Petrol or Diesel?

The debate has been raging for years: Diesel or Petrol: which is better?Alas, no definitive answer can be provided, in fact more and more it’s becoming a case of personal preference. As technology improves, the gap between petrol and diesel cars is getting reduced, so much so that it’s only quite a small gap now.

The Traditional Argument

Petrol: Faster, quieter and cheaper.Diesel: Better fuel economy and consumption and greater torque, resulting in better pulling power and less gear changes.

Are these points still valid?

In general, but in much more less defined terms, the traditional arguments do still stand. For example, diesels are generally louder, but then they do provide a much better fuel economy, and petrol vehicles tend to be cheaper, but not as economical.In each case or term, slightly should probably be added: i.e. diesels offer a slightly better fuel economy, if you catch my drift.


Diesels have often been labelled as damaging to the environment, based on the particulates (soot) and emissions that their engines produce. However a new, or relatively new technology, known as Diesel Particulate Filters (DPF) now regulate the emissions produced.Now, you may think this would mean a lot of ground made up by diesels on their petrol counterpart, but no.As I said it’s not clear-cut, that’s why it’s been an incessant debate in the motor trade.The DPF systems cut emissions, but simultaneously affect the efficiency of the engine. Therefore some DPF systems render diesel engines less efficient, rather than being suited to frequent short journeys as used to be the case, they now need regular long runs to feel the benefits of fuel efficiency.Similarly, the prices for diesel cars and diesel itself are perennially higher than petrol and petrol cars. As a result, they need to average a far higher mileage per year to reap the rewards in mpg.At the same time however, Diesel sales overtook petrol sales for the first time in July of this year, with 50.6 per cent of the market for that month. So, they must be doing something right.

The Flipside

Diesel is 15-20 per cent more efficient than petrol. When this is coupled with an improvement in diesel technology that is bringing diesel performance on par with petrol equivalents, diesel is as appealing a fuel as petrol.Diesel is often the choice of fleet line managers, as the initial high costs of the vehicles can be recouped in terms of mpg.A quick browse of used car websites and sales figures will also illustrate a further benefit of a diesel engine: residual values. Diesel cars are still being bought even if they’ve done over 75,000 miles; they sell well.

And finally

Just to further confuse the subject we’re going to bring up BHP and refinement.It is common knowledge that petrol engines tend to offer more BHP for their size than diesel engines. This means they have higher top speeds and quicker acceleration. But, with the advent of the T in TDI, diesel performance has improved. Once more the gap is reduced.So there you have it.There’s no real answer as to which is better generally, instead it comes down to:1. Personal preference: In short, money. Would you rather fork out more money early on and save in the long run, or pay less now and more in the future.2. Driving requirements: Diesels are more efficient, but if you don’t do enough miles, you won’t feel the financial benefits of this fact. As a result it’s vital to work out which fuel would benefit you more. To do so there are plenty of petrol Vs. diesel calculators out there e.g.