With Holden's engineering team receiving constant praise for its work on Commodore, Cruze, Astra hatch and Spark, the team was keen to ensure the Cruze sedan replacement would fit the bill for local buyers.
Last year we had the chance to join Holden's engineering team during a local development drive of the new Holden Astra sedan (which is known as the Cruze sedan in the North American market) in 65 per cent prototype form.
Known as Integration Vehicles (IVs), the 65 per cent prototypes represent very early forms of the Astra sedan program. The interiors of the cars still have soft unfinished plastics, while the body contains lights that are not representative of the final product and drivetrains that are still being worked on.
It may seem strange Holden would drive these cars around decked out in camouflage, but while we're only talking about the cars today, the cars have been in the country for the past 18 months. At the time they landed in Australia the vehicle had yet to be launched in any other market, so secrecy was key.
It also gave Holden's engineering team more than enough time to start developing the chassis to suit Australia's unique conditions. We were also fortunate enough to drive the North American Cruze sedan in Nashville earlier this year, so we have a reference point for the work Holden has done.
Sedans still represent a large chunk of the small car segment. While they are outsold by hatches, Holden wanted to focus on the Astra sedan as a value proposition. While pricing is yet to be announced for Australia, our understanding is that it will sit beneath each equivalent Astra hatch model.
The Astra sedan shares the same D2 architecture as the Astra hatch, but aims to offer a slightly less sporty drive experience that takes the edge off the ride, but still remains enjoyable to drive. It's over 120kg lighter than its D1 architecture predecessor and features an impressive .295 coefficient of drag (Cd), meaning it's able to carve through the air with minimum resistance.
Under the bonnet of the entire range will be a 1.4-litre turbocharged four-cylinder petrol engine that produces 110kW of power and 245Nm of torque (when mated to a six-speed manual gearbox) and 240Nm of torque (when mated to a six-speed automatic gearbox). While the gearbox calibration has been co-developed with the global General Motors world, the suspension, steering and chassis controls are unique to Australia.
A torsion beam rear axle supports the entire Astra sedan range, despite a more sophisticated Z-link torsion beam rear suspension system being available on some North American Cruze sedan variants.
If you're not familiar with torsion beam rear suspension, it helps save money for the manufacturer and also saves weight. While in the past it has formed the basis for poorer handling characteristics, modern versions of torsion beam setups have been tuned to offer a better balance between comfort and sportiness.
An electrically assisted steering rack is standard across the range but benefits from a complete redesign for the Australian market. According to Holden, the use of electrically assisted steering has given Holden the ability to tune the steering to an nth degree and live while in the seat.
Previously, hydraulic systems would need to be changed progressively to achieve perfect steering feel. Whereas these days it's all done electronically and can be linked to speed, so that when speed increases, steering feel becomes weightier and at parking speeds it can be easier to turn to help with parking.
Finally, Holden's input on chassis controls has taken the vehicle's electronic controls to a new level. A torque vectoring program has been enabled across the range to improve handling during tight cornering and at higher speeds. While you're never likely to notice it working, the extra control and feel behind the wheel helps reduce wheel spin during cornering and offers the driver extra control.
A unique tune for gravel road driving has also been implemented to ensure buyers who drive on gravel roads aren't left in the lurch with tunes that cut in too hard and don't offer progressive intervention. Holden has also enabled and calibrated trailer sway control for any buyers wanting to tow with their Astra sedan.
Our drive program included a mix of highway driving, country roads and a host of surfaces at Holden's top-secret Lang Lang proving ground, where we had a chance to really stretch the car's legs.
On the open road we were most surprised with the smoothness of the ride at highway speeds. While it's slightly firmer than the North American tune, it offers compliance and excellent bump absorption. It's especially good when it's hit with continuous undulations which would tend to unsettle the North American chassis tune.
That translates to a sporty drive when thrown at corners. As a reference we had an Astra hatch in the drive program and while it highlighted a sportier drive, the Astra sedan still managed to hold its own.
That was partly thanks to the very eager 1.4-litre turbocharged petrol engine. It's willing to kick down and rev out to redline on command and can safety be called upon out of a corner without a risk of excessive wheel spin. Most drivers are never likely to drive the car at any great pace through corners, but it's reassuring to know it's happy regardless of road conditions.
At the helm it doesn't behave or feel like a sedan. It still has the characteristics of the Astra hatch, but with softer edges. It's easier to steer and doesn't offer as much steering feel, but buyers wanting a car in this segment will enjoy how progressive and easy to drive it is.
Brake pedal feel is good — but it could be a little more responsive. We're obviously aware of the fact these are 65 per cent prototypes, so they're not representative of the final product, but its something we understand Holden is looking at.
Part of our drive included a set of flying laps of Holden's hillclimb. The unique circuit includes a couple of steep hills, some sweeping bends, a hairpin and some slower technical corners, padded out by a heap of trees — meaning there's little room for error.
With an Astra R hatch in the mix for reference, we set off to see just how dynamic the Astra sedan is. For a small four-door sedan, this thing has some real cornering ability. The torsion beam rear suspension setup handles mid-corner bumps really well — this is where a torsion beam falls down due to the rigid connection between both sides of the car. Normally a hit on one side translates to the other, but in this instance it remained well behaved.
During a steep constant incline we found the Astra sedan was pulling away from the hatch. Again, it could be due to a non-final engine tune, but we were really surprised with how much pull the car had through the rev range. It uses that full complement of 240Nm of torque eagerly.
There was a fair bit of noise intrusion into the cabin under high throttle loads, but this is likely due to a lack of insulation between the engine and cabin, which will be rectified with the final product.
In comparison to the Chevrolet Cruze sedan, we found the Astra sedan to offer a sportier edge, but not going as far as the Astra hatch. It sits in a pleasant middle ground between soft and sporty.
In terms of specification, we understand the Astra sedan will launch with three models — an entry-, mid- and upper-specification with pricing to sit beneath the equivalent Astra hatch.
Globally the D2 architecture sedan isn't available with autonomous emergency braking (AEB) and while the car is expected to come with reverse parking sensors and a reverse-view camera, it's disappointing Holden will be left behind by its competitors on the safety front as soon as the car launches.
Six airbags will be standard across the range, along with two ISOFIX points in the second row with three seat anchorage points.