OVERVIEW & MARKET
Britain’s best selling UK-built car is re-born and revitalised
Launched at the 2009 Frankfurt Motor Show, Vauxhall’s all-new Astra is poised to raise the bar for compact cars sold in the UK, with a combination of stylish design, class-leading dynamics, ultra-efficient powertrains and upscale quality.
On sale now, and in UK showrooms from December, the new Astra will uphold Vauxhall’s tradition of offering buyers levels of innovation and technology normally found in a class above. New Astra prices start at £13,995 for the comprehensively equipped 1.4-litre, 87PS Exclusiv model and extend to £24,335 for the luxurious 2.0CDTi 160PS Elite automatic.
With a range of eight engines and five trim levels, the new Astra will initially be available as a five-door hatchback only, built at the Ellesmere Port plant in Cheshire, home to all Vauxhall’s compact-class cars since it opened 46 years ago.
Ellesmere Port will be responsible from launch for manufacturing all Astras sold across Europe, but UK buyers will take the lion’s share, amounting to 25 per cent of total production. Small wonder, then, that even in its outgoing form, the Astra is Britain’s best-selling UK-built car and one that is almost always seen in the top three sales listings.
What’s more, the Lower Medium Sector, in which the Astra sits, is hugely significant in the UK, accounting for 17.5 per cent of all retail car sales. With style-conscious buyers choosing Vauxhall more and more, the Astra has a large part to play in this success, along with its continued appeal to buyers in the fleet market.
“As with the Insignia, the Astra is an all-new car, continuing the transformation of the Vauxhall product range which started five years ago with the launch of the Mk 5 model,” said Andy Gilson, Vauxhall’s Marketing Director. “Also like the Insignia, the Astra aims to attract a new group of buyers, those who may never have considered a Vauxhall before, but now see cars like the new Astra as offering all the style and quality of a premium product, such as an Audi A3, but at a far more affordable price point. “
Mark Adams and his team execute yet another design masterstroke
With its strong, cab-forward silhouette, steeply raked windscreen and sloping rear roofline, the Astra makes ingenious use of many of the design features found in the Insignia, but in a fresh and innovative way. Also like the Insignia, it has spent over 600 hours in the wind tunnel, benefiting performance, economy and overall refinement.
“We’re continuing with the same premium design cues as the Insignia,” said Mark Adams, Vice President of Design for GM Europe. “However, the main design themes, liked the wing-shaped signatures and the blade, needed an individual execution to avoid ‘cloning’ the model ranges.”
Upmarket design, quality materials and clever packaging define new Astra’s cabin
Echoing the flowing forms of its bodywork, the new Astra’s interior marks a major shift towards premium design and quality in the compact sector. It employs the recurring wing and blade motifs that were first introduced in the Insignia and are now used in a fresh and innovative way.
Ambient lighting enhances the feeling of quality in the cabin, with lighting points framing the gearshift surround, the area above the centre console and within the door handle recesses, depending on trim level.
Unparalleled in this sector is the Astra’s raft of clever cabin storage solutions, some of which have even been patented. Rather than focusing on the compartment size alone, the Astra’s cabin is full of bespoke storage areas designed specifically for the 20 most common items buyers have been found to carry in their car, from an MP3 player to a 1.5-litre drinks bottle.
Efficient, yet powerful, Astra’s engines are low on C02 but high on power
The new Astra will be available with a range of nine engines, ranging from 87PS to 180PS, all of which offer impressive efficiency and an overall cut in emissions of 13.3 per cent compared with the current Astra range.
Diesel engines are expected to represent almost half of all Astra sales, and will range from a 1.3-litre producing 95PS to a 2.0-litre generating 160PS, but will never emit more than 129g/km when fitted with a manual transmission.
There will also be five petrol engines available, ranging from an 87PS 1.4-litre to a 180PS 1.6-litre Turbo. Included in this line up will be a new 1.4-litre turbocharged engine, producing 140PS, replacing the 1.8-litre motor used in the current range. This new powertrain perfectly illustrates Vauxhall’s engine downsizing philosophy which provides drivers with all the performance of a larger capacity engine, but with far fewer emissions.
Innovative Watt’s link rear axle equals fine dynamics and superior packaging
The new Astra’s front and rear tracks have been increased by 56mm and 70mm respectively, while its wheelbase has been increased by 71mm, the cumulative effect being improved handling and ride quality, as well as more space and comfort for occupants.
Continuing Vauxhall’s trend for innovation, its engineers have combined the size, weight and efficiency benefits of a compound crank rear axle with a cleverly positioned Watt’s link, which helps support lateral forces during cornering.
Complementing this system is a new version of Vauxhall’s FlexRide adaptive damping system, which adjusts the suspension character automatically depending on the driver’s needs, while also offering three programmable damper settings.
Finally, a core body structure, stiffer than that of the outgoing car, enhances the new Astra’s ride and handling still further, while also reducing noise and vibration inside the cabin.
Illustrating Vauxhall’s commitment to developing its cars specifically for British roads and drivers, the new Astra has bespoke UK steering settings developed in conjunction with the Vauxhall Engineering Centre, based at GM’s Millbrook Proving Ground in Bedfordshire.
Vauxhall brings technology and innovation to the compact class
While the Insignia succeeded in making new, high-tech innovations accessible in the mid-size sector, Vauxhall has set itself an even more ambitious goal in bringing most of these features to the compact sector with the new Astra. These include:
- Advanced Forward Lighting (AFL+) – Vauxhall’s third generation AFL+ which changes its intensity and reach to suit prevailing driving and road conditions using nine different light functions
- Ergonomic Driver’s Seat – featuring 6-way adjustment (4-way on front passenger seat), 4-way lumbar adjustment and an extendable seat cushion. Available on all trim levels, both the driver’s and front passenger’s seats provide enhanced support for overall body comfort.
- FlexFloor – provides flexible solutions to boot storage, and features a boot floor which is moveable and can be mounted in a choice of three positions according to owners’ needs.
- Flex-Fix – Vauxhall’s innovative bike carrier is integrated into the rear bumper. This optional feature, which slides out of the rear bumper like a draw, provides an easy and convenient method of transporting up to two bikes.
2. EXTERIOR DESIGN
- Design cues from much-praised Insignia reinterpreted for new Astra
- Sculptural shapes combined with sporty proportions
- Powerful shoulder-line and rakish profile re-define Vauxhall’s design language
The next generation Astra brings a new look to the compact class, with its strong coupe-like lines, elegant surfaces and its unique interpretation of Vauxhall’s design language.
At 4.42 metres the new Astra grows by some 17 centimetres compared with its predecessor, positioning itself right between the Corsa (4.0 metres) and the Insignia (4.83 metres). The wheelbase increases by 71 millimetres, improving rear passenger space and adding comfort for all occupants.
A slim but low trapezoidal grille incorporating the latest Griffin logo dominates the front of the car, while the familiar blade sculpted into the side panels of the new Astra sweeps upward and visually connects with the side window-line, balancing the car’s proportions.
Eagle eye-shaped headlamps, that encompass the prominent wing-shaped daytime running lights, blend with a graceful flowing silhouette that connects the new car’s muscular shoulder lines with its distinctive rear hatch area.
“We carried forward the work we began with Insignia,” says Mark Adams, Vice President Design GM Europe. “This time we’ve given our design language a fresh expression for the compact class segment. Think of it as if the Insignia and Astra are members of a family. You can recognize the same gene pool, yet each car has its own personality and character.”
The raked A-pillars flow into a diving bonnet-line, leading to narrow headlamp units, housing lights mounted on a dark inner surface, which add depth and a three-dimensional quality. The signature wing graphic on the daylight running lights sits inside sharp, eagle-eye headlamps.
The front indicator lights are now located separately in the front bumper recesses and are accented with chrome, while the neatly shaped repeater units are set into the upper front wings.
New body design sees reappearance of the ‘Blade’
A crisply-executed soft shoulder line runs along the side of the body into the sculpted rear light units. Above these, the car’s windows on most models are framed by a matt chrome surround, unique in the compact class.
Pressed into the side panel just ahead of the rear wheels is the unmistakable blade motif, echoing the distinctive design cue in the front doors of the Insignia. On the new Astra, though, the blade swings upward in a rearward movement, providing the car with its own individual identity.
In profile, the car’s svelte proportions are accentuated by the triangular shape of the rear side window, the falling roof, the wraparound rear screen and the upward direction of the blade feature.
Coupe styling with hatchback functionality
The new Astra’s side view hints at a sleek, almost coupé-like look, which belies the Astra’s generous passenger accommodation, suitable for five adults.
Viewed from behind, the shoulder line extends along the side of the body into the sculpted rear lights in one, continuous flow. Designers achieved the muscular rear proportions by creating strong rear body shoulders, combined with a wraparound C-panel and tapered rear window.
The tail light units are set apart to accentuate the width of the vehicle’s stance, and viewed at night, their double wing graphic creates an instantly recognisable appearance. This is enhanced by an upper rear spoiler, which also serves to improve the car’s aerodynamics.
3. INTERIOR DESIGN
- Clever packaging offers more occupant comfort and space
- Distinctive exterior design cues echoed in cabin
- Tactile feel throughout cabin enhanced by extensive use of premium materials
Echoing the flowing forms of its bodywork, the new Astra’s interior marks a major shift towards premium design and quality in the UK’s compact sector, and continues Vauxhall’s design evolution which started five years ago with the current Astra, followed by a further step-change last year with the launch of the Insignia.
The Astra’s interior employs the recurring wing and blade motifs that were first introduced in the Insignia and are now used in a fresh and innovative way. The blade theme is expressed in details like the gooseneck shape of the door grab handles and the trim for the gearshift moulding and steering wheel.
As you look at the Astra’s wraparound instrument panel, which embraces both front seat occupants, the wing design is immediately visible as it arcs across the cabin into the door-top mouldings. The dashboard has a black, grained finish with a subtly different texture to other mouldings in the cabin.
Ambient lighting enhances the quality feel of the cabin, with lighting points framing the gearbox surround, and providing illumination from above the centre console and within the doorhandle recesses, depending on trim level.
The feeling of cabin space and depth is illustrated by a centre panel mounted at a shallow 30-degree angle, which sweeps down from the top of the instrument panel to the centre console, creating a flowing surface that incorporates the gearshift. Like the Insignia, the Astra’s main clocks and gauges are ringed with chrome, with the speedometer and tachometer pods angled inwards towards the driver.
Special emphasis has gone into the design and engineering of the Astra’s seats, which now have industry-leading levels of adjustment. Their height can be raised by up to 65mm, while their fore and aft range extends to 280mm, allowing all drivers and passengers to find their ideal seating position. In addition, the Ergonomic Sports Seats (standard in all Elite models) have improved tilt adjustment (driver’s seat only), four-way power lumbar support, superior side support and supporting foam pads.
Storage and packaging
‘So do people actually put gloves in their gloveboxes?’
Using feedback from a customer survey, the interior team first compiled a list of the 20 most common items stored in cars: pens, coins, a flashlight, a road atlas, a parking disc, sunglasses, a wallet, paper tissues, a mobile phone, CDs, sweets, cups, magazines, newspapers, fruit, a first aid kit, a jacket, a 1.5/1.0/0.5-litre drinks bottle. And, of course, gloves.
Next, they noted where owners wanted to keep the items and looked for practical solutions. They found that car companies tended to focus on storage size alone, and that led to irritating problems, such as CDs being stored in the centre console, preventing the arm rest from being fully dropped down.
Max Kuncl, the team’s Performance Integration Manager likened the challenge to a puzzle: “It was important for the team not only to find places for the items to fit, but for the new Astra’s interior to still look great, and maintain high quality standards throughout the cabin.”
This painstaking attention to detail has resulted in a variety of simple, but effective storage solutions. A hard-shelled sunglass case has been inserted above the door opening on the driver’s side; coin slots and pen holders are moulded into the inside edge of the glove box lid; and the glove box itself has two removable compartments, while a second mini-glove box has been added just below the light switch.
Further storage innovation appears in the centre console, which can accommodate nine CD cases, as well as having a small storage area and an insert for two cup holders. There’s also the option of an under-seat drawer beneath the passenger seat which is big enough to hold a pair of shoes. Rear passengers also benefit, with a 12-volt connection available for MP3 players, in addition to space for drinks bottles.
The new Astra’s boot also came under close scrutiny. A recess was created in the side of the boot to accept either a first aid kit or warning triangle, while a patented FlexFloor was devised to offer further under-floor storage, while the floor itself can be fixed at different heights.
And those gloves? According to the survey, most owners don’t keep them in the glovebox at all. They usually get thrown in the door’s side pocket, next to the ice scraper.
Materials and quality
“Our goal was to make the perceptual quality in the interior of the next generation Astra as great as that of the Vauxhall Insignia,” says Peter Hasselbach, in charge of Design Appearance Quality. “This is in line with Vauxhall’s mission to bring innovations and quality to the compact class.”
The quality of the materials used in the new Astra can be seen in areas like the grained surfaces, the textured panels, the chrome trim elements and the feel and operation of the buttons and switches. In addition, all the Astra’s main surfaces are textured with upscale materials and top grains to give a strong, premium feel.
- Downsized petrol engines and ultra-efficient diesels with power range from 87-180PS
- Significant reduction in emissions and fuel consumption over current Astra engines
- New 1.4-litre Turbo engine promises strong performance with meagre running costs
- ecoFLEX model to join range next year with 109g/km combined emissions
Boasting a nine-engine lineup, the new Astra range will be on average 13.3 per cent cleaner and more economical than that of its predecessor, without denting the performance of any specific models.
Downsizing has been key to achieving lower emissions and fuel consumption, while a clear focus on high specific outputs and low-end torque values have ensured that strong performance is retained across the range.
The new 1.4-litre Turbo is a perfect example of this philosophy, producing 140PS and 139g/km combined C02 emissions, compared with the outgoing 1.8-litre engine, which produces the same power but with an extra 33g/km.
Sitting below the 1.4 Turbo in the petrol engine range are two normally aspirated 1.4-litre units producing 87 and 100PS respectively. Complementing these engines are two 1.6s: an un-blown unit with 115PS and a turbocharged version with 180PS.
The CDTi diesel line-up includes one 1.3 CDTi motor, two 1.7-litre engines and one 2.0-litre unit, all of which feature common rail with multiple fuel injection and are equipped with particulate filters (DPFs). These range in power from 95PS for the 1.3 CDTi to 160PS for the 2.0 CDTi.
All Astra engines meet Euro 5 emissions standards and each of the four-cylinder units is mounted transversely and features an aluminium cylinder head, with dual overhead camshafts operating four valves per cylinder.
Cast iron blocks have been used across the range for strength and reduced noise resonance, with a hollow-frame design for minimized weight. A die-cast, structural aluminium oil pan adds further stiffness and noise suppression.
Continuously variable valve timing, for both inlet and exhaust sides, is adopted on all engines, except the 1.6 Turbo. The camshafts have hydraulically operated vane-type phasers which vary the angle of each camshaft relative to the crankshaft by up to 60 degrees on the inlet, and 45 degrees on the exhaust side.
Cam phasing allows the engine control module to adjust the timing of the valve opening and closing according to varying conditions, such as engine speed and load. The many benefits include a broader spread of torque, higher maximum power and improved fuel consumption. Cam phasing is also an effective tool for controlling exhaust emissions, managing valve overlap at optimum levels to eliminate the need for a separate exhaust gas recirculation (EGR) unit.
*Final figure to be confirmed
PETROL ENGINES IN DETAIL
1.4-litre (87 & 100PS versions)
The entry-level1.4-litre, naturally-aspirated engine, with a specific power output of 71.4PS per litre (100PS unit), has excellent fuel economy and returns a combined 51.4mpg.
The camshafts are chain-driven for maintenance-free operation and feature automatic hydraulic adjustment. Further refinements include the use of hollow camshafts, for reduced weight and lower reciprocating mass, and a flywheel with a torsional vibration damper for improved running refinement. The fuel injection system also features port deactivation under part load for improved exhaust gas recirculation, giving lower emissions and improved fuel consumption.
Maximum power of either 87PS or 100PS is generated at 5600rpm or 6,000rpm with peak torque of 130Nm available at 4000rpm.
Developing 115PS at 6,000rpm, the normally-aspirated 1.6-litre has an even higher specific power output (72.5PS per litre) than its 1.4-litre, naturally-aspirated cousin. Maximum torque of 155Nm is generated at 4,000rpm, with more than 90 per cent of this value available from 3,000rpm.
Fitted with this engine, the Astra will achieve a 0-60mph time of 10.9 seconds and a combined fuel consumption of 44.8mpg – only 8 per cent more than the 1.4-litre (100hp) engine.
A two-stage variable intake manifold is fitted, and for increased torque at engine speeds below about 4,000rpm, the fuel/air intake charge passes through 620mm long inlet tracts. Above 4,000rpm, the engine management system transmits a signal to channel the air along shorter 288mm tracts, which has the effect of increasing top-end engine power.
The engine’s cylinder barrels are laser-etched for an extremely smooth finish, giving minimal piston friction and wear characteristics, while also benefiting oil and fuel consumption. Under-skirt piston oil cooling also features.
Strong performance and flexibility are the core strengths of this new-to-range engine, which produces 140PS. Torque generation is even more impressive, with 200Nm available from just 1,850rpm to 4,900rpm, translating to a 0-60mph acceleration time of 9.0 seconds.
The water-cooled turbocharger, spinning at up to 200,000 rpm, is integrated into the exhaust manifold, close to the engine, for a fast throttle response. Air-to-air intercooling increases the intake charge density.
The adoption of a steel crankshaft with reinforced pistons and con-rods allows the use of a relatively high 9.5: 1 compression ratio, despite higher stresses and loads. Under-skirt piston oil cooling jets and exhaust valves filled with sodium are further measures to ensure durability under higher internal temperatures.
The most powerful engine in the Astra’s line-up produces 180PS and achieves a specific output of just over 100PS per litre. Available in both SE and sport chassis-equipped SRi models, the 1.6 Turbo is the most powerful series production engine in its displacement class.
The 1.6 Turbo’s high power is matched by an impressively wide plateau of torque, with 230Nm available from 2,200rpm to 5,400rpm. With this engine, the new Astra can accelerate from 0-60mph in 7.9 seconds, and from 50-70mph in fifth gear in just 8.4 seconds.
In common with the 1.6 naturally-aspirated engine, the cylinder barrels are laser-etched for minimal piston friction. To withstand higher operating temperatures, the exhaust valves are filled with sodium and under-skirt piston cooling with oil jets is used. A map-based thermostat control raises the coolant temperature at low engine speeds, or under light loads, to help reduce internal lubricant friction and improve fuel consumption.
DIESEL ENGINES IN DETAIL
All Astra diesel engines are fitted with:
- 16-valve, dual overhead camshafts
- A weight-saving aluminum cylinder head
- Threaded intake ports for exceptional ‘swirl’ and burn characteristics
- Oil jet cooled pistons
- A dual-mass flywheel and a maintenance-free exhaust particulate filter.
The main technical features include:
Common Rail, Multiple Fuel Injection
Operating at high pressures up to 1,800 bar, this sophisticated fuel delivery system ensures extremely fine atomisation in the combustion chamber and enables up to five injection pulses per cycle to extract as much energy as possible from a given amount of fuel. The result is exceptionally low fuel consumption and exhaust emissions, as well as reduced engine noise. Multiple injection helps iron out the strong vibrations associated with compression ignition. For example, a pre-injection during the warm-up period reduces cold-start ‘knock’ to a barely perceptible level.
Variable Geometry Turbocharger (VGT)
The pitch of the vanes on the turbine wheel is continuously varied according to engine load and speed, giving an excellent throttle response, particularly during pick up from low speeds.
Improved Exhaust Gas Recirculation (EGR)
The electronically-controlled EGR system has an additional cooling function. Electro-pneumatically operated bypass flaps, controlled by the engine management system, ensure that the exhaust gas reaches a temperature suitable for combustion on its way back into the cylinder. This contributes to increased power, as well as reduced emissions.
The diesel line-up comprises:
The 1.3 CDTi delivers 95PS with a maximum power of 190NM at 1750rpm, emitting just 109g/km of CO2.
Available in two states of tune, providing either 110PS and 260Nm of torque, or 125PS and 280Nm. Combined cycle fuel consumption for both is 60.1mpg.
The 2.0 CDTi packs 160PS with an exceptionally strong 350Nm of torque from just 1,750rpm. This helps it achieve a 0-60mph time of just 8.5 seconds and 50-70mph in 6.4 seconds, together with a combined fuel consumption of just 57.6mpg.
Six-speed manual gearboxes, offering a wide spread of ratios and a tall, fuel-saving top gear, are standard fit across the entire range, with the exception of the naturally-aspirated 1.4/1.6-litre engines, all of which have five-speed gearboxes (for optimum fuel economy, these two-shaft units are fitted in preference to a six-speed, three-shaft gearbox). All gearboxes include triple cone synchronization on first and second gears for easy engagement, while the six-speed units also have a synchronized reverse gear.
New Auto for new Astra
An all-new, GM Hydra-Matic six-speed automatic transmission is offered with all petrol engines, except the naturally-aspirated 1.4-litre and 1.6-litre Turbo unit, which are manual only.
Instead of the new auto transmission being ‘folded’ around the end of a transversely-mounted engine, the gear sets are now on the same axis as the engine crankshaft centreline, which makes the entire powertrain unit much shorter fore-to-aft. This ‘on-axis’ design provides more compact packaging, allowing enhanced crumple zone performance, increased interior space, and a lower bonnet line than possible with a conventional off-axis design. Shifts are accomplished by applying and disengaging clutches simultaneously, which provides increased functionality and a more direct feel for the driver compared to ‘freewheeling’ gear change mechanisms.
On the road, a wide selection of shift patterns is adapted to the style and habits of the driver, anticipating when maximum acceleration or maximum efficiency is required. The electronic control will also adapt to the prevailing road conditions, reducing gear shifting when climbing or descending and using engine braking assistance during down changes.
ActiveSelect allows the driver the option of sequential gear selection via the shift lever. The driver also benefits from a “neutral” gear disengagement at idle, which reduces vibration and contributes to improved fuel consumption.
Hydraulically-damped mountings for improved NVH performance
All powertrains are bolted in position via hydraulically-damped mountings that minimize vibration through the body structure. Adaptor plates enable the same four fixing points to be used for all applications, two on the front sub-frame and one on each longitudinal beam.
The fuel supply system uses an electric pump and filter mounted in the 56-litre fuel tank, which is located low under the rear seat for optimal weight distribution and crash impact protection.
5. DRIVING DYNAMICS
- New chassis with longer wheelbase and wider tracks
- Watt’s link rear suspension combines superb handling with clever packaging
- FlexRide adaptive suspension offers drivers choice of dynamic settings
- UK-specific steering settings tuned and developed on British roads
The new Astra will not only feature a longer wheelbase and wider tracks for improved stability and ride comfort, but also a rear suspension system combining a compound crank with a Watt’s link – the first of its type in the world - that is set to offer drivers class-leading handling and ride comfort.
The Astra’s front and rear tracks have been increased by 56mm and 70mm respectively, while its wheelbase has been increased by 71mm, the cumulative effect being improved handling and ride quality, as well as more space and comfort for occupants.
Illustrating Vauxhall’s commitment to developing its cars specifically for British roads and drivers, the new Astra has bespoke steering UK settings developed in conjunction with the Vauxhall Engineering Centre, based at GM’s Millbrook Proving Ground in Bedfordshire.
And continuing Vauxhall’s trend for innovation, its engineers have combined the size, weight and efficiency of its own patented compound crank rear axle layout with a cleverly positioned Watt’s link, which supports lateral forces during cornering.
The FlexRide adaptive damping system, first seen in the European Car of the Year-winning Insignia and rare in the compact class, adjusts the suspension character automatically depending on drivers’ needs, while also offering three programmable damper settings.
Enhancing this sophisticated system is an increase in the Astra’s torsional body stiffness of 43 per cent, and of 10 per cent in bending stiffness, compared with the previous Astra, improving the car’s handling and ride quality, as well as making a significant reduction in noise, vibration and harshness (NVH).
Advanced front suspension design and clever Watt’s link at rear for superb dynamics
The Astra’s new suspension layout combines MacPherson strut front suspension with a clever, newly developed compound crank rear axle with a Watt’s link.
Front suspension is by MacPherson strut, with de-coupled top mountings that separate the paths of spring and damper loadings. To reduce unsprung weight and improve weight distribution, the combined strut carrier and the lower control arm are made from aluminium and the anti-roll bar is formed from hollow-section steel.
For optimum stability, the L-shaped control arm is attached through two bushings to the front sub-frame. The suspension geometry, and the tuning of the bushes, is designed to provide both lateral stiffness and longitudinal compliance for excellent handling and good ride comfort. The rearmost bushing of the L-arm is also hydraulically damped for excellent road isolation.
The Astra’s unique compound crank/Watt’s link rear suspension system has many advantages over a multi-link design, including improved packaging, greater wheel camber stiffness and less lower suspension friction. It also creates less camber loss due to body roll, while the Watt’s link ensures that lateral stability is maintained.
The torsion beam of the patented compound crank axle is attached between the trailing links, about half way between the axle bush and the rear wheel. The open, U-shaped profile between the attachment points has now been lengthened and the wall thickness generally increased to provide more roll stiffness. In addition, beams with different wall thicknesses are fitted to give the required roll-steer characteristics.
The Watt’s link is carried on a small cross-member attached to the underside of the car, just behind the rear wheel centre line. It comprises a short, pivoting centre link with a ball joint at each end, to which the lateral links from the wheels are bolted.
In a straight line, the set up ensures excellent stability, but during cornering it minimizes lateral deflection in the same way a modern multi-link system would do. Vauxhall’s engineers estimate that the new linkage absorbs around 80 per cent of all lateral loadings on the rear suspension. In addition, the Watt’s link reduces axle bush loads to allow softer bushings, which further isolate occupants from road noise and vibration.
Bespoke UK steering settings to cater for Britain’s unique road infrastructure
Right from the start of the Astra’s development, Vauxhall’s UK engineering arm recognized that the car needed to fulfill the very specific needs of British drivers travelling on the kind of road surfaces that are not replicated anywhere else in Europe.
Connection, Assistance, Responsiveness, Isolation, and Smoothness were cited as the key fundamentals in the Astra’s steering DNA, and after exhaustive testing on the notoriously demanding roads around GM’s Millbrook Proving Ground in Bedfordshire, Vauxhall has produced a system which provides acceptable assistance levels for a broad spectrum of drivers, while ensuring that the driver feels connected with the road at all times.
The Astra uses a rack and pinion steering system with speed sensitive assistance. But in order to provide drivers with more steering feedback, the system’s electric motor is mounted directly on the steering rack, as opposed to the base of the steering column.
The key benefits of using an electric power steering (EPS) are well known. At low speeds, the level of power assistance is increased to minimize steering effort. At higher speeds, assistance is automatically reduced to ensure a high degree of steering feel for the driver. The second important benefit is that because it does not require an energy consuming pump, and responds directly to the amount of power needed at any speeds, fuel consumption is also reduced.