2004 Northstar V8 Sets New Standard For Cadillac XLR and SRX
GM Powertrain's 2004 Northstar V8 Sets New Standard
Cadillac XLR and SRX to Benefit from Next-Generation Northstar Performance and Refinement Improvements
WARREN, Mich. -- When Cadillac debuted the Northstar V8 engine in the 1993 Allanté, it quickly became a benchmark for sophisticated performance. GM Powertrain has taken the Northstar 4.6-liter, dual-overhead-camshaft (DOHC) V8 to a higher level of performance and refinement by developing a next-generation version of the highly regarded engine for the 2004 Cadillac XLR and SRX. The next-generation Northstar is the first adaptation to rear-wheel-drive (RWD) and all-wheel-drive (AWD) configurations.
"The next-generation Northstar was extensively re-engineered to provide drivers with a technologically advanced powerplant that will establish a new benchmark for luxury vehicles in performance, refinement and the total driving experience," said John Zinser, GM Powertrain Northstar chief engineer. "We want our customers to experience the full exhilaration of driving, which includes performance and acceleration plus the feel of the road, sound of the engine, and a strong sense of being in control and in touch with the driving experience.
"This new Northstar does just that with smooth, refined performance throughout its entire operating range. It is quiet, yet tuned to give the driver feedback from the environment. It operates even more cleanly and efficiently than its predecessors with excellent reliability and durability."
While refined operating characteristics were a priority in developing the new Northstar, the overall goal was exceptional performance. The performance targets are best exemplified by the XLR roadster: 0-60 mph acceleration in under six seconds; the quarter mile in less than 14.7 seconds, and a top speed of 155 mph, the industry's voluntary limit for high-performance cars.
In both new Cadillac models, the Northstar delivers a higher output across the entire operating range with targeted output of 315 horsepower (235 kW) @ 6400rpm and 310 lb-ft (420 Nm) of torque @ 4,400 rpm. In addition to these peak values, new four-cam continuously variable timing has freed the engine from the traditional constraints of fixed-cams that can only provide either high horsepower or high torque.
The Northstar also has an increased 10.5:1 compression ratio. While premium fuel is recommended for maximum performance, it can be operated on regular unleaded fuel.
New Technology and Design Features
The Northstar V8 is a 90-degree, DOHC, four-valves-per-cylinder engine featuring an aluminum block and cylinder heads, and a valvetrain configuration with roller finger followers. While maintaining these basic features, the new RWD version provides a host of Northstar "firsts," new technologies and design features to position it as a segment leader:
- Four-cam continuously variable valve timing (VVT).
- Polymer piston skirt coating allows a tighter fit, minimizing piston-to-bore noise potential. A larger piston pin helps dampen internal noise.
- The steel crankshaft increases stiffness over more conventional cast-iron crankshafts.
- Cast iron manifolds absorb noise more readily than fabricated manifolds.
- The first longitudinal application of the 4.6-liter Northstar V8 . To optimize coolant and oil flow for the new application, the water pump was moved to the front of the engine, which required changing all of the coolant passages and engine cavities - in effect, a virtual redesign of the block and heads.
- A specifically designed acoustic cover over the engine for more complete radiated noise containment. The cover, in addition to providing measurable noise reduction, maintains the attractive, neat and orderly underhood harmony of the previous Northstar's installations. Any components not shielded by the cover have been carefully reviewed for finish and corrosion resistance.
- Cartridge block heater with "dry" installation to eliminate potential coolant leaks. The heater, which can be added for faster warm-ups in extremely cold weather, fits into a compartment outside the coolant passageway (rather than within the coolant circulation system) to eliminate any potential leaks.
|Configuration||4.6L V8||Horsepower||315 @ 6400 rpm|
|Bore x stroke||93 mm x 84 mm||Torque (lb-ft)||310 @ 4400 rpm|
|Displacement||4565 cc||Fuel system||Sequential fuel injection|
|Valvetrain||DOHC 4 valves per cylinder||Cylinder block||Aluminum|
|Compression ratio||10.5:1||Cylinder heads||Aluminum|
GM Powertrain is a global producer of engines, transmissions, castings and components for GM vehicles and other automotive, marine, and industrial OEMs. Headquartered in Pontiac, Mich., GM Powertrain has operating and coordinating responsibility for GM's powertrain manufacturing plants and engineering centers in North America, South America, Europe, and the Asia-Pacific region.