Petrol or diesel?

Driving a car powered by just electricity makes no sense, yet. But while that debate continues to be noisy and heated, the average Aussie really only cares about two fuel sources, diesel or petrol.

There’s still a stigma that surrounds diesel. Many believe it’s messy, smelly and deserves to be confined to trucks and other working-class vehicles. Others just think about the Volkswagen emissions scandal and then proceed to lose their shit.

However, most of our most popular brands have diesel options in their line-up. Take for example our Dictator Trevor Long. His has three kids and a wife that wants a very specific type of car, that is one with sliding doors. The Kia Carnival is the most obvious choice. But if and when Trev decides to get the Carnival, I know he will go for the 3.5-litre petrol V6 as opposed to the turbo-charged 2.2-litre diesel, which I reckon is just outright dumb.

And here’s why.

For a patrol car the most important thing is where on the tachometer the power arrives. Power is measured in kilowatts. The petrol Carnival delivers its maximum 206kW at 6000 revolutions per minute (RPM), basically how many times the crankshaft turns the pistons that go up and down. In other words, to get the petrol Carnival moving, you really need to put the boot in.

The four-cylinder diesel option produces 147kW at 3,000rpm. But the major benefit when it comes to a diesel engine is how and when the torque is delivered, this is measured via newton metres. Torque refers to the twisting or turning of an engine.

The Carnival delivers 440Nm at 1,750-2,750rpm, the petrol 336Nm at 5,200rpm. Basically, the petrol engine needs to work harder than the smaller diesel engine. If you need any further evidence, you only need to look at the claimed fuel economy. 7.6L/100km for the diesel or 10.8L/100km. 

But having said that, ticking the diesel engine option can add a few thousand extra dollars. They also require a different servicing regime. Plus, you will rarely see it cheaper than petrol at the pump.

Another concern buyers seem to have is the perceived clatter or rattle these engines make.

There’s little doubt you’ll know you’re driving one, especially when it comes to dual cabs. But I’ve driven plenty of European small to medium cars that keep the distinctive soundtrack at bay.

Diesel does produce harmful emissions; parts of Europe want to rid its cities entirely. Products such as the additive AdBlue attempt to stifle the bad stuff coming out the back, so owning a diesel is higher maintenance.  

In short choosing a diesel engine is a very individual choice. It may be due to lifestyle reasons such as better towing capabilities or the long-term fuel savings. 

If you are faced with the choice, I’d at the very least do the math to help decide what suits you.