Hey, it's great while it lasts. Cheap petrol, that is. But just when you thought the welcome return of 'affordable' juice made it safe to re-enter the big-car waters, there's something to be said for that niggling doubt.
Of course we're not within coo-ee of last year's traumatising surges towards $2.00/litre. However, the recent good-old days of $1.00/litre are already the stuff of memories as fuel prices bounce around beyond comprehension. Diesel's unfathomable fluctuations relative to petrol are another case in point.
No-one knows where or when the prices may stabilise, if ever, but one thing's crystal clear. Fuel pricing is still (or again) an issue raw enough to drive home the message that consumption is influentially prominent in thinking buyers' consciousness. For most, the days are gone when the fill-'er-up cost of a tankful was scarcely worth a shrug of no-worries indifference.
In the current climate, economy counts as never before, as much in dollars/distance terms as in the simple price per litre context. And even that's not the half of it. The environmental implications of CO2 emissions are an increasingly critical aspect of the consumption equation. The two are inextricably linked.
Nature has arranged things so CO2 content varies from fuel to fuel. Burning a litre of petrol, for example, releases almost 2.4kg of carbon dioxide to the atmosphere. A litre of diesel frees over 2.6kg of the world's least favourite greenhouse gas, while there's about 1.5kg's worth in a litre of LPG.
Taken at face value, however, those numbers are misleading because they don't reflect how much noxious stuff comes from the exhaust over a given distance. And that depends on each fuel's energy efficiency; how good a worker it is.
Typically, it takes almost 50 per cent more LPG than petrol to drive a car the same distance at the same speed. For instance, the ADR 81 combined drive-cycle test credits the Falcon G6 with using 10.1L/100km whereas the equivalent LPG model rates 14.9L/100km.
Although the Falcon LPG model indeed provides fuel-cost savings (for the time being, anyway), its 240 grams/km CO2 output is virtually line-ball with its 241g/km petrol sibling.
Don't think for a moment that the significance of cars' CO2 counts are lost on our politicians and revenue raisers. Sooner or later Australia will surely follow the UK and like-minded Europeans in adding a CO2 levy to cars' tax component. The situation overseas shows that a tax on fuel consumption and/or emissions irrevocably nudges mass-market car buyers' priorities towards more efficient, lower emission models.
In that light, and to slake your curiosity about which of Australia's cars are leanest and greenest, we've researched those that consume just 4.5L/100km or even less, according to the ADR81 combined driving-cycle test.
There are currently six super sippers -- the Audi A3 Sportback 1.9e TDI, Citroen C3 1.6 HDi, Citroen C4 SX EGS 1.6 HDi, Fiat 500 1.3 TD, smart fourtwo mhd and Toyota Prius.
We initially thought this elite group numbered seven, because Fiat's semi-automatic Punto Dynamique 1.3 TD registered a laudable 4.5L/100km. However, it's now discontinued, and, showing the difference a transmission can make, the manual Punto 1.3 TD just misses the cut.
That said, the former's 4.6L/100km rating easily qualifies for the 5.0 to 4.6 litres/100km group. That's for another time. Here, we're concerned only with the best of the best.
Audi A3 Sportback 1.9 TDIe (more here)
Audi mightn't be a brand you ordinarily associate with the economy-car genre. But, make no mistake, the A3 Sportback 1.9 TDIe takes its fuel-saving mission very seriously.
Outwardly, the 1.9 TDIe clearly hails from the same stable as other A3 Sportback models. About the only visible differences are the steel wheels and low-rolling-resistance tyres.
As you'd hope, the TDIe is no $38,900 poverty pack. It maintains the usual A3 equipment levels, including six airbags and a full clutch of electronic driver aids.
Besides the intrinsically thrifty 77kW, 250Nm turbodiesel engine, the 1.9 TDIe brings its own economy-shift indicator to complement the five-speed manual gearbox which has made-for-the-job ratios. The engine's thrift-conscious electronic management system is also exclusive to the 'e' model.
The result is a very driveable car, one of the roomiest (and heaviest) here, capable of doing 0-100km/h in 11.7 seconds (claimed) and brushing 194km/h flat out.
Yet it rates 4.5L/100 fuel economy and 119g/km CO2 output for the combined drive cycle. That means some 1200km from the 55 litre tank. And three years down the track, according to Redbook, the fuel-savvy TDIe could, on current calculations, attract about 55 per cent resale valuation.
Citroen C3 HDi, 1.6TD (more here)
Until relatively recently Citroen's C3 1.6 HDi reigned supreme and alone as the market's most economical conventional car. Although that distinction has since passed to another model, the pert little C3 1.6 HDi is still the sole conventional design among the three models boasting a 4.4L/100km result for the combined test.
Moreover, its CO2 emissions squeak under the 120g/km bar.
At $23,990 (driveaway, at time of writing), the C3 1.6 HDi is by some margin the least expensive four-door model in the sub-4.5L/100km class.
Importantly, the ante isn't achieved by reducing the equipment level to a threadbare status. Apart from lacking stability control and curtain airbags, the Citroen brings all the usual creature features, and more besides.
Not the least of the C3 1.6 HDi's attractions is its projected almost 60 per cent value retention; close to best in this group.
With Citroen's gutsy 1.6-litre turbodiesel engine peaking at 66kW and 215Nm, for a car that weighs just over 1100kg, there's no surprise that the five-speed manual C3 HDi is a comparatively spirited performer. Its capabilities include 0-100km/h in 10.8 seconds (claimed) and 180km/h top speed while the 47-litre tank assures a cruising range in excess of 1000km.
Citroen C4 SX EGS 1.6HDi (more here)
Another frugal froggie, the $30,990 C4 SX 1.6 HDi five-door hatch has impressive 4.5L/100km and 120g/km credentials. Thus, the larger-than-average 60-litre tank could be good for over 1300km between refills.
That's far from the C4 1.6 HDi's only attraction. While eking optimal fuel economy, the 80kW, 240Nm turbodiesel engine also offers enterprising acceleration, with 0-100km/h in 11.2 seconds, not to mention top speed potential above 190km/h. And given pedal-to-the-metal, the SX 1.6 HDi's rolling acceleration in the upper three gears is further quickened as the turbo's overboost feature temporarily adds more oomph to lift maximum torque to a group-topping 260Nm.
All that from a car which is one of the largest here in most respects, and not in the slightest anorexic in its weight.
Some of the C4 1.6 HDi's success in consumption and performance is owed to its EGS component, the electronic gear system. That's Citroen-speak for a six-speed transmission operated manually via the floor lever or paddles behind the steering wheel, or that can do its thing automatically when preferred.
Although Citroen mightn't be a brand that first comes to mind in Australia, the C4 SX 1.6 HDi's manifold virtues sew high-50s retained value prospects.
Fiat 500, 1.3 JTD (more here)
On the 'combined' drive-cycle calculation, the Fiat 500 1.3 JTD is the current absolute fuel economy champ. It's credited with using just 4.2l/100km, which would go a long way to offsetting the 500's bite-size 35-litre fuel capacity.
The junior Fiat JTD's mere 111g/km CO2 output also reinforces its place as one of the least emissive models available.
Teamed with five-speed manual transmission, the earnest little 1.3-litre turbodiesel delivers a modest 55kW maximum power and 145Nm torque.
On that basis you might wonder about the performance. The bonus of usefully light weight helps the 500 JTD to dash from 0-100km/h in 11.5 seconds and continue, if desired, to about 185km/h flat out. Which, it must be said, is quite frisky for a wee three-door cutey whose footprint is even smaller than the MINI Cooper's.
The Fiat 1.3 JTD's parsimonious fuel economy is available with the $25,990 Pop model and in the more upmarket $29,990 Lounge version.
Before being swayed by the Lounge's extra features, there's food for thought in the respective model's forecast value retention. The Lounge rates an excellent 60 per cent, whereas the less opulent Pop stars with 69 per cent.
Smart fourtwo mhd (more here)
In case you haven't heard, the mhd suffix for the non-turbo versions of the smart fourtwo stands for mini hybrid drive. Understand, however, unlike most hybrids, mhd doesn't include electric propulsion.
Instead, a belt-driven starter/generator powers the vehicle's electrical system and also acts as the starter for the three-cylinder 1.0-litre petrol engine that maxes at 52kW and 92Nm.
With help from the five-speed semi-automatic's revised ratios, the mhd system improves the smart's combined-cycle fuel economy to 4.4L/100km, with potential for even better results in heavy stop-start traffic. At the same time, the smart's CO2 emissions plunge to a market-leading 105g/km.
The engine switches off at speeds below 8km/h when the car is braked, and in idling phases. Engine re-starts are almost instantaneous as the driver releases the brakes, but should drivers prefer, the start/stop function can be disabled to remain inactive until the next ignition off/on starting procedure.
Available in coupe and cabrio forms, from $19,990 and $22,990 respectively, the smart mhd two-seaters are definitive city cars. In their natural environment, the performance (0-100km/h in 13.3 seconds, for example) is entirely adequate, as is their 145km/h top speed and the 33-litre tank.
Even the 58 per cent resale projection is not to be sneered at.
Toyota Prius (more here)
The Toyota Prius isn't the world's only petro-electric car, but definitely is the one most widely and strongly associated with the whole 'hybrid' genre.
After the first series Prius put hybrids on the map, the existing model has proven appeal to many people who want to do the right thing by the environment, and to be seen to be doing it. The only downside is that the Prius's chassis dynamics and driving pleasures are simply adequate, nothing special.
The Prius comes at $37,400 and $46,900 depending on the equipment/feature content. Both editions share the same slightly-below-average 54 per cent resale prospects.
Although nearing the end of its term, the current Prius remains a class benchmark for fuel economy and low emissions. For driving ease, too. Its electric continuously variable transmission (ECVT) is alone, here, in providing fully automatic operation.
Even with the group's longest wheelbase and length, the roomiest cabin and a voluminous boot, the Prius still rates excellent 4.4L/100km and 106g/km test numbers. The 45-litre tank typically sees around 1000km between refills.
Not coincidentally, the third-generation Prius, due in July, is said to do appreciably better again -- in terms of performance and fuel consumption.
Toyota has pre-emptively disclosed that the goalposts shall move to just 3.9L/100km and 89g/km when the new car arrives. It promises a 0-100km/h better than 10sec to boot. Meantime, despite vying with the Audi A3e for top weight, the current Prius's performance is class-competitive with 0-100km/h in 11.3 seconds and top speed around 175km/h. So it's still a car to be taken seriously.
THE CARSALES NETWORK'S PICKS
HARDHEAD
In the event that emissions and fuel economy are the overriding priority, and accepting the official consumption and CO2 results as gospel, the Fiat 500 1.3 JTD certainly has your number as a leader of the pack.
The feel-good Fiat is, however, at least more than two grand costlier than the patently roomier, better performing and barely more consumptive Citroen C3 HDi.
Then again, if your driving is concentrated around the city and peak-hour suburbs, and no more than two seats are needed, the wildcard smart fourtwo mhd has to be in with a chance too.
Logically, though, the winner is the ... Citroen C3 HDi.
HEARTBEAT
If you have a touch of green running through your veins, you're tickled by hybrid technology and you believe the Prius answers some of today's most vexing questions, then your quest is easily solved. Be happy...
But if you're a keen driver who prefers a conventional car even if it can't quite match the Prius's great economy and low emissions, your attention may be divided between the Citroen C4 SX EGS TDi and the Audi A3e.
Those two are closely matched in cabin size, engine capacity and performance, also fuel economy and CO2 output. Not in price, however.
The Citroen drives well enough, the Audi rather better. Although Citroen is a household name, its cars, including the C4, aren't big players in Australia. For individuality's sake, that may be a deciding attraction. Or not.
On the other hand, and appropriate to its extra cost, the Audi is mainstream brand renowned for fine build quality and a sense of classiness unmatched in this group. So, in sum, the A3e Sportback makes the strongest case as the more discerning choice on more fronts.
COMING UP - new entries to watch
>> MINI D (more here)
>> New Toyota Prius (more here)