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[edit] L47

A L47 inside an Aurora's engine bayThe L47 Aurora engine was a special V8 designed for the Oldsmobile Aurora, based on the Northstar engine. It is a DOHC 4.0 L (3995 cc) V8 which produced 250 horsepower (186 kW) and 260 ft·lbf (353 N·m) of torque. The bore is 87 mm and the stroke is 84 mm. The L47 has a 10.3:1 compression ratio and uses 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 prevents the starter from engaging if the quiet L47 is already running.

A highly modified version of this engine was used by General Motors racing division initially for Indy Racing League competition starting in 1995, then was later used in the Cadillac Northstar LMP program in 2000. Both engines retained the 4.0 L capacity, but the Northstar LMP version was twin-turbocharged.

The Aurora engine was introduced in 1994 for the 1995 model year, and General Motors has not used this engine since the demise of the marque in 2004.


[edit] LX5

A "Shortstar" LX5 inside an Intrigue's engine bayThe LX5 V6 is a DOHC engine from Oldsmobile, introduced in 1999 with the Oldsmobile 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 fans have taken to calling it the Shortstar.

It is not a simple cut-down V8. Although it has a 90° vee-angle like the Northstar and Aurora, the engine block was engineered from scratch, so bore centers are different. It has chain-driven dual overhead cams and 4 valves per cylinder, but is an even-firing design with a split-pin crankshaft similar to the modern GM 3800 engines. The LX5 displaced 3.5 L (3473 cc) and produced 215 hp (160 kW) and 230 ft·lbf (312 N·m). Bore is 89.5 mm and stroke is 92 mm.

The cost of building this engine was high, and it was not used in many vehicles. It was said at the time that a family of premium V6s would follow, with displacements ranging from 3.3 L to 3.7 L, but only the LX5 was ever produced. It was entirely different from any other V6 in the GM inventory, and as with the Aurora V8, production stopped with the demise of Oldsmobile.

This engine was used in the following:

1999-2002 Oldsmobile Intrigue
2001-2002 Oldsmobile Aurora
The 3.5L LX5 was on the Ward's 10 Best Engines list for 1999 and 2000.