Commodore hits a six with SIDI

22:57, Nov 10 2009
Holden commadore
ROOMY: Holden is making some interesting claims on behalf of its recently face-lifted Commodore range.

Holden's new leaner and greener Commodore is now on the market in New Zealand. ROB MAETZIG tries one out to see if the new technology really works.

The Australian manufacturer reckons the installation of new spark ignition, direct injection (SIDI) V6 engines, six-speed automatic transmissions all round and various other technology improvements are helping make the vehicles so fuel-efficient that many use less petrol than some four-cylinder cars.

For example, the base 3.0-litre Omega and Berlina models now have official fuel consumption figures of 9.3 litres per 100 kilometres, says Holden. And even the biggie versions such as the 3.6-litre, long-wheelbase Statesman claim a fuel consumption of 10.3L/100km.

Holden reckons the official fuel consumption reductions range from 9 per cent to 13 per cent, and that there is a corresponding reduction of CO2 emissions.

To underline that, recently an employee drove an Omega from Melbourne to Sydney on a single tank of fuel, a distance of close to 900km.

All those are impressive numbers, and they beg an obvious question: Is this economy achievable in real-life conditions?


So we decided to put a Commodore to the ultimate test. We got our hands on a 3.6-litre SV6 Sportwagon, filled it up with four blokes, their golf clubs and assorted carry bags, and took off on a return drive from New Plymouth to Rotorua to compete in the annual national news media golf tournament.

Holden claims that this vehicle boasts a 9 per cent reduction in fuel consumption, from 11.3L/100km down to 10.3L/100km.

We presumed this consumption figure would be with just one or two people on board - certainly not four adult males and their equipment, which would probably have a combined weight of as much as 500kg. So would the fully-laden SV6 Sportwagon be capable of travelling the 600km- plus distance from New Plymouth to Rotorua and back on a single tank of fuel? We loaded up the attractive bright green vehicle and set off to find out.

Now, this drive through the central North Island is a difficult one. Fuel-burning obstacles include Mt Messenger, the Awakino Gorge, Mahoenui Hill, the journey past Pureora Forest, and the windy bits alongside the Waikato River between Whakamaru and State Highway 1. There are not many areas of any real distance where a driver can truly indulge in fuel-saving techniques for any decent amount of time. So we just drove the route - we kept the big Commodore at the legal speeds at all times and made efficient use of its lovely new six-speed automatic transmission to get over all the hills and to pass slower cars and trucks.

By the time we got to Rotorua the fuel gauge was showing ever so slightly over half-full and the on-board computer was telling us that our average fuel consumption had dropped to 12.1L/100km from the 13.2L/100km it was displaying when we started off.

If the computer was accurate, this meant we would have used around 36 litres of petrol - and a Commodore's fuel tank contains 73 litres. So would we get back without having to refuel? It was going to have to be a careful drive home.

The fuel gauge was showing below quarter-full and the computer was telling us our remaining range was 130km, when our party stopped at Mokau, 86km from New Plymouth, for the traditional springtime feed of whitebait fritters.

Then somewhere south of Mt Messenger, maybe 50km from our destination, the computer suddenly began flashing a Low Fuel warning sign.

What did this mean? What was our remaining range? So we consulted the owner's handbook, which advised us that when the Low Fuel sign lights up, it means the Commodore is low on fuel and needs to be replenished.

And it further advised us that when the computer display begins flashing Very Low Fuel, it means the car is very low on fuel and urgently needs gas.

Thanks for the help Holden, we thought, and carried on.

On the outskirts of New Plymouth I chickened out.

The computer had not changed from Low Fuel to Very Low Fuel, which probably meant there was still a fair amount of petrol in the tank, but I still had to drop off my mates and then get home.

So we hauled into the nearest service station and gave the Commodore a much-needed drink.

But importantly, we had made it - we had made the complete trip on a single tank of fuel. And our average fuel consumption had continued to improve, with the computer showing that it had fallen further to 11.8L/100km.

I felt that was rather good considering the weight the SV6 Sportwagon was carrying. As a result I quite believe Holden's statement that with a more reasonable load, the model would be quite capable of achieving the claimed 10.3L/100km, probably considerably better.

My golfing buddies thought the motoring experience aboard the big Holden was pretty good too - they must have, because those in the back seat slept most of the way home!

But that is the whole point of large cars such as the Holden Commodore. Intentionally of such a size that they can fit three adult bums across the back seat (two is much more comfortable though), they offer excellent space front and rear, and they boast a nicely powerful drive.

The whole point of the upgrade is to deal to the one problem traditionally associated with big cars - they use too much fuel.

Enter the SIDI technology.

Spark Ignition Direct Ignition works by injecting fuel directly into the engine's combustion chambers, which allows higher compression ratios and more precise fuel distribution. This in turn improves engine performance and efficiency, because less fuel is required to produce equivalent kilowatts of power.

The engines also have lower idling speeds (they are tuned to idle at just 550rpm), they have new high-efficiency alternators, regulated voltage control which allows greater use of the battery and improved fuel cut-off during deceleration.

The 3.6-litre V6 powering the SV6 Sportwagon now offers 210 kilowatts of power, while the torque is 350 newton metres. That is easily sufficient to transport a wagon-load of blokes and their golfing equipment in a relaxed fashion.

And the new six- speed automatic transmission is a beauty. Known as 6L50, it is a derivative of the 6L80 auto fitted into V8-powered Commodores in 2006. It allows reduced engine load at cruising speeds, and a lower engine speed which improves fuel economy while reducing engine wear and noise.

There are also a heap of other new fuel efficiency features aboard this latest Commodore. Tyres are now low-friction types that weigh an average of 2kg less than conventional tyres, and to help take best advantage of that the suspension has been retuned.

Not that you really notice any of that. With this new Holden you simply drive and usually the only time you become aware of the fuel consumption is when you notice the car needs refuelling.

These days that happens a little less often - and that is the best feature of this facelifted Commodore.


POWER PLANT: 3.6-litre spark  ignition direct injection DOHC V6  petrol engine, 210kW at  6400rpm, 350 Nm at 2900rpm.

RUNNING GEAR: Rear-wheel  drive. Six-speed automatic  transmission with manual over- ride, multi-link Linear Control  suspension system. Electronic  stability control.  HOW BIG: Length 4897mm,  width 1899mm, height 1476mm,  wheelbase 2915mm.

HOW MUCH: $56,290.

WHAT'S GOOD: Fuel  consumption has been lowered,  but power and torque is better,  too. Love the six-speed auto.

WHAT'S NOT: New low-friction  tyres may impact a little on road  grip.

OUR VERDICT: Holden is to be  congratulated for addressing the  big issue of fuel consumption.  While this vehicle is not diesel- frugal, the economy we achieved  fully-laden was very good.

OUR VERDICT: Holden is to be  congratulated for addressing the  big issue of fuel consumption.  While this vehicle is not diesel- frugal, the economy we achieved  fully-laden was very good.

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