► All-new Vauxhall Astra driven in prototype form
► Clean-sheet design, much lighter than current car
► On sale late 2015, early signs are promising
For a moment I had to pinch myself that I was in Bedfordshire driving this year’s all-new Vauxhall Astra prototype, rather than sampling the latest Lotus in Norfolk. Because all the talk of the seventh-generation Astra, in showrooms in late 2015, echoes Lotus founder Colin Chapman's ethos: performance out of light weight.
2015 Vauxhall Astra: what’s new?
The new Astra is a clean-sheet design, unlike the so-so Corsa with its carryover platform. And that means the engineers could optimise vehicle dimensions and materials to pare back weight compared with the previous D1 generation. 'That car has one weakness: it's quite heavy,' says the Astra's vehicle line director, Horst Bormann, a master of Germanic understatement.
The new D2 generation is not, far from it. It slices a whopping 130kg on average out of its predecessor's mass, by stepping into a virtuous circle of weight saving. Blending steels of different thicknesses and a smattering of exotic materials like magnesium has reduced the body in white by 21%. Reduced mass means engines can be downsized without compromising performance, the suspension has adopted more aluminium, and wheels and brakes shrunk in turn.
In addition, the new Astra range has been simplified to hatch and estate, and not having to bolster the platform for heavier convertible and Zafira MPV variants has also helped the efficiency drive.
What about engines?
CAR drove a 1.4-litre petrol D2 prototype back to back with today's D1 car running the same engine block. This Ecotec direct injection turbo engine has been heavily revised: it now musters 143bhp and 173lb ft of torque, fractionally up on today’s outputs. But the differences in performance are obvious. The new Astra accelerates far more vigorously. Mid-range punch in fourth gear is strong, ideal for overtaking. The engine sounds far smoother than in today's car, amplified by the fact you don't need to work it so hard. And braking performance is utterly transformed, biting hard and slowing much more eagerly, and with far more responsive pedal feel.
The Astra has also shrunk in size, with a reduced front overhang, shorter wheelbase and overall length trimmed to 4370mm. But that's not at the expense of cockpit space: rear legroom has increased by 34mm. A 6' passenger can comfortably sit behind an equally tall driver without knees cuffing the seat back: legroom doesn't feel far off a car from the class above. And headroom is equally generous, partly aided by the seats being set lower.
Vauxhall's benchmarks are the Ford Focus for driving dynamics, and Volkswagen's Golf for refinement. Both those cars have a multi-link rear axle, credited with improving ride and handling. The Astra carries over its Watts link design: Vauxhall's engineers are confident they’ve tuned it to match rivals' comfort, while also offering the stiffness required for decent dynamics. It’s lighter than a multi-link, and its compact design impinges less on boot space.
What does all that weight saving mean for the handling?
The ride is taut and body control is good. GM tests prototypes on potholed UK roads, and when the going gets tough and the ride gets busy, the tautness is not jarring and the body settles quickly after bumps. Mechanical and road noise are well suppressed, and the whistle of wind is reduced compared with today’s car. Accelerating hard in fast, sweeping corners, the nose tucks in obediently and refuses to wash wide. And roll is well controlled, despite the tyres quivering under the lateral loads.
The steering feels nicely weighted, unaffected by intrusive self-centring or leaden heaviness. There's a Sport button, which changes the throttle, engine and steering maps. The six-speed manual gearbox linkage has been revised but it's still not up there with Japan's tactile best: the gate feels a bit wide, but it is pretty accurate. All in all, the Astra feels promisingly agile.
Any other benefits?
Aside from the 1.4 turbo, there'll be a 1.6-litre common rail diesel, with 130bhp and 236lb ft torque. But the big news is that the lithe new Astra can run three-cylinder engines, which would have run out of puff pushing its portly forebear. These are linked to a five-speed manual. A six-speed automatic transmission will be optional on the four-cylinder engines: don't hold your breath for a dual-clutch 'box.
Fuel economy will be 'significantly better than before,' says Bormann. Vauxhall isn't revealing figures at this prototype stage, but you can expect a double digit improvement.
This prototype drive reveals the promising new Astra delivers a big improvement over today's car, naturally. The employees preparing for hatchback and estate production at the UK's Ellesmere Port plant can be optimistic. Punchier, more agile, with superior refinement and reduced fuel consumption – it's a telling demonstration of performance out of light weight.