timing enables most of the increase in power from the L37 and LD8 Northstars. LC3 A supercharged Northstar was used in the 2006 Cadillac STS-V and Cadillac XLR-V. The bore was reduced for increased strength and improved head gasket sealing. Variable valve timing is used on both the intake and exhaust sides. The STS-V engine produces at 6400 rpm and at 3900 rpm with 9.0:1 compression and the XLR-V engine produces at 6400 rpm and at 3900 rpm. L47 The L47 Aurora engine was a special V8 designed for the Oldsmobile Aurora, based on the Northstar engine, used during the 1995-1999 and 2001-2003 model years. It is a DOHC V8 which produced and of torque. The bore and stroke was . The L47 had a 10.3:1 compression ratio and used premium fuel. Although most of the Northstar's features, including the coolant loss system, remained intact, the decreased bore increased weight unacceptably. To reduce it, Oldsmobile used a one-piece glass-filled thermoplastic intake manifold and simplified AC Rochester sequential fuel injection. A new die-cast structural aluminum oil pan incorporated baffling to reduce oil starvation in hard driving. A starter interlock prevented the starter from engaging if the quiet L47 was already running. An early version or prototype of this engine was used in the 2nd generation Oldsmobile Aerotech. A highly modified version of this engine was used by General Motors racing division initially for IMSA sports car competition in an Oldsmobile Aurora GTS-1 and Riley&Scott LMP prototypes in 1995, Indy Racing League competition starting in 1997, then was later used in the Cadillac Northstar LMP program in 2000. Both engines retained the 4.0 L displacement, but the Northstar LMP version was twin-turbocharged. The Aurora was also used in the Shelby Series 1 car. In the inaugural DTM season, Opel would debut their Astra with a V8 derived from the L47. The Aurora engine was introduced in 1994 for the 1995 model year, and General Motors has not used this engine since the retirement of Oldsmobile in 2004. LX5 (Shortstar) The LX5 is a DOHC V6 from Oldsmobile, introduced in 1999 with the Intrigue. It was produced by the Premium engine group at GM and was thus called the Premium V6, or PV6, while it was being developed. It is based on the L47 Aurora V8, which is itself based on the Northstar engine, so engineers called it the Short North, though Oldsmobile