Aero models have a 2.8-liter turbocharged V6. This 24-valve, DOHC engine, known as the LP9, is part of GM's High Feature family, manufactured in Australia. It is all aluminum, with a forged steel crankshaft and connecting rods, a variable intake manifold, and continuously variable timing for both the intake and exhaust valves. The version in the 9-3 has a compression ratio of 9.5:1 and an intercooled, twin-scroll turbocharger, with a separate inlet from each cylinder bank to reduce turbo lag. In 2008, Saab raised maximum boost pressure from 7.3 psi to 11.6 psi, increasing output to 280 horsepower and 295 lb-ft of torque.