GM reveals Commodore's future power options

HOLDEN’S crucial new VE Commodore sedan is still two months from being launched but parent company General Motors has already shed light on some of the technology it may eventually embrace.

GM last week revealed a direct-injection version of the 3.6-litre Alloytec V6 produced by Holden, plus a V6 equipped with Active Fuel Management cylinder deactivation technology and a raft of future vehicle applications for its new range of six-speed automatic transmissions.

In a press release issued last Wednesday (May 18), the world’s largest car-maker revealed that its first petrol V6 with direct fuel-injection will be made available from 2007 in a model to be announced later this year.

GM has forecast that, globally, it will produce up to 200,000 vehicles with direct-injection by the end of 2008, and that by 2010 one in six GM vehicles sold in North America will be equipped with a direct-injection engine.

GM’s ground-breaking new petrol injection technology, which is already offered by a number of European marques and is considered the biggest leap in fuel metering technology since multi-port fuel-injection, has direct implications for future Holden Commodores.

The new 3.6-litre VVT DI is based on the same GM Powertrain-designed 60-degree DOHC V6 that’s manufactured at Port Melbourne for the likes of Saab, Alfa Romeo and Holden’s own Commodore model family, in which it also displaces 3.6 litres and is known internally as High-Feature V6 (HFV6), in export terms as Global V6 and locally as Alloytec V6.

According to GM: "It is the latest member of a growing family of GM Powertrain V6 engines developed for applications around the world, drawing on the best practices and creative expertise of GM technical centers in Australia, Germany, North America and Sweden." Like the V6 employed by VZ Commodores since August 2004, the VVT DI V6 features an aluminium engine block and cylinder-heads, forged steel crankshaft, dual overhead camshafts with four valves per cylinder, coil-on-plug ignition and electronic throttle control.

However, apart from the same "four-cam" (inlet and exhaust) continuously variable valve phasing as found on the 190kW 'Alloyec 190" V6 that powers premium Commodore variants, the direct-injection version adds a high-pressure engine-driven fuel pump, more advanced heat and pressure resistant multi-outlet fuel-injectors, a stainless steel variable-pressure fuel rail, more advanced engine control module and higher 11.3:1 compression (up from 10.2:1).

GM claims the result is a 15 per cent increase in peak power, an eight per cent improvement in maximum torque and up to three per cent better brake-specific fuel consumption – as well as 25 per cent lower cold-start hydrocarbon emissions.

Directly injected fuel has a cooling effect inside the combustion chamber and enables a higher compression ratio - both of which improve performance. Fuel consumption also reduces because less fuel is required to produce the equivalent power of a conventional port-injection combustion system.

"The 3.6-liter VVT with direct injection will be our highest specific output non-turbocharged V6 engine, as well as one of the most fuel-efficient offerings in our high-feature family," said Tim Cyrus, chief engineer for the HFV6 and Northstar V8.

"It’s the latest example of our strategy to continue to reduce emissions and improve fuel economy without sacrificing performance." The VVT DI follows GM Powertrain’s use of direct-injection for the Ecotec 2.0-litre turbo four fitted to the 2007 Saturn Sky Red Line and Pontiac Solstice GXP roadsters, while GM’s first direct-injection engine was an Ecotec 2.2-litre found in a number of European Opel models.

Holden concedes that, like turbocharging, LPG and petrol-electric hybrid technology, the VVT DI V6’s direct-injection system could bring benefits for Commodore’s V6 in the long-term – if it chose to invest engineering capital.

"The announcement on direct-injection has no immediate impact on local programs," Holden spokesman Jason Laird told GoAuto this week.

"The Global V6 was designed for flexibility to accommodate a range of leading-edge applications including spark-ignition direct-injection, turbocharging, LPG and hybrid uses.

"The introduction of those applications becomes a choice for each market and use of engineering funds." GM last week also announced its first V6 application of the Active Fuel Management cylinder deactivation system, which could also become a valuable fuel-saving asset for Commodore.

Also known as Displacement On Demand, which is expected to feature on 6.0-litre V8-powered versions of the VE Commodore, AFM allows the engine to operate on half its cylinders under light load conditions.

AFM is already available in the US in a variety of 5.3-litre V8 models and will be launched in V6 guise in the 3.9-litre 2007 Chevy Impala. GM says that by 2008 it will make 15 AFM-equipped models available and expects two million to be on the road.

GM last week also committed to offering 14 ethanol or "E85"-compatible models (totaling about 400,000 vehicles) in 2007 – up from nine this year. E85 FlexFuel vehicles run on 85 per cent ethanol and 15 per cent petrol, while full FlexFuel models can run on either, or any combination of the two.

While ethanol remains a possibility for Commodore, it’s likely Australia’s most popular car model will offer diesel power sooner.

"We are interested in exploring diesel options on a number of car lines, including Commodore," says Holden.

"There is nothing in the short term to point towards, but it is definitely in our thinking.

"We would obviously need to identify the correct powertrain to deliver the right Holden performance characteristics before introducing it in Commodore.

"Appropriate performance is a non-negotiaable - hence the Astra turbo diesels being introduced next month." GM also announced it will offer a new hybrid system that improves fuel economy by 20 per cent in the Saturn Vue Green Line, which will claim to be the least expensive hybrid SUV available when it’s launched in mid-2006.

The company’s forthcoming two-mode hybrid powertrain, co-developed with DaimlerChrysler and BMW, offers yet another alternative fuel option for Commodore as record fuel prices help force sales of Australia’s favourite model to a 12-year low.

However, unlike direct-injection, diesel, LPG, variable-displacement and even turbo technologies, hybrid power is at best a slim possibility for the next-generation VE as Holden – like Toyota with its upcoming Camry – struggles to make a business case for relatively costly petrol-electric power in a mainstream sedan.

"We're interested in hybrids and the joint-venture hybrid system offers something tangible to consider," said Mr Laird. "(But) The existing and likely near-future sales of hybrids in this country don't nearly match the (automotive publication) column centimeters dedicated to them." One thing that will appear from the launch of the VE Commodore, however, is a six-speed automatic transmission to match Falcon’s optional German-built ZF self-shifter.

GM last week revealed details of a second new Hydra-Matic six-speed auto for rear-drive applications, dubbed 6L50.

Designed for longitudinal-engined, rear and all-wheel drive vehicles with a maximum engine performance rating of 235kW/450Nm, it’s a lighter-weight version of the 6L80 slusher that’s now available in the US-market GMC Yukon Denali family, the Cadillac XLR-V, STS-V and Escalade, and the Chevrolet Corvette.

While the 6L80 will be mated to all (6.0-litre) V8-powered VE Commodore variants from launch, the 6L50 gives the option to offer Commodore V6 with a six-speed auto rather than the five-speeder that became standard in premium VZ variants.

Both 6L50 and 6L80, which is rated for engine outputs of up to 308kW/583Nm, feature a "Driver Shift Control" manual-shift mode and two overdrive gears.

The 6L50 will debut in 2007-model rear and all-wheel drive Cadillac STS sedans and the V8 SRX crossover this year.

Whether or not Holden eventually offers a six-speed auto-equipped V6 in VE Commodore, the 4L60/65 four-speed currently offered in entry-level Commodore V6s and all V8 variants will be banished.

The current Calais and SV6’s 190kW Alloytec engine is expected to become standard across the range and is likely to offer a 200kW power output. The V8, meantime, should gain 5kW to offer the full 265kW offered by the L76 in the US.

Also doomed is the current VT-based VZ Commodore’s trailing arm rear suspension, which will be replaced by a multi-link IRS like Falcon’s, although Commodore’s MacPherson spring-strut front suspension configuration is likely to stay.

Due on sale in August, just weeks before its all-new and more extensively differentiated long-wheelbase WM Statesman sibling is released, the VE Commodore sedan is expected to increase its kerb weight by at least 100kg thanks largely to extra safety equipment like side curtain airbags, bigger brakes and standard stability control, and crashworthiness - especially in terms of side impact safety.

As a result, overall length is likely to grow by about 150mm, while interior space gains should be minimal. Expect 16-inch wheels/tyres to replace the base Executive’s 15-inch items and the performance SS flagship to run on 19s.

Numerous advanced prototypes, built on Holden’s Elizabeth, SA production line, have been spotted in disguise on public roads, where its rounded roofline, heavily flared wheel-arches and rear-mounted fixed-mast aerial appear in stark contrast to the current Commodore - and are more akin to Holden’s 2004 Torana TT36 concept.

What’s coming from Holden:

Astra diesel – June 2006
Astra Turbo – June 2006
Captiva SUV – July 2006
VE Commodore sedan range – August 2006
WM Statesman sedan range – September 2006
VE Commodore utility range – late 2007
VE Commodore wagon range – early 2008