AURA PERFORMANCE HIGHLIGHTS

[Northstar]

SATURN AURA PERFORMANCE HIGHLIGHTED BY 3.6L V-6 VVT AND NEW SIX-SPEED AUTOMATIC TRANSMISSION

NEW YORK – The Saturn Aura sport sedan brings a new level of refinement and driving fun to the segment. Aura is built on GM’s global midsize car platform, which features a strong chassis and robust body structure that enables nimble, precise handling and enhances crashworthiness.

Chassis and suspension highlights:

• 112.3-inch (2,852 mm) wheelbase

• MacPherson strut front suspension with direct-acting stabilizer bar

• Four-link independent rear suspension

• Hydraulic power-assisted rack-and-pinion steering

• Four-wheel disc brakes with four-channel ABS

• Family of 17- and 18-inch wheel-and-tire combinations

Aura is powered by either a 3.5L V-6 with variable valve timing (VVT) or a more powerful 3.6L DOHC V-6 with VVT. The 3.5L is backed by an efficient four-speed automatic, while the 3.6L engine is matched to a new Hydra-Matic 6T70 six-speed automatic – the first GM vehicle to receive this new, fuel-saving transmission.

3.6L V-6 VVT

The GM 3.6L V-6 VVT is standard in the Aura XR; it is rated at 252 horsepower (188 kw)* at 6300 rpm and 251 lb.-ft. of torque (340 Nm)* at 3200 rpm. The 3.6L V-6 is a state-of-the-art, DOHC engine jointly developed at GM technical centers in Australia, Germany, Sweden and the United States. It debuted in the Cadillac CTS sedan and SRX crossover vehicle. The engine uses full four-cam phasing, rapid date processing and torque-based engine management to optimize power, economy and emissions performance.

Full four-cam phasing of the variable valve timing system ensures linear delivery of torque across the engine’s rpm band, while features such as electronic throttle control deliver crisp, immediate response and feedback. The engine uses electro-hydraulic vane-type phasers to rotate the camshafts relative to the cam-drive sprockets, allowing infinitely variable combinations over a range of 50 degrees.

Additional engine features include:

• Aluminum cylinder block with iron cylinder sleeves

• High-flow aluminum cylinder heads

• Four valves per cylinder

• Dual-stage variable intake manifold

• Sequential dual spray port fuel injection

• Coil-on-plug ignition system

• Electronic throttle control with integrated cruise control

The aluminum-intensive 3.6L V-6 also is designed to deliver smooth, quiet performance with durability. The camshaft drive incorporates a new, smaller pitch chain, which provides quieter operation. Other elements, including the cam covers, intake manifold and direct-mounted accessories are designed to reduce or eliminate conventional points of noise, vibration and harshness. A long operating life is driven by heavy-duty and special components, such as a forged steel crankshaft, polymer-coated pistons and oil jets that drench the bottom of the pistons with cooling, lubricating oil.

Hydra-Matic 6T70 automatic transmission

The new Hydra-Matic 6T70 electronically controlled, six-speed automatic transmission is matched with the Aura XR’s 3.6L V-6. It is an advanced transmission with state-of-the-art clutch-to-clutch shift operation, designed for high-performance front-wheel drive applications. Clutch-to-clutch operation allows for reduced complexity and compact packaging. A wide, 6.04:1 overall ratio helps the transmission deliver both performance and fuel economy – enabling up to 8 percent improved performance and up to 4 percent improved fuel economy when compared with current front-wheel drive four-speed automatics.

The 6T70’s six-gear configuration allows for a “steep” 4.48:1 first gear, which helps deliver exceptional launch feel, and a 0.74:1 overdrive sixth gear. This “tall” overdrive gears lowers rpm at high speed, reducing noise, vibration and harshness. The transmission’s fifth gear is 1:1 direct drive. Shorter steps between the gears, compared with a four-speed automatic, enhance performance and feel, as the transmission quickly finds the best gear for the vehicle speed and road conditions. Also, the transmission offers the capability of driver shift control (DSC), which allows the driver to use tap-up/tap-down shifting to select the desired gear for specific conditions, such as downhill grades where lower gears can take advantage of engine braking.

3.5L V-6 VVT

The Aura XE’s 3.5L V-6 with VVT is rated at 224 horsepower (167 kw)* at 5900 rpm and 220 lb.-ft. of torque (298 Nm) at 4000 rpm.* Perhaps the most significant technological feature of the new 3.5L V-6 is the adaptation of variable valve timing – a first for cam-in-block engines. The system incorporates a vane-type camshaft phaser that changes the angular orientation of the camshaft, thereby adjusting the timing of the intake and exhaust valves to optimize performance and economy, and help lower emissions. It offers infinitely variable valve timing in relation to the crankshaft. The cam phasing creates “dual equal” valve timing adjustments – the intake valves and exhaust valves are varied at the same time and at the same rate.

The 60-degree configuration of the 3.5L engine is naturally balanced, ensuring drivetrain smoothness and eliminating the need for balance shafts. The engine differs from previous GM 60-degree designs with its offset cylinder bores, meaning the intersection of the cylinder bores’ centerline is not at the crankshaft centerline. Instead, the intersection is 3 mm below the crankshaft axis. This was done to allow packaging room for the relatively wide cylinder bores.

Additional technical highlights of the new 3.5L V-6 include piston-cooling oil jets, polymer-coated pistons, steel crankshaft, electronic throttle control, 58X Quick Sync ignition and high-flow aluminum cylinder heads. The engine is teamed with a Hydra-Matic 4T45 electronically controlled four-speed automatic transmission. Traction control is standard with this combination.

Chassis structure

The Aura’s architecture is a solid structure that enables a 26.8 Hz bending frequency – a rigid foundation that ranks with the world’s best luxury cars. Three integrated torque rings contribute much of the body structure’s strength. Tied into complementing structural members, the torque rings add stiffness-enhancing support to key areas of the architecture. The rear torque ring, for example, ties the package tray horizontally to structural members on opposite sides of the chassis. This not only enhances overall strength, but still allows a generous rear-seat pass-through from the trunk.

Another one of the torque rings includes the magnesium cross-car beam that forms the foundation for the instrument panel. This “mag” beam is lightweight, but extremely stiff, and contributes greatly to Aura’s solid feeling behind the wheel and side-impact crash protection. In addition to the torque rings, the structure also benefits from extensive use of high-strength steel (HSS) – comprising approximately 60 percent of underbody components. It is used primarily in critical areas, including the front and rear structures, longitudinal rails and rocker panels. HSS also is used in a strong, reinforcing “backbone” that forms the floor’s center tunnel. Rather than just a single layer of sheet steel, the tunnel has an extra piece of HSS welded between it and the floor pan, running the length of the tunnel.

Ride and handling

With a strong structure, the ride and handling attributes of the Aura were tuned during development to a high degree of precision because chassis flex wasn’t a primary concern. Large-car suspension proportions – 112.3-inch (2,852 mm) wheelbase and approximately 60-inch (1,524 mm) front/rear tracks – packaged within midsize vehicle dimensions also enable a smooth ride and firmly-planted handling traits.

Aura has fully independent front and rear suspensions, including a MacPherson strut front suspension, with direct-acting stabilizer bar, and a four-link rear suspension. The front suspension is carried by a perimeter-type chassis cradle assembly, which consists of a U-shaped hydroformed steel tube welded integrally with a rear cross member. The cradle is isolated from the chassis by four widely spaced rubber mounts that dampen noise, vibration and harshness.

Handling is augmented in the Aura XR with standard StabiliTrak electronic stability control. The system uses a yaw sensor, lateral accelerometer and steering angle sensor to help keep the vehicle under control in the most challenging driving conditions. The system applies braking at any of the four wheels as required to help maintain control.

All models feature standard four-wheel disc brakes with standard four-channel ABS. Braking capability is enhanced with large, vented front discs and Dynamic Rear Proportioning (DRP). With DRP, improved stability and braking during cornering results from the use of independent rear control. DRP also allows more effective use of the rear brakes as vehicle loading changes.

The Aura’s hydraulic power-assisted rack-and-pinion steering system is tuned to provide sharp, immediate responsiveness and a linear, direct feel at all speeds. Aura’s ride and handling traits are conveyed to the road via standard 17-inch wheels and tires on XE and 18-inch wheels and tires on XR. Full wheel covers are standard on XE, with machine-face alloy wheels available. Aura XR’s 18-inch wheels feature an ultra-bright finish.

*Pending SAE certification. A new voluntary power and torque certification procedure developed by the SAE Engine Test Code committee was approved March 31, 2005. This procedure (J2723) ensures fair, accurate ratings for horsepower and torque by allowing manufacturers to certify their engines through third-party witness testing. GM was the first auto manufacturer to begin using the procedure and expects to use it for all newly rated engines in the future.

[ponchoman49]

Quote: The 60-degree configuration of the 3.5L engine is naturally balanced, ensuring drivetrain smoothness and eliminating the need for balance shafts. The engine differs from previous GM 60-degree designs with its offset cylinder bores, meaning the intersection of the cylinder bores’ centerline is not at the crankshaft centerline. Instead, the intersection is 3 mm below the crankshaft axis. This was done to allow packaging room for the relatively wide cylinder bores.

I don't like the sound of this. The last engine that had offset cylinder bores was the infamous 3.8 liter 231 cid carbed Buick V6 from 1978-1988 and we all know what a pile that was. We used to pull many of those engine apart and noticed that the cylinders had excesive wear in every darn one of them because of the offset bores which increase latteral side to side wear on the cylinders. It will be interesting to see how these motors hold up in the real world.

[me3head]

Wheel Covers ?!?!?!

[avro206]

Glad to see they got the 3.6L to more then 250hp.

Very surprised at the 3.5L hp outptut. They should upgrade every application of the3500 to these specs. Aura looks great!!

[ponchoman49]

Wheel Covers ?!?!?!

Yup, just like on base and mid level Camrys, Accords, Sonotas, Fusions, G6's and Malibus etc.

[Petra]

If only I could get the 6-Speed Manual from the CTS, I would be sooooooooo sold. *sigh*

[avro206]

If only I could get the 6-Speed Manual from the CTS, I would be sooooooooo sold. *sigh*

CTS is RWD--the Aura would need a fwd trans---one from the GTP would work....

[Drew Dowdell]

Quote: The 60-degree configuration of the 3.5L engine is naturally balanced, ensuring drivetrain smoothness and eliminating the need for balance shafts. The engine differs from previous GM 60-degree designs with its offset cylinder bores, meaning the intersection of the cylinder bores’ centerline is not at the crankshaft centerline. Instead, the intersection is 3 mm below the crankshaft axis. This was done to allow packaging room for the relatively wide cylinder bores.

I don't like the sound of this. The last engine that had offset cylinder bores was the infamous 3.8 liter 231 cid carbed Buick V6 from 1978-1988 and we all know what a pile that was. We used to pull many of those engine apart and noticed that the cylinders had excesive wear in every darn one of them because of the offset bores which increase latteral side to side wear on the cylinders. It will be interesting to see how these motors hold up in the real world.

All the Volkwagen VR series engines and W series engines have offset bores. They run fine.

[I hope GMRULES again]

'' Hydraulic power-assisted rack-and-pinion steering "

Wonder why they chose this over EPS that other Epsilon cars use.

[Paolino]

'' Hydraulic power-assisted rack-and-pinion steering "

Wonder why they chose this over EPS that other Epsilon cars use.

Maybe to counter for the "vague" feeling in steering the other cars have gotten as reviews.

[Northstar]

'' Hydraulic power-assisted rack-and-pinion steering "

Wonder why they chose this over EPS that other Epsilon cars use.

There were numerous complaints about the EPS, and it really isn't responsive at all when you're driving. Hydraulic is much better, EPS was a good idea (possibly), executed poorly.