A DIFFERENT MOTIVE
WE SWITCH FROM DIESEL TO PETROL POWER IN KIA’S LARGE SUV AND WEIGH UP THE COST VERSUS BENEFITS
ALLOW US A quick recap, for those of you playing along at home who may have lobbed back in late from a commercial break.
For the past four months I’ve been the custodian of a top-spec Sorento GTLine diesel all-wheel drive, the Korean company’s flagship seven-seater SUV. Contrary to my default setting, I’ve been a largely non-grumbling one. That car ended its tenure last issue, with the only real caveats to its all-round goodness being no third-row airbags and the typical diesel NVH drawbacks. Not awful, but the vibey idle was at odds with the otherwise well-polished manners, and the level of clatter under modest acceleration, while not bad by four-pot-oiler class standards, still left room for improvement.
We knew from our most recent COTY testing of both engine variants that the V6 petrol version had no such drawbacks, thanks to the joyous combination of highly combustible unleaded fuel, a lower compression ratio and lively spark plugs. We also knew that as a front driver the V6 was less dynamically adept than its AWD diesel sibling. More prone to axle tramp and torque-steer; less composed and athletic on loose or wet surfaces.
But we also understand that daily motoring life for most of you (and us) is pretty far removed from the relentless punishment of COTY testing. So when the opportunity emerged for me to spend a month with this top-spec GT-Line petrol front-driver, of course it was a fine idea. It’s a chance to see how it fares in more genteel real-world conditions (and keep me off Sydney buses where COVID probably lives) as well as allowing me to compare real-world consumption and running costs of diesel versus petrol.
But first, let’s take a hushed moment
to reflect on the quietness of the petrol variant. It’s best appreciated stationary, ideally while treating the ears to some quality decibels from the excellent Bose audio system specific to GT-Line. The car will only allow the accessories to run for a few minutes with the engine off, so an internal combustion accompaniment is unavoidable. In the diesel, during any quieter passage of music – like the Nirvana ‘soft-loud-soft’ signature that became a ’90s genre convention – the idle is ever-present; an inescapable background distraction. In the petrol, this is replaced by the sweet sound of silence. I may be a bit NVH OCD, I’ll own that, but by any measure the V6 is beautifully muted at idle, with the gentle whisper of the ventilation and seat-cooling fans actually more audible than the lump under the bonnet. The lack of any vibration through the steering wheel is almost a bonus.
On the road, the V6 doesn’t have the effortless low-speed shove of the diesel, but it’s sure not lethargic, and again the more refined, attenuated aural experience is a compensation plenty will find persuasive. In normal driving, on dry roads, the front-drive layout isn’t an issue, especially in isolation and when not being compared back to back with the AWD model. Different story in the wet or on dirt, but I did cover that in the February issue so no need for further elaboration.
Instead, let’s get to the battle at the bowser, ignoring ADR consumption numbers and instead dealing with typical real-world scenarios.
My overall consumption (mainly urban) in the diesel was around 9L/100km; in the same conditions, the petrol model seems set to settle around mid-14s. Both have tank capacities of 67 litres, so at current prices (diesel $1.27 and 95 RON unleaded $1.50), it costs around $85 to fill the diesel, translating to around $11.40 for every 100km travelled. In this petrol version, a fill is around $100, and the cost per 100km is nearly twice as much; a hefty $21.75 thanks to the double whammy of higher consumption and higher fuel price.
For the family doing, say, 350km per week, the extra cost of petrol will be around $36 over what the diesel owner is paying.
Don’t forget the diesel AWD models add $3000 to the Sorento’s purchase price (regardless of which of the four spec levels you choose), so it would take around 21 months for the fuel saving to pay for itself. But factor in slightly higher resale, longer touring range and the AWD security, no wonder the diesel is currently the bigger Sorento seller.