The claims, the reality

* They claim to offer better economy * they also cost more to buy * but are they really worth it we find out...

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What Car? Staff
06 April 2011

The claims, the reality

They cost more but are claimed to offer better economy. Are petrol and diesel superfuels too good to be true? Peter de Nayer investigates.

Sales of so-called superfuels are rising, and its little wonder: with their exotic names and bold promises of better efficiency, it would be easy to think that they could hold the answer to increasing fuel prices.

As a result of being made from higher-quality ingredients and being more finely distilled, superfuels contain more energy than standard fuels. Their makers claim they can provide extra mileage benefits of up to 25% which would be more than enough to offset the extra 4-9% cost for buying the fuel.

Here, we independently test those extra mileage claims in real driving conditions to find out if superfuels really can help make our motoring cheaper.

Click here to see how superfuel claims stand up to scrutinyOur rigorous tests took several months, and were carried out by What Car? fuel expert Peter de Nayer, a former senior research engineer for the AA. Each car was tested in every condition, from city to motorway, testing each fuel over hundreds of miles. Were confident that, if asked, we can repeat our results to within plus or minus 0.5%.

We compared both petrol and diesel superfuels to determine the benefits. The petrol tests were conducted in a VW Polo 1.2 SE and the diesel tests in a BMW 318d Touring.