PERHAPS the main reason for the relative lack of success of LPG-fuelled Falcons is the great improvement in economy for petrol models, including turbocharged variants.

However, while the fuel economy of LPG-powered cars is not measured simply in litres per 100 kilometres but at the bowser, where gas costs much less than half as much per litre, the EcoLPi G6 still scores surprisingly well on absolute consumption, readily dropping below 10 litres per 100km at highway speeds.

With LPG priced around 60 cents per litre at the time of writing compared with $1.50 for unleaded, it is easy to see how dramatic savings are available.

Typically, a six-cylinder petrol-engined Falcon averages about 7.5L/100km on the highway, so it uses about three-quarters as much fuel, but a 1000km interstate journey would cost about $102 for the petrol Ford and $60 for the LPG car, so there is a major saving to be had.

The cost for the same trip with a small Toyota Corolla, even at 6.0L/100km, would cost $90.

Obviously the mass of the G6 means that there is less advantage in urban and extra-urban driving, but it is still considerable.

The EcoLPi engine delivers the same peak torque of 409Nm at 3250rpm as its petrol equivalent, which requires 95-RON premium fuel to achieve this figure, while maximum power is now 198kW at 5000rpm – 13kW more than a V8-engined XR8 from the AU era. That’s progress.

The improvements over the previous E-Gas engine are considerable – 27 per cent more power, 10 per cent more torque and better fuel improvement in the order of 12 to 15 per cent.

The G6 EcoLPi has significant advantages over its identically priced Holden Commodore Berlina rival, particularly an additional 23kW of power and two extra ratios in its six-speed automatic transmission.

For those unfamiliar with Ford Australia’s latest model nomenclature, the G6 sits roughly where the old Futura used to be in relation to the base model and the G6E is like a Fairmont. In practice, all FGs are equipped to higher standards than their predecessors.

While the XT is aimed essentially at fleets, the G6 with its more refined appearance and long list of standard features is intended to appeal to private buyers. At $45,890, the EcoLPi costs $2400 more than a petrol G6, but large discounts are readily available across the whole Falcon range.

All Mk II FG Falcon sedans have side curtain airbags, for a total of six, and have attained a five-star ANCAP safety rating.

The FG cabin is beginning to feel a little dated, despite being neat and efficient. The arrival of vehicles such as Hyundai’s i45 and i40 are raising expectations about interior design.

Good quality materials are evident throughout the G6. Elegant alcantara and cloth seats, soft-touch dashboard plastics and switchgear that is neatly arranged in a small space contribute to the impression that Ford Australia’s designers have learnt a great deal from the disaster of the AU Forte and Futura (where, in essence, the company was trying to sell a stripped-out fleet car to private buyers).

Most significantly, there is not the rear legroom you expect in a car of this size. This is a perennial Falcon problem, as anyone who has had to struggle out of the back seat will know, especially if the front passenger’s seat was set right back.

The FG is better than its predecessors, but the shape of the footwell and the distance up to the bottom of the door frame remains excessive. And the very deep and thick transmission tunnel means there is nowhere comfortable for the middle passenger’s feet, unless they are splayed around the hump, intruding onto the other passengers.

Interior width has been claimed for many years to be one of the Falcon’s great attributes but it is a largely theoretical virtue.

Fortunately, front occupants fare much better. The seats are very comfortable, but there seems little point in having power adjustment of the seat height when much of the other configuring must be done manually.

The driving position is less than ideal. There is a considerable range of seat adjustment, but most people will find the steering wheel correctly placed only when the seat is set quite low.

The wheel itself is adjustable through a modest range from too-low to much-too-low. At least it is elegant to look at, nicely trimmed in leather and all the wheel-mounted controls are well arranged and clearly marked. You get some electric adjustment of the driver’s seat, but you’ll still be groping around for manual levers for some functions in an obvious compromise on cost.

It remains a curious oversight on Ford’s part not to have a redline on the tachometer.

One advantage of the G6 over any Commodore is the split-fold rear seat, but unfortunately the gas tank requires compromises with the boot and spare tyre. You can opt for a repair can and have unimpaired boot space, or a full-size spare that takes up half the boot, or compromise with a space-saver spare that leaves a bit more boot space. None of them are ideal and seem to defeat the purpose of having a big Aussie car for a big Aussie land.

Yet all these complaints pale into insignificance in view of the overall job this car does.

There is no important difference in power delivery between the EcoLPi engine and the petrol six, which means oodles of torque where you need it for easy climbing and effortless overtaking.

And all the while fuel economy borders on the unbelievable when you come to pay after refueling.

Dynamics have long been a Falcon strength, but the level achieved by the G6 is especially impressive for a car without XR6-style sporting aspirations.

The steering has weighting to suit the enthusiast at lower speeds but is too light on the open road while body roll is well controlled and you can corner with zest.

Most customers will care more about ride quality and overall levels of refinement, which approach BMW 5 Series standards.

In summary, Ford Australia continues to lead the field when it comes to dedicated LPG motoring. The only compromise is in the packaging of the boot and spare wheel. In terms of economy, performance, dynamics, ruggedness and comfort for four adults, the G6 EcoLPi is a standout sedan of considerable flair.