Each year Holden invites Australian journalists to compete in an annual fuel efficiency drive from Sydney to the Gold Coast. It ends as the annual Indy Car event starts and is a challenging two-day drive that weaves along the coast and through the Great Dividing Range in its bid to replicate a wide range of Australian road conditions.
In previous years, Holden has switched journalists across a cross-section of its passenger car range across six stages. This year the focus vehicle was the VE Commodore in all its derivatives.
For each stage, Holden engineers set a target fuel economy figure for each model along with a time limit for each stage. Each target was calculated within all speed limits.
Drivers had to swap into a different model at the close of each stage. A Holden representative was attached to each car to act as navigator and to ensure that the prescribed route and all rules were followed. For example, switching the engine off to coast down hills was not allowed. The engine also had to run while stationary at traffic lights or other unscheduled stops such as road works or traffic snarls.
Each driver had to weigh in with their personal luggage. Because this determined an equivalency factor across each entry, it was paramount that drivers cleared their cars quickly at the close of each stage and transferred their luggage to the next vehicle.
In past years, the penalties for exceeding the time limit allocated to each stage were quite severe. Because unscheduled delays sometimes encouraged drivers to compensate for any loss of time by breaking the speed limit, the time penalties were softened in 2006 when the primary aim was to generate realistic fuel economy figures for the new VE Commodore.
As some front runners continue to employ some severe or unrealistic driving techniques to match or beat the factory targets, CarPoint was more interested in seeing how close an average driver can get to the targets by simply driving sensibly at full highway speed limits and treating the time limits seriously.
It is significant that using this approach, CarPoint posted a highest of a fourth place and finished overall somewhere in the middle.
THE EVENT IN DETAIL
STAGE 1: SYDNEY AIRPORT TO RAYMOND TERRACE
Model: VE Calais V6 auto
Target: 7.6lt/100km
Our Figure: 7.85lt/100km
Report: Despite catching the closing stages of Sydney's peak hour, we were able to maintain a constant and smooth drive through Sydney's most congested areas. It was evident that the Calais' more sophisticated High-Output V6 and its five-speed auto (compared to the four-speed base Omega) were making all the difference under these conditions -- able to deliver the right gear, ready to pull strongly with light throttle inputs.
It was a relaxing drive that could be replicated by any alert driver and an impressive figure for what was still mostly stop-start inner city traffic and congested freeway.
Insights: Varying your departure time by just 15-20 minutes either side of the traffic peak can make all the difference to fuel economy if it reduces the number of stops. Open road lanes also allow you to maintain momentum between lights on light throttle openings and anticipate green lights without having to stop.
Knowing exactly where you are going also makes a big difference when you can position the car and adjust the speed ready for turns or changes in direction without having to brake or accelerate sharply.
STAGE 2: RAYMOND TERRACE TO WINGHAM
Model: VE SV6 manual
Target: 7.2lt/100km
Our Figure: 8.lt/100km
Report: After such a good start, we were forced to wait until the end of the designated lunch break before our next vehicle turned up. As a result, the hungry navigator assigned to this SV6 had to catch up on lunch during Stage 2 so we missed a vital turn-off on an unbroken freeway stretch. This added an extra 6km to the stage before we could rejoin the route.
Although this didn't impact on average fuel consumption, it made the time target tight. Both delays then dropped us into several 40km/h school zones further adding to time pressures.
This was an undulating and winding country route punctuated by small towns on typical two-lane blacktop. The fact that the SV6 allowed us to make up the lost time without breaking the speed limit with such a small fuel consumption penalty is a credit to the SV6’s handling balance and the extra efficiency of the High-Output V6.
The six-speed manual helped maintain consistently light throttle openings for every speed, incline and road change.
Insights: There were some big lessons in this stage. Eating, navigating and economy driving don't mix. A navigation error can generate big costs in time and fuel. Preparing a summary sheet of key route changes and approximate distances can be useful if driving on your own in an unknown area.
School zones are now a fact of life across Australia even impacting on Australia's main capital city routes. Slowing down and building up speed costs fuel and time so travelling outside these times can make a difference.
Minimising driver distractions near key route changes is not a bad idea either when they can come and go so quickly while travelling at freeway speeds. The writing on signs for minor roads throughout rural Australia is generally too small to allow a safe stopping distance while travelling at open road speeds so slowing down before you reach them can avoid an error. While this wasn't the cause of our navigation error, it was certainly a factor.
STAGE 3: WINGHAM TO KEMPSEY
Model: VE SSV manual
Target: 9.8lt/100km
Our Figure: 10.2lt/100km
Report: Again, another delay to get into our next car forced us to check out last on this stage. This SS V was the exact car which CarPoint took from Melbourne to Sydney and back in September (for more click here) and thus we had already learned that it had an open-road fuel economy 'sweet spot' at 100-110km/h in sixth gear.
The photographic crew who had delayed our departure on the previous stage was now in front of us and travelling at 20 km/h below our optimum speed if we were to meet the time and fuel consumption target. The only choice was to hang back and maintain our own pace until an opportunity to pass came up.
The second part of this stage was a wild and winding corrugated gravel road with several climbs. Fortunately, we were able to sneak past before this section but the big SS V was under pressure to make up time where it was least suited.
Wide low profile tyres made the SS V skittish in tight, corrugated corners on ball bearing gravel but the car’s inherent balance meant that it never put a foot wrong as we maintained a good average speed with little loss in momentum. Given that we were forced to spend most of the fuel-saving open road section of this stage in fourth and fifth gears, the final result of 10.2lt/100km was a real credit to the SS V.
Insights: Some big 'learns' in this stage. Drivers who travel well below the speed limit on rural roads are a fact of life in Australia.
There is little to be gained by hanging off their back bumpers with the engine screaming in a lower gear, raising fuel consumption, tempers and wear on everyone waiting for a non-existent opportunity to pass. If you don't have a time limit and the car in front won't pull over, it is usually better to drop well back then drive at your own pace.
STAGE 4: KEMPSEY TO COFFS HARBOUR
Model: VE Omega LPG auto
Target: 12.1lt/100km
Our Figure: 13.39lt/100km
Report: The base Omega with its just adequate Alloytec engine and busy four speed auto (that needs to slip to cover the lack of ratios) is not one of our favourite cars. While the gas conversion is a good one, it saps power the Omega doesn't have to spare.
This final section for Day One took us through several heavily populated area so the day's delays dropped us into stop-start peak traffic not factored into the original economy target.
Even if we met the designated time target, it was still going to be a close call to check in and make the evening meal so I tossed away any pretence of an economy drive in the closing stages.
I fully expected a fuel usage blow-out to around 16lt/100km but was staggered to learn that the car had still achieved 13.39lt/100km on LPG despite a fair proportion of rushed stop-start outer urban driving. This is a good result given Holden's own combined fuel consumption figure on LPG is typically 40 per cent higher than petrol.
Insights: Everyone at some stage is under pressure to make up time while trying to stick to the speed limits.
Although more aggressive acceleration and braking in the closing stages helped make up time without impacting too heavily on the overall figure, I was not happy about the way I was driving. In hindsight, I needed to address the ongoing delays long before it reached this point.
It was a timely wake-up call not to get behind the wheel while frustrated by an unresolved issue that needed to stay outside the car.
STAGE 5: COFFS HARBOUR TO CASINO
Model: WM Caprice V8 auto
Target: 9.6lt/100km
Our Figure: 10.06lt/100km
Report: This was a classic undulating rural drive with superb sweeping bends punctuated by diverse bush scenery. With the frustrating delays of the previous day eliminated, it was time to enjoy the drive in the best car on the event for this type of travel.
The WM Caprice is an impressive piece of kit, though after time in the car for my money the interior is a little too clinical. Comfort, suspension control and handling balance meant that momentum of this big heavy car could be maintained no matter what the road threw at it.
With most of the stage behind us, we then hit a traffic jam in the middle of nowhere. Not just a delay or build-up of cars, it was a full gridlock that was as bad as anything you would find in Sydney or Melbourne.
Half the Holden fleet struck the delay and were stationary for up to five minutes. Under the rules, no one could turn off their engines. The delay then meant that the road works further up the highway were in full swing generating further delays.
There was no way we could cover the lost time without travelling at illegal speeds so I stuck to the original plan of replicating a careful everyday driver. Prior to the traffic jam we were on target to match the engineer's figure yet the final result was much better than expected given the big Caprice was stationary and idling for up to seven minutes during this stage.
Most of the front runners from the previous day who were caught up in this were knocked out of contention when there was no way to avoid the time penalties.
Insights: The vagaries of road travel… Idling while stuck at the lights or at road works does cost money so there are several things you can do. Shut down the engine if the delay is going to be long. Shut off the air-conditioning and open the windows if there is a breeze. (For any short to medium delay where you need to keep the engine running, shift the auto into neutral so the engine's not pulling against the transmission as several European cars do automatically.)
On a big picture level, a little local knowledge can go a long way. Avoiding the end or beginning of a work shift at a local factory even in rural areas or timing your journey before and after road crew shifts can save fuel and time. Cows crossing rural roads early or late in the day on their way to milking would often trip me up until I learned to factor them into my travelling times.
STAGE 6: CASINO TO NERANG
Model: HSV E Series GTS auto
Target: 9.6lt/100km
Our Figure: 11.59lt/100km
Report: This was one stage where I thought I had done everything right short of the more extreme fuel-saving techniques. I could tell that even my navigator, HSV Managing Director, Phil Harding was as surprised as I was by the fuel economy deficit.
The big GTS had given us a reality check. This was potentially the thirstiest stage for a driver not driving for maximum fuel economy when it was steep with tight corners.
The savings from maintaining momentum down hills and up the next with foot off the accelerator and straightening corners, were potentially the greatest in the GTS with its extra levels of roadholding, huge rubber and massive engine. After all, the GTS packs over 400hp in the old language and weighed in at over 2000kg with occupants and luggage.
Gentle driving on its own is not going to be enough to make a big impact on fuel consumption in hilly conditions when the weight, tyre drag and momentum have to be managed more consciously.
Having said that, the figure we achieved could easily be replicated by any GTS driver taking the family for a Sunday drive through the hills. In that context, it is still impressive.
A quick survey of the results revealed that previous GTS drivers also overshot all but one earlier target by significant margins. The engineers probably used the full manual shift facility to maintain optimum engine revs and momentum to set each target.
I plead guilty to paying more attention to what Phil Harding had to say about his future plans for HSV....
Insights: Conventional wisdom says that a 300kW-plus muscle car is a gas guzzler. Any car that can maintain 11.59lt/100km through a mountain drive with climate control running flat out and automatic transmission left to its own devices, while the driver enjoys such effortless pull up the hills is not doing badly.
The impressive fuel control in HSV models and spread of ratios in the latest six-speed autos have transformed the fuel economy of these big Aussie performance cars.
Assuming, of course, you can resist sinking the boot in as most have catalytic converter protection modes under high throttle loads that dump extra fuel in to reduce exhaust temperatures.
At least you have the choice compared to the old days when you had to switch off a big V8 just to let the petrol bowser catch up and get some fuel in the tank.
WHAT THE BOFFINS SAY -- ECONOMY TIPS YOU CAN USE
Holden's engineers offered a number of tips to the Indy Fuel Efficiency Drive participants. While some apply to the GM products specifically (eg: most fuel efficient engine revs), most of the tips can be used in everyday driving to maximise your fuel dollar -- no matter your brand or model of car.
Here's what Holden's boffins had to say...
- Drive smoothly – avoid aggressive pedal inputs for both throttle and brake.
- Accelerate slowly – particularly on gravel and slippery surfaces.
- Avoid unnecessary steering input – each sideward movement causes drag.
- Conserve momentum – avoid severe decelerations and use rolling resistance rather than brake input if traffic conditions allow.
- Anticipate traffic flow - keep a safe distance to keep travelling with the traffic flow.
- Drive in high gear - the most efficient engine speed (for Holden’s V6s and V8) is around 1500-2500rpm.
- Shift early (manual transmission) - change up as soon as practical and before revs reach 2500rpm.
- Skip shift (manual transmission) - skip gears if practical (1st to 3rd, 3rd to 5th, etc)
- Second Gear Start (manual transmission) - pull away in second gear if practical. (JK: If starting in second involves too much clutch slipping be aware that the shortened clutch life will negate any fuel savings)
- Tap up, tap down - use the sequential shift in the auto if wanted.
- Cruise Control - use cruise on steady state roads. Avoid cruise on uphill sections with auto transmission.
- Use climate control air-con setting sparingly - keep air-conditioning on minimum comfortable condition (JK: This means operating the air-con only long enough for a comfortable temperature then turning it off)
Related reviews:
Large Six or Medium Four? A case study
Pipes and sippers - Wheels magazine compares hybrids and their conventional alternatives