Commodore-type power for new Astra
High performance has long been a keynote for the Holden brand, and even though its big rear-drive Commodore models are due to be axed when the company ceases production in two years, the performance credo will continue.
Latest in a long line of Holden performance models is the newlyreleased Holden Astra VXR, a beautiful four-seat coupe based on the Germanbuilt Opel Astra OPC that manages to mix practicality with out-and-out fun!
As always, the heart of any car is its engine, and the one that beats in the Astra VXR is nothing less than a 206kW two-litre turbocharged direct injection which achieves maximum torque of 400Nm and can sprint from zero to 100km/h in six seconds and on to a top speed of 250 km/h. To put this into perspective, that’s only 2kW less power and 50Nm MORE torque than found in the 3.6-litre V6-powered Commodore SV6, and only 52kW less than the mighty six-litre Commodore SSV V8!
The VXR’s four-cylinder engine offers 25 percent more maximum torque than the previous Opel Astra OPC and also boasts 30kW more power. This translates into 104kW/litres (140 bhp/ litre), the highest specific output per litre in any Holden production car.
Although based on the previous engine, the latest version has much better fuel economy, reduced by 12 percent, while CO2-emissions have been reduced by 14 percent. The CO2-emissions of the Astra VXR have been lowered to 189 g/km and fuel consumption to 8.1L/100km.
There’s a completely new state-ofthe-art engine air intake system to feed as much air to the turbocharger as possible. In addition, the exhaust system was optimised to further improve the flow of the exhaust gases and improve the engine performance. The turbocharger itself was further enhanced to withstand even more charge air pressure and was increased by using new components.The engine’s high thermal endurance is further supported by a water jacket which extends to the bottom of the cylinders, and oil-spray cooling of the underside of the pistons.
Both camshafts respond automatically via an electro-hydraulic cam phaser to match valve opening times to the engine load status via the engine control unit. In addition, a higher overlap at lower speeds with continuously variable camshaft phasing ensures the turbocharger responds more quickly.
The outlet valves are sodium-filled and all valves are actuated via low friction roller valve levers.
Other engine features are two counter-rotating balance shafts, low-maintenance chain drive for the camshafts and a cast-on oil filter housing, which is easily accessible from above.
An oil change simply requires replacing the cartridge and is signalled by an interval indicator. Sensors measure wear and tear of the fully synthetic lubricant according to parameters such as the number of cold starts and the number of ignition.
Opel designed a high performance chassis package geared especially towards lateral dynamics and superb handling qualities for the Astra VXR, to complement its powerful engine.
The chassis benefits from several decisive elements that all enhance the car’s driving dynamics:
High performance struts (HiPerStruts) on the front wheel suspension, the mechatronic FlexRide chassis system, a mechanical multi-plate slip differential and Brembo brakes.
The FlexRide chassis system lets the driver sharpen the characteristic shock absorber line, the steering and the gas pedal responsiveness. He can choose between three different modes, with each mode offering a unique and specific experience of high performance driving. The Standard mode delivers all-round performance while comfort is preserved at all times for everyday drive situations.
At the touch of a button the Sport mode stiffens the chassis suspension, increases agility by reducing body roll, and makes the steering more direct. Meanwhile, the VXR mode creates the ultimate driving experience: steering becomes even more direct in comparison to the Sport mode, the throttle is more responsive and the chassis setting is geared towards delivering maximum performance.
In addition, a Watt’s link which has been tried and tested in motor sports has been fitted to the rear axle of the Astra VXR and is combined with a compound-crank axle, ensuring superb lateral stability and steering precision, especially in bends.
The linkage comprises a short, pivoting centre link with a ball joint at each end to which the lateral links from the wheels are bolted. The system ensures that around 80 percent of all lateral loads are absorbed by the rear suspension.
The 19-inch alloy wheels that come as standard add a further sporty note to the car. In addition, the engineers finetuned the chassis to VXR standards by modifying the dampers and stiffening the springs and bushings.
In addition, the Astra VXR has been fitted with a mechanical multi-plate limited slip differential on the front axle which brings maximum torque to the road. The differential, which contains several clutch plates, helps to reduce wheel slip when there are very high lateral forces under acceleration, for example, or changes in the texture of the road surface. It is also ideal for excursions onto the race track.
The coordination of the differential with a static basic locking torque guarantees a harmonious response and transition behaviour between load and overrun, eliminates influences on the steering and self-steering behaviour during overrun, and ensures traction reserves in the case of highly varied wheel loads.
The ESP stability control in the Astra VXR offers three different modes which allow the driver to determine how challenging and sporty he wants to drive.