-wheel drive installation in the Saab 9-3 Aero. The cylinder heads, each with double chain-driven overhead camshafts operating four valves per cylinder, are of high-specification aluminum and unique to this turbocharged variant. The design ensures enhanced heat resistance under 85 bar cylinder pressures, as well as minimum maintenance costs. Also unique are pistons with hard anodized ring grooves for durability and under-skirt oil jet cooling, together with steel con-rods that are strengthened by sinter-forging, a process that involves molding metal in a powered form. The exhaust valves are filled with sodium to further enhance cooling. The cylinders have cast iron liners and a bore/stoke of 89.00 / 74.8 mm. For improved engine breathing, variable cam phasing on the inlet side is electronically controlled and hydraulically actuated, allowing continuously variable adjustment through 50º of crankshaft rotation. On the road, this translates to a more flexible power delivery and better fuel economy under different engine loads. A die-cast aluminum oil sump is designed to increase structural stiffness and the strong, four-bearing crankshaft is made from micro-alloy forged steel, a specification more commonly seen in competition performance or diesel engines. The twin-scroll water-cooled TDO4-15TK turbocharger operates at 0.6 bar maximum boost with intercooling and an integral by-pass valve. It is mounted centrally above the transmission and fed by both banks of cylinders. The use of two separate inlet tracts, one for each cylinder bank, separates the exhaust gas pulses, improving gas flow, reducing energy losses and raising turbocharger efficiency. The turbine wheel is made from a special high-grade steel alloy, commonly used in the turbocharged engines of world championship rally cars, which is resistant to erosion, cracking and creeping under high temperatures and centrifugal forces. Also unique are double-skin exhaust manifolds, which are hydroformed with stainless steel liners to improve cold start emissions by minimizing heat absorption to the manifold. Air injection into each manifold for up to 30 seconds after a cold start also helps the central pre-catalyst, positioned upstream of the main catalytic converter, achieve light off - its effective working temperature - as early as possible.

Smart engine management