Diesel, Petrol or Hybrid: An Impossible Choice

Some stats came to light recently that suggested that a diesel variant of the same car need to cover a staggering 32,000 miles before recouping the extra outlay over a petrol model.

I’ve seen similar figures bandied around in the petrol versus diesel debate that suggest a figure between 20,000-50,000 miles is common to make the premium for buying a diesel model worth paying in terms of the money regained at the pumps through superior economy – on top of the money saved on road tax or Benefit-In-Kind company car tax.

Measuring real-life running costs is fairly tricky – such calculations assume a recent figure for petrol and diesel costs-per-litre at a time when both are fluctuating significantly. And assumptions have to be made about likely mileage per annum – 12,000 per year is a frequent figure. Add on to that unknowables such as driving styles and changes to road tax in the future and such calculations start to look like a stab in the dark.

“OK, here we go, one Auris Hybrid coming right up…”
Differences in specifications levels, body styles and even transmissions can be hard to compare across car ranges, even within the same car range. Forget trying to compare a Focus to an Astra; trying to compare a diesel Focus to a petrol Focus is hard enough.

Power and torque considerations are likely to be significantly different on petrol and diesel models. Who’s to say that a 1.8 diesel is really comparable to a 1.8 petrol if the performance figures and costs are noticeably different? Some manufacturers offer specifications only with a diesel engine and not on the notionally comparable petrol engine, and vice versa.

Comparing like to like

All of this makes trying to compare like-to-like incredibly difficult. You might think that Toyota’s Auris is one of the easier cars on the block to compare, because it has petrol, diesel and hybrid powertrains in the same body styles. But no.

Toyota’s Auris Hybrid five-door comes with a 98bhp 1.8-litre engine and CVT transmission (although there’s also an ultra-low 89g/km model). It returns a combined 70.6mpg and emits 93g/km of carbon dioxide so it’s exempt from road tax and the congestion charge. It costs £20,145 in the well-specced T4 trim.

“Hmm, best compare it to the Focus first though…”
The nearest comparable petrol Auris might appear to be the 132bhp 1.6-litre V-Matic that returns 42.8mpg. It emits a fairly high 153g/km against the hybrid’s 93g/km but its performance levels are in a different league to the Hybrid. It costs £17,435 in sporty SR trim, which is the highest available.

There’s also, if you can stand it, a diesel option to throw into the bargain. For the record the 1.4-litre diesel in the Auris returns 60mpg and emits 125g/km with a 62mph sprint of 11.9 seconds.

On Toyota’s specification page a figure of 66Kw is given as power output, where people normally expect engine power in brake horsepower (which, in this case, is 89bhp – this figure is provided on another page but I went to the trouble of finding on online converter to find the figure myself). In mid-range TR trim – the highest the diesel can be paired with – its costs £18,025.

“And maybe I should size up the petrol versus the diesel…”
By now we’re so far away from comparing like to like – even if you’ve managed to follow all of this – that you might as well stick a pin in a Toyota brochure and buy whatever it lands on. But it gets harder still. Because the Auris Hybrid’s specifications levels are much higher than the standard Auris.

The Hybrid begins at the already-high T4 level, while the boggo Auris only gets as high as SR spec, which isn’t as well-equipped and veers towards a sporty nature, further muddying the water.

So, fuel economy, CO2, acceleration, top speed, fuel type, transmission type, specification, body style, list price, running costs. Good luck with all that. To make matters worse you haven’t even factored in which cars you like best out of the many dozens of permutations you can go for. No wonder car buyers are so baffled.

It’s tempting to ponder whether manufacturers deliberately obfuscate trim levels to make it harder to make direct comparisons between cars – making more expensive models seem more attractive through extra kit and higher specs. You want the petrol or hybrid models? You pay more for a higher standard spec.

Toyota is not alone here – all manufacturers are guilty of this information overload and complex engine-and-spec combinations that conspire to make a clear choice unattainable.

From here, dear car buyer, it gets worse. Because once you’ve driven the three different cars – assuming you haven’t simply called the whole thing off and bought a bus pass – you’ll be well and truly bamboozled.

In striving to give us more information, more choice, manufacturers have actually made weighing up the choice between their various cars an utterly impossible one.

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