Next month Vauxhall will aim upmarket in an attempt to hold its own in the fiercely contested medium-size family car sector.
The new Astra must not only fight off traditional rivals – the new VW Mk IV Golf and Ford’s Escort replacement due in the autumn – but new entrants from the so-called premium manufacturers: Audi with the A2, Mercedes’ A-class, and BMW’s 3-series Compact.
Add to this the conflicting demands for ever-increasing levels of equipment, meaning extra weight, and the need for fuel economy, and the challenge facing medium-car designers is severe.
The rivals have adopted various strategies to differentiate themselves in the face of this challenge, though only Mercedes went for a clean-sheet approach. VW seemed to decide to leave well alone with the Golf. The new Escort (whether it will keep the name is still undecided) is expected to use another variation on its so-called ‘new edge’ styling theme seen in the Ka and the Puma.
With the Astra, Vauxhall’s strategy is to confront the upmarket usurpers head on. The new model’s styling is a radical departure from the previous Astra, though it still includes characteristic Vauxhall details.
‘Compared with the old Astra we’ve deliberately tried to create a premium look,’ says Nick Reilly, Vauxhall’s chairman and managing director. With the new styling, he believes, ‘we have taken it to the top of the segment’. Though he will not be drawn on other manufacturers’ strategies, he says: ‘We feel it’s pretty risky to be seen as quirky.’
The new car will be built at Ellesmere Port on Merseyside where Vauxhall is investing £300m, as well as Antwerp in Belgium and Bochum in Germany. It will be available as a hatchback and estate from launch, with a saloon from September. An MPV will follow next year to compete with the Megane Scenic, but Vauxhall’s challenger will have three rows of seats.
Vauxhall says the new car aims to combine the Astra’s traditional attributes of space, economy and safety with the virtues of the new look, better dynamics making it more sporty to drive, and greater refinement.
More space is achieved through a class-leading wheelbase, up 90mm on the old model. For economy, a new 16 valve, 1.2 litre Ecotec engine, a four-cylinder version of the Corsa’s three-cylinder unit, will be offered from September. Other engines will include an eight valve 1.6 litre, a 16 valve 1.8 litre and a 2 litre turbo diesel. There will be a 2 litre GSi in the autumn and a high-performance Lotus-badged version is likely.
A stiffer bodyshell – the torsional stiffness of the hatchback is 80% greater than the outgoing model – contributes to improved refinement, handling and safety. Front and side impact protection has been improved and the Astra gets Vauxhall’s patented collapsible pedal box first seen in the Vectra.
Considerable attention has been paid to the chassis design and dynamics, partly in response to criticism of the Vectra. Lotus Engineering was brought in to fine tune the suspension design: it proposed changes to the dampers to give better body control, particularly on the UK’s more demanding roads, and other modifications to improve steering response.
‘We’re planning to do more damping work on UK roads because we’ve found the outcome is good for other parts of Europe too,’ says Heribert Roth, chassis development engineer. The potential of the Astra chassis for further development is behind the plan for the Lotus version.
Vauxhall’s DSA (dynamic safety) front suspension geometry, which aids stopping in a straight line under difficult road conditions, is carried over from the Vectra and Omega. It is designed to prevent sudden turning motions when braking on surfaces where one front wheel is on a slippery surface and the other has a good grip. Normally there is a tendency to steer towards the side with better grip. The Astra’s suspension is designed so that the wheel with better grip automatically toes in to compensate. The greater the braking force, the greater the compensation.
At the rear Vauxhall has developed a new, patented suspension geometry. It is based on a single tubular member, circular in cross-section at each end, with an open U-section in the centre. Roth says it has numerous advantages. It dispenses with the need for a separate anti-roll bar; apart from the cross-member only two links are needed for location.
Roll stiffness can be increased by increasing the wall thickness of the tube. Under roll the system gives a toe-in to the outer wheel, making for increased stablility in lane-change manoeuvres.
Roth says the system can be easily tuned for cars of different weights. And, by changing the orientation at which the tube is installed, cornering behaviour can be changed. Rotating the member anticlockwise increases the tendency to understeer; turning the opposite way increases oversteer.
At the front the suspension and steering components are mounted on a separate subframe consisting of a hydroformed tube with a welded cross-member. ‘This is solid enough to decouple from the underbody,’ says Roth. Six bushes insulate it from the underbody so the occupants are doubly insulated from bumps in the road, first by the control arm bushes and second by the subframe ones.
‘The old Astra had a subframe but it was open at the front and bolted to the underbody solidly,’ he says. In addition the tie rods and steering gear are mounted on the subframe, contributing to more precise steering response.
Aerodynamics of the new car are claimed to be class leading, in the quest for better fuel economy. Aerodynamic drag is ‘dramatically lower’, says Michael Kaufmann, group leader for aerodynamic body design, despite a greater frontal area.
‘We knew the frontal area would increase. We had to compensate. The key was to get in right at the start when influence on the design could be maximised. At the first big meeting, even before the concept design, we had a model to show which way to go to achieve the target,’ Kaufmann says. ‘We worked very closely with the styling people right through the process. The key is to get a lot of information early when you can influence nearly everything.’
Aerodynamic details include a front lip spoiler, unpainted and flexible so it will not be damaged if it touches the ground. A spoiler integrated into the trailing edge of the bonnet diverts the airflow above the windscreen wipers. A roof moulding, extending from the A-pillar for the length of the roof, incorporates the rain gutter and stops salt water from winter roads getting on to the side windows and reducing visibility.
The gap between the door mirrors and the car body channels air over the side windows to remove any drops of water which gather while the car is stationary. The wheels and hubs are designed so that whatever size wheel is fitted, the outer plane of the wheel is in line with the body sides, reducing drag.
At the rear engineers have eliminated the need for the spoiler above the rear window, instead integrating one into the shape of the ledge below the window. The air flow does not separate from the car body until the bottom rather than the top of the rear window, keeping it clean. Kaufmann says the rear wiper should not be needed during driving.
The fact that aerodynamic features are the same throughout the range will appeal to fleet buyers: ‘This will optimise fleet fuel consumption,’ says Kaufmann.
Vauxhall is confident it has come up with the right answer with the new Astra. ‘We believe it will be very positively received by current owners, but will also allow Audi and BMW owners to consider it who wouldn’t have done so before,’ says Nick Reilly. ‘We believe it will appeal to a whole group of customers who like a premium car, without premium prices.’
Whatever happens, the new model will have a fight on its hands.