GM HOLDEN has launched the first Australian-built small car in more than 12 years, releasing detailed information on the changes wrought upon the Cruze in its transition from Korea to Adelaide manufacture.

On sale from late March, with deliveries due from mid-April, the upgraded JH-series – or ‘Series II’ - sedan is a visual makeover as well as an evolution of the highly successful JG, encompassing a fresh face, improved Euro-V emissions-meeting engines, and better performance and refinement.

Aiding the latter are new powertrain calibrations and differences in insulation, while the implementation of a solar glass windscreen benefits cabin comfort as part of a two-year, 350,000km validation and testing program conducted by Holden.

However, the big news – at least until the Holden-designed JH five-door hatchback joins the facelifted sedan on sale here in October – is the combination of a downsized turbo-petrol engine and a significant new chassis package.

It arrives in some Cruze variants in the form of a new 1.4-litre ‘iTi’ engine, Watts link rear suspension and electric power steering (EPS) set-up – a combination that cannot be ordered individually.

Cribbed from the Opel Astra J due on sale in Australia during 2012, it highlights the similarities and interchangeability of both models, since they share the same General Motors Delta II small-car architecture.

Available optionally (for $1250) on the entry-level Cruze CD and standard on the new sports-oriented SRi and sport-luxury SRi-V grades, the 1.4 iTi components aim to improve the Cruze’s dynamic capabilities – an area that has come under criticism since the JG’s launch in June 2009.

If demand exists, a CDX iTi may also be introduced.

Ending two years of sourcing from GM Korea (formerly GM DAT – Daewoo as a GM brand is now dead even in its home country as the country adopts the Chevrolet moniker there), the Cruze is said to ‘future-proof” Holden manufacturing in Australia, where small cars comprise more than 25 per cent of annual new vehicle sales.

“It’s a great place to be – making the best selling car in Australia as well as one that competes in the most popular segment,” Holden chairman and managing director Mike Devereux told GoAuto.

From launch less than 50 per cent of the JH is produced in Australia (including its roof, body sides, closures, fascias and most interior plastics and trim), with local content expected to increase in a tiered manner as more suppliers come on board over the next few years, according to a Holden spokesperson.

Holden says limited resources and tight timing prevented it from altering much visually beyond the plastics (bumpers – including different air-intakes and fog light housings), wheels and interior trim.

But the headlights now have amber flashers and a more flush-fitting beam unit for a more integrated look, while the rear bumper has a squared-off ridge for subtly improved aerodynamics. Look for a similar treatment on the 2014 VF Commodore, according to design boss Tony Stolfo.

As far as the SRi newcomers go, both are identifiable by a modified grille and air-intake, a rear lip spoiler and revised alloy wheels, while the SRi-V introduces remote keyless entry and start, satellite-navigation, a 10GB hard drive, CD/MP3 rip and store capability, DVD player and live-radio pause functionality to the Cruze for the first time.

Since the JH is built on the same Elizabeth production line as the VE Commodore Series II and its many variants, the two Holdens share many of the same paint colours, increasing the palette choice on a vehicle that is already highly regarded for its varied hues, says sales and marketing chief Philip Brook.

Holden executives will not reveal sales forecasts, but privately one company insider told GoAuto the Cruze nameplate is likely to push past the Toyota Corolla’s and Mazda3’s 40,000 annual volume barrier when the JH hatch comes on stream from late this year. In 2010, just under 29,000 Cruze CD and CDX sedans found buyers.

The company has high hopes for the 1.4 iTi. A 1398cc DOHC four-cylinder petrol unit with variable valve timing and a turbocharger that is integrated within the exhaust manifold, the Austrian-made 1.4 iTi delivers 103kW of power at 4900rpm and 200Nm of torque between 1850-4900rpm, and is paired to six-speed manual or automatic transmissions, the latter with a manual-shift mode.

It averages 6.4 litres per 100 kilometre (auto: 6.9) and 153 grams per kilometre of carbon dioxide emissions (auto: 164).

For even better fuel economy, Cruze buyers can choose the heavily revised 2.0-litre turbo-diesel engine, now with DOHC (instead of the old single-cam design).

Although power is now up nine per cent to 120kW at 3800rpm and torque jumps 12.5 per cent to 360Nm at 2000rpm, combined average fuel consumption now slips 0.1L/100km to 5.6L/100km for Diesels fitted with the improved six-speed manual gearbox, making this the most economical Australian-built car available. Sticking with the 6T45 six-speed auto means the figure remains unchanged at 6.7L/100km.

Holden expects the Diesel’s popularity to increase as fuel prices spike upwards. Currently it accounts for about 20 per cent of all Cruze sales.

Will the least-changed JH engine – the long-lived 1.8-litre Ecotec four-cylinder petrol unit – be overtaken by the 1.4 iTi in sales?

For performance it already has while minor modifications have resulted in driveability and fuel economy improvements (Holden says it placed an emphasis on testing the Cruze in Sydney traffic in order to overcome performance and refinement limitations evident on the hilly terrain), outputs remain at 104kW at 6200rpm and 176Nm at 3800rpm respectively. Among the changes is a new final drive ratio.

The standard five-speed manual version returns 7.0L/100km while the $2000 optional 6T30 (lighter and more compact than the 6T40 used in the old 1.8L) six-speed automatic gearbox helps the JH slurp slightly less unleaded petrol at 7.4L/100km (it was at 7.5).

While the 1.8L Ecotec and 2.0L Diesel engines retain the JG Cruze’s torsion beam rear suspension and hydraulic-powered rack-and-pinion steering system, the 1.4 iTi’s Watts link/EPS components aim to bring improved lateral control while cornering, according to Holden.

Said to closely emulate the benefits of a more expensive, complicated and space intrusive multi-link arrangement (as pioneered on the Ford Focus and since adopted by the VW Golf, Mazda3 and others) by minimising lateral deflection, the Watts link is carried on a small cross-member attached to the Cruze’s underbody behind the rear-wheel centre line. It comprises a short, pivoting centre link with a ball-joint at each end, to which lateral links from the wheel are bolted.

Because the Watts link is designed to lessen axle-bush loads, softer bushings can be employed, improving isolation, reducing road noise and adding a degree of suppleness to ride comfort.

Meanwhile, the EPS only draws power from the electrical system when required, cutting engine load and power drain, and thus increasing fuel efficiency. The speed-dependent system has been tuned for improved feel and reduced effort at parking velocities.

As before, all models score a five-star ANCAP crash safety rating, and include six airbags, electronic stability control (ESC), ABS brakes, electronic brake-force distribution (EBD) and collapsible pedals.

To make the Cruze in Australia, Holden accessed $149 million from the Federal Government’s discontinued Green Car Innovation Fund and another $30 million from the South Australian state government.

Prices for the volume-selling 1.8-litre petrol engine models (CD and CDX) remain the same at $20,990 and $22,990, but the new twin-cam 2.0-litre turbo-diesel now costs $500 more.