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Opel Astra GTC exclusive high-performance chassis

The compact coupe launched by Opel has created much excitement in June, when he could be ordered. Dramatic aspect of the GTC, created under the direction of Mark Adams, Vice President Design of Opel / Vauxhall, is meant to wow customers and beat well-known leaders in its class.

But the appeal goes beyond the lines GTC confident. Unlike many other compact three-door hatchback versions of existing GTC, like the previous version, will be unique in the Opel range, is designed for drivers who appreciate both handling and performance, and appearance of a vehicle.

To do this, Opel engineers in Rüsselsheim and the Vauxhall Engineering Center in Millbrook, United Kingdom created a special platform for the GTC. Key components such as front-HiPerStrut suspension were taken from the Insignia OPC with 239 kW/325 hp, while single-arm rear axle shaft Watt compound was significantly improved. So, although GTC range currently comprises a wide range of engine power to 88 kW/120 hp to 132 kW/180 hp, drivers can always rely on a high level of driving dynamics.

High-tech front suspension enhances the attractiveness of the GTC

Since the early development of the GTC program, the goal was to provide driver-oriented car features and adaptability to road conditions. "Our goal was that through the dynamic leadership of the GTC to beat the best car in its class," said Michael Harder, supervising engineer of the Division of dynamic management of Opel. "We wanted also to change the focal point for the Astra 5-door, namely cornering response and damping behavior, focusing on a more precise configuration, but quite comfortable for most roads in Europe and the UK. "

Most of the development process focused on the integration HiPerStrut suspension from Opel in the GTC, a first for an Astra. Based on the system currently used in the Insignia OPC with 239 kW/325 hp, the suspension mounting points using existing HiPerStrut, but reduce the angle of inclination of the axis pivosilor 44% and reduces the length by 46% compared linchpin models equipped with MacPherson strut suspension . This helps prevent skidding due to steering torque generated a strong feature of many automotive front-wheel drive, allowing drivers to better exploit the performance of the GTC, without affecting the accuracy of direction.

Use HiPerStrut suspension reduced, also the variation of camber of the front wheels during cornering GTC, improving adhesion. Steering system behavior is also improved due to reduced friction levels recorded between its components. Changes caused by the suspension geometry allows HiPerStrut also equipped with wheels GTC diameter to 20 inches.

"The present Astra 5-door always presented exceptional handling," said Michael Harder. "But GTC raised the bar higher. The driver will appreciate the instant response and grip, allowing them to exploit further the potential Astra platform."

Revisions complete rear suspension ride height modifications and track GTC

Unlike Astra 5-door version, the ride height of the GTC was lowered by 15 mm, while the wheelbase has been increased by 10 mm from 2685 mm to 2695 mm. Both gauges are also wider, 1.584 mm (40 mm) front and 1585 mm (+30 mm) rear.

The rear compound crank arm Watt was also revised to achieve exceptional results in terms of roll stiffness and roll center height. The system has many advantages over a configuration with multiple arms, including an improved design, greater rigidity of the wheel camber and low friction suspension system. Watt arm rear axle also allows, maintaining constant lateral stability.

Watt arm rear axle is located on a small cross, attached to the underside of the vehicle, behind the center line of rear wheels. It includes a central arm with a swivel ball joint at each end, which arms are mounted to the side wheels.

On straight roads, the configuration provides excellent stability, but during cornering it minimizes lateral deviation, as a system with multiple arms. Opel engineers estimated that nearly 80% of arms absorb lateral loads on the rear suspension. In addition, Watt allows more flexible fitting sleeves, without having to compensate the angle of convergence of the rear wheels, providing an improved response and a high level of comfort on the rear axle.

A unique direction for the GTC

Accuracy, response and reliability: these were the three elements of the program targeted specifically to design the steering GTC. The challenge was represented by maintaining ease of use of the system at low speeds, but involvement of a greater level of involvement and a greater effort at higher speeds.

Astra GTC uses a rack and pinion steering with speed-sensitive help system. But for the steering system to provide drivers a greater response, the electric motor is mounted directly on the rack system and not the steering column.

The most important benefits of using power steering is well known. At low speeds, the assistance is increased to minimize the effort. At higher speeds, the degree of assistance is automatically reduced to ensure greater system response driver steering. The second important benefit is reduced fuel consumption, because it does not require a hydraulic pump and responds directly to the power needed at any speed.

FlexRide further enhances the attractiveness of the GTC for drivers

Astra GTC chassis was designed to integrate perfectly intelligent, adaptive chassis control FlexRide. This increases stability while driving, cornering behavior and response steering system automatically adapting to road conditions, speed cornering, vehicle movements and individual driving style. Improved ride and balance of the car also increase the level of safety in emergency situations. In addition, FlexRide offers three different settings, allowing the vehicle characteristics change with the push of a button: you can choose anywhere from Standard balanced way, how "Tour" mode designed for comfort or "Sport."

Road accidents: the ultimate challenge for engineers designing chassis

"The road network in the UK is different from any other in Europe," said Gary Baker, chief of dynamic Vauxhall Engineering Center. "Of course, we test the vehicles in many different countries, but coils and highly inclined roads in the UK often reveal that handling characteristics remain otherwise hidden surfaces more uniform and predictable roads on the continent. And it's not just surfaces. curves with variable radius are common in the UK, such as ridges and peaks and hidden from view, requiring even more of our vehicles and drivers. A good example would be a driver who has to make an adjustment during a turn way that is not normal curve where it narrows and releases the accelerator pedal or brakes suddenly. The vehicle must respond appropriately and intuitively to the driver's steering commands, but must be fun driving in normal conditions. "

Because drivers are not always uniform access to roads, winding, and the GTC was set to face the most difficult and rough surfaces, even when equipped with wheels 19 and 20 inch available as an option (standard model is equipped with 18-inch wheels).

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