Petrol prices

Mazda is set to buck the trend toward higher octane fuel with its next-generation SkyActiv petrol engines, but will the federal government thwart its effectiveness?

The Australian Automobile Association has challenged the federal government over its claims that motorists will benefit from having to spend less on fuel with the introduction of stricter emissions st

We're very happy with our Kia Sorento diesel, but we're considering moving to a top of range Sportage next time we buy. Normally, we would just get another diesel, but having just got back from Europe where diesels are very much on the nose with some major cities considering banning them, I'm wondering whether we should reconsider petrol. What do you think?

The cost of filling up most cars could be about to soar by more than 10 cents per litre with the federal government floating a possible plan to ban regular unleaded petrol in Australia.

When an oil company says its new super fuel is special you have a right to be sceptical.

Motorists are paying as much as 13c a litre more at the petrol bowser as fuel retailers gouge "unreasonably high" profit margins, Australian Competition & Consumer Commission figures show.

Ricky Muir wants new laws to stop motorists being ripped off at the bowser after Melbourne petrol prices averaged $1.20 last week despite oil prices falling to a 10-year low.

Sydney motorists have been slugged an extra $470 for petrol over the last five years compared to Melbourne drivers.

Fuel consumption claims aren't worth the label they're printed on.

At the start of February, the average weekly price of diesel was $1.26 a litre, 14c dearer than petrol. At the time of writing, petrol was roughly 2c a litre more expensive.So why the swing and what does it mean to motorists? Caltex says there is no intrinsic link between petrol and diesel, other than the fact that they are both made from crude oil.There's no reason to rush out and buy a diesel car or SUVEach has unique supply and demand curves — diesel becomes more expensive in the northern winter because it is used for heating in North Asia, while petrol prices head north when Americans do more summer driving.So the bottom line is this isn't a long-term trend and there's no reason to rush out and buy a diesel car or SUV.In fact, the way some car companies are pricing their diesel variants, you'd probably be better to steer clear because the payback period is way too long.Diesel isn't startlingly more economical than the petrolThe diesel version of Hyundai's new i30 is $25,990 drive-away, while the petrol version is just $21,990 drive-away and includes a $1000 Eftpos credit.The price discrepancy is made worse by the fact that the diesel isn't startlingly more economical than the petrol, using 4.8L/100km to the petrol's 7.3L/100km.At the average of 15,000km a year, and with both fuels at $1.30 a litre, the diesel version saves $468 a year. That means a payback of more than 10 years.Using the same formula, the 2.0-litre petrol Mazda CX-5 Maxx Sport costs $6531 less than the diesel variant but costs $136.50 a year more to fill, because it uses just 6.4L/100km to the diesel's 5.7L/100km.The payback time? About 48 years. Bottom line is if you're looking to save money by buying a diesel, forget it.It's not that simple, though — the diesel CX-5 has more power and double — yes, double — the torque of the petrol. So buy diesel if you want performance. Just don't buy it for the bottom line.