Despite being one of the first people in my locality to own a diesel car some 25 years ago, at which time I started subscribing to your excellent magazine, I must confess that I reverted to petrol (Aaaaaargh! Doc) in early March, as I drive a lot less miles than in years gone by.

My new car is a Renault Clio 0.9 TCe Eco model and I have been pleasantly surprised by the good performance and decent economy which this particular model offers.

The combination of high gearing and a punchy micro-turbo engine provides relaxed driving and good hill climbing ability that, to all intents and purposes, feels like a small diesel with the added benefit of rapid overtaking when revved hard.

Although my driving is mostly in towns and on the surrounding motorways, I am currently getting 51mpg, which is improving all the time (I only have 2,500 miles recorded on the clock so far). Whilst I still like the robust feel of driving diesel cars, I preferred it when the engines were a bit simpler, without DPFs and so on, and I particularly enjoyed both my Renault 19 turbodiesels, which both gave an easy 54mpg with great performance.

My next move will likely be to consider an electric vehicle in four years time, when the Clio’s warranty expires, as the engineer in me is fascinated by the technology.

I will continue to subscribe to Diesel Car which is an exceptionally good read in its present format and enhanced by the inclusion of alternative energy vehicles.

Brian Griffiths, Dunfermline. MCIBS ChB, PDA Renewable Energy Systems.

All the environmental controls have taken away the robust simplicity of diesel engines and also stifled the efficiency to a significant degree, I feel, which is unfortunate.

The fact remains though that diesels are fundamentally more efficient, as a result of the higher compression ratio, but petrol power has recently closed the gap. Cylinder compression ratio isn’t a true guide to thermodynamic efficiency though, as the cylinder pressure is enhanced by the turbo boost pressure.

It’s something which your letter has now spurred me to look into more deeply. I’ll hopefully have some findings that may throw some light on this issue, in due course.

But there still aren’t any petrol cars that approach the economy of the best diesels, and for heavy cars like big 4x4s and SUVs, there’s still no argument in favour of petrol power that is sustainable, unless you’ve the income of a Premier League footballer.

And those fast-revving little petrol turbos are inevitably going to wear out quicker than diesels!

Best regards,

Doc Diesel

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