Petrol or diesel? Choose wisely

During these uncertain financial times amid the Covid-19 crisis, consumers are looking at every possible way to try and ease the impact on their wallets. Buying down has become a trend in the car market of late and is expected to increase as motorists look for ways to lessen their monthly financial burden.

Apart from saving on repayments, spending less at the pumps is another way to lessen your load. Despite fuel prices slumping to record lows during the height of lockdown, rising global demand has already contributed to a massive hike in June with more predicted for the coming months. As fuel prices return to pre-lockdown levels and travelling restrictions are eased further, the demand for fuel efficient cars should rise too.

Even though fully electric vehicles and hybrids are more affordable to run than cars powered by traditional internal combustion engines, they are largely out of reach of the average South African due to their bloated prices which are inclusive of exorbitant import taxes and duties. This means for most car buyers it comes down to a simple choice between two internal combustion engines: petrol or diesel.

A diesel-powered car is more expensive to produce and assemble than its petrol equivalent because the powertrain has more moving parts, but it returns better fuel economy which is estimated at anything between 10 and 30%. And more often than not, diesel trades for less than petrol. At the current going rate diesel sells for almost R1 a litre less than petrol, but the difference can be even bigger as the price is not regulated like that of petrol and some filling stations discount diesel prices more than others.

There are more to diesel engines than saving on fuel. Picture: iStock

While it might seem like a no-brainer to opt for diesel when you are presented with the option, a few calculations might persuade you into sticking to petrol instead.

Let’s take a simple example. Hyundai offers a Creta in 1.6 Executive guise in a choice of petrol of diesel engine. The two are similarly specced, with the drivetrain being the only thing that separates the two at a price difference of R46 600. The petrol version costs R399 900 and the diesel derivative R446 500.

As far as fuel economy goes, the Korean manufacturer claims that its petrol offering uses 8.4 litres of fuel for every 100km and the diesel 7.4L/100 km. At the current rate of 93 octane fuel being R13.20 at the reef and diesel 50ppm selling for around R12.40 per litre, the cost per kilometre on the petrol model works out to R1.33 compared to the R1.10 of the oil-burner. In order to determine whether diesel will save you money, you need to apply this 23-cent difference per litre to the distance you plan to travel.

If you complete 2 000 km per month, you will save R460 per month which will work out to R5 520 per annum. If you apply this saving to the initial R46 600 you paid extra for the diesel derivative, it will roughly take you 80 months to break even compared to driving the same distance over the same time with the petrol model. In that case, if you are not planning to keep the car that long or complete less kilometers per year, the diesel model makes no financial sense.

It is estimated that a third of all new vehicles sold locally since 2016 are diesel-powered.

The determining factor should be the distance you cover. The more you drive the more likely you’ll benefit from diesel’s superior fuel economy. If you cover 5 000 km a month, you will make up the initial price difference in fuel economy alone within three years, after which it becomes a case of you saving 23 c on every kilo.

But it’s not always as straight forward as the example of the Creta being offered at the same spec level in two engine choices. Some manufacturers like Suzuki doesn’t offer any diesel models in South Africa, there are plenty of local model ranges across a wide variety of manufacturers that don’t include oil-burning derivatives, there are differences in specification levels between petrol and diesel derivatives in model ranges that do include diesel derivatives and then you also get a model range like the Hyundai Sante Fe or most van line-ups that aren’t locally offered in petrol.

Because diesel-powered engines are significantly more expensive, manufacturers seldomly offer oil-burning derivatives in their lower segment model ranges as this would defeat the whole purpose of offering more affordable cars. In fact, the cheapest new diesel-powered car available locally is the Mahindra KUV100 NXT 1.2 D75 K6+ at R219 999 which is a whopping R85 099 more than the most affordable petrol car, the Suzuki S-Presso 1.0 GL at R134 900.

Diesel offerings increase throughout the market’s mid segments and into the higher segments, with various performance offerings also available. While high performance models mostly play second fiddle to its petrol counterparts in the speed stakes, they offer the best of both worlds. They are very respectable performance cars while also lighter on the juice than petrol engines.

The Mahindra KUV100 NXT 1.2 D75 K6+ is the most affordable diesel passenger car on the local market.

The fastest time The Citizen’s Road Test Editor Mark Jones has recorded during a high performance test in a diesel car in going from 0 to 100 km/h was 5.33 sec in a BMW X5 M50d. Along with the car’s claimed fuel efficiency of 7.4L/100 km for a vehicle weighing almost two and a half tonnes, you simply won’t find a petrol version striking a better balance on those two fronts.

That is a far cry from the old myth that diesel engines are messy and better off in trucks and tractors than in passenger cars. And while they have become highly sophisticated, modern day diesel engines are still as dependable as ever despite our local industry standard of 50 ppm (parts per million) grade fuel contains more sulphur than the 10 ppm used in Europe. And speaking of Europe, the clock might be ticking for internal combustion engines on the Old Continent, especially diesel, oil-burners are not going anywhere over here in Africa.

“Diesel engines are reliable and capable of powering a vehicle for hundreds of thousands and even millions of kilometres,’’ Hugo Grobler, national franchise manager for diesel engine injection repairs specialists Adco recently said. “Pressure may be increased to have only electric-powered vehicles in the UK by 2045, but diesel is here to stay.”

The fastest diesel-powered car The Citizen has tested is the BMW X5 M50d.

Grobler did caution that although diesel works out cheaper in the long run, it requires repair and maintenance and that cutting corners and costs by not consulting specialists can end up being very expensive. And this brings us to another major factor in any car buyer’s choice of engine, namely maintenance.

While almost all new cars nowadays include service plans for a set numbers of services which can be extended, taking care of your vehicle once this runs out needs to be taken into consideration. While diesel cars’ service intervals are mostly on par with petrol-powered vehicles, there are manufacturers like Toyota which diesel service intervals are set at every 10 000 km and not 15 000 km which has become the industry standard for the majority of petrol and diesel cars. Having to pay for a service out of your own pocket at every 10 000 km instead of every 15 000 km will definitely play a role in your finances.

But the numbers aren’t always the be-all and end-all. You might prefer diesel over petrol for reasons other than potentially saving money alone. If you are into off-roading, it might be the torque it offers at lower revolutions that you’re after. If you are into towing, the superior pulling power might be the persuading factor. Or maybe you are just a sucker for the good old familiar idling sound that differentiates it from a petrol engine.

At the end of the day a diesel engine can have many benefits, but if they don’t suit your needs or lifestyle, you’ll just end up paying more for something you don’t need. And that is the last thing you’ll want to do during tough times. Make sure to do your research and not make an impulsive decision when the time comes to choose which engine is right for you.

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