New heart under lion's skin

At the heart of the new model range is the all-new 3.6-litre Alloytech V6 being built at Holden's $400million Global V6 facility in Port Melbourne.

Although the engine was largely developed in the US as General Motors' multi-use global powerplant, Holden engineers were involved in the design from day one. While the engine is suitable for both front- and rear-wheel-drive applications, it is at Holden that the engine's rear-wheel ones shine.

"They (the engines) are the culmination of years of intensive development by Holden engineers, who are quite rightly recognised within the GM organisation as world-class in rear-wheel-drive powertrain application," says Holden chairman and managing director Denny Mooney.

"The six-cylinder engine has been the heartbeat of the Holden brand for more than 50 years and the launch of a new-generation Holden six has always been the catalyst for change.

"Apart from the direct benefits of increased power and mid-range torque responsiveness, Alloytech models also bring new electronic systems that offer even more confidence-inspiring driver control and greater safety."

The new six will be utilised by Holden in two iterations – a base 175kW model with 320Nm of torque for Executive, Acclaim and Berlina models, and a 190kW, 340Nm version for the SV6, Calais and long-wheelbase Statesman.

Both engines are distinguished by the torque spread, 90per cent of which is available between 1600rpm and 5500rpm.

As part of the extensive engineering upgrade – described by program manager Kevin Yardley as "the most substantial since the VT in 1997" – Holden spent $189million directly on development, drove 1.6million testing kilometres and had 46 vehicles driving public roads for real-world validations.

Coupled to the new engines are a range of new and revised transmissions, highlighted by the 5L40 five-speed auto, which has been coupled to the 190 engine.

The same powertrain is already in use in the Cadillac CTS and STS and will be utilised across the Commodore range in the 2006 VE car. The 5L40 also features "Active Select", a variant of the ever-growing fascination with steering wheel-mounted shift paddles.

The paddles do not have an auto-action function where they are selected simply by use but must be switched on and off by a centre console-mounted button.

The SV6 offers the option of a new six-speed manual. The base Alloytech retains the ageing 4L60 four-speed box, which has been refreshed with a new torque converter and advances to the control module, software and calibration to best utilise the engine's torque characteristics.

For what Holden says is the first time on an Australian-made car, a range of the Alloytech 190 specified models will feature an Electronic Stability Program incorporating traction control, anti-lock braking, corner control (differential) braking, brake assist and electronic brakeforce distribution.

The V8 models still utilise the 5.7-litre Gen III V8 – the 6.0-litre Gen IV is a probable starter for the VE – but there are refinements to the engine's mapping and its ability to breathe, as well as to transmissions.

The engine picks up 5kW to rate at 250kW and a similar amount of torque to lift it to 470Nm. The six-speed manual carries over from the VY but the ratios have been tweaked to provide a 3.73:1 final drive with greater launch feel and a greater ability to sustain mid-range.

Pricing increases by an average 1per cent across the range but it is very much a case of peaks and troughs with some models costing less while others remain unchanged.

Gone from the model range are the S cars, replaced by the SV6 with an Alloytech 190 engine, five-speed auto or new six-speed manual. Also dumped are the supercharger versions of the S, Calais and Statesman.

The VZ starts at $33,160 for the Executive. Holden's executive director for sales and marketing Ross McKenzie admits that while the uptake rate on the $2250 optional airconditioning would be as high as "99.9 per cent" it was decided not to include it as a standard feature.

"It is a marketing decision to allow us the room to offer no-cost option packages later (in the model life)," he says.

If there is an immediate impression from behind the wheel of the new VZ Commodores it is a subtle one. The Alloytec engines do not give an overt impression of extra power but smoothness is at a premium.

The five-speed automatic gearbox feels particularly well suited to the engines' torque delivery, with hunting for a ratio no longer an issue. In part, the effect of smooth acceleration is helped by the across-the-range use of electronic throttle control.

Noise intrusion is minimal both from road and airflow and ride quality is on a par with the outgoing model.

The first "now that's better" moment comes turning into a corner at anything better than tootling speed. The turn-in feel is definitely sharper, the wheel position more defined and feedback more lively. That feeling comes from the major front-end engineering change, which was to revise the mounting for the stabiliser bar, substituting a rubber joint with a ball joint and shortening the bar crank length by 40mm.

The stability program on the only test car driven with it – a Calais V6 – gave an impression of coarseness as the individual wheel braking for corner brake control was activated.

By contrast the traction control function was far less intrusive than has been the case previously with Holdens.

Aesthetically the changes are generally on the restrained side but significant enough for owners to acknowledge they are driving the latest model. The most overt addition is the side vents in the SS model and the larger Lion badge on the grille of the Executive, Acclaim, SV6, SV8 and SS models.

Changes to the headlight and tail-light treatment include circular rear lamps on the performance models, while all models now have a variety of the single-bar grille.

As befits the high-end long-wheelbase vehicles, Statesman and the top of range Caprice ($69,650 for the V6 and $74,390 for V8) get LED brakelights – claimed to illuminate 1000 times faster than globes – and a new interior colour treatment in muted grey and beige as well as standard leather.

Is Holden heading in the right direction? We'd like to know. Let us know in the comments below.