So-called `super-fuels` such as Shell V-Power, Tesco Super Unleaded and BP Ultimate Diesel do not save money, do not improve performance and do not help the environment, according to Which? Car magazine. Its tests against standard fuels found that:
:: Shell V-Power gave a a marginal power increase. But filling a car on this petrol for 12,000 miles cost £115 more than using Shell's standard petrol. Tesco Super Unleaded actually decreased the power.
:: One engine responded well to Shell V-Power, but there was little to choose between super fuels and ordinary petrol on economy and emissions.
:: Economy and performance were both slightly worse using BP Ultimate diesel, the super fuel furthest from the marketing claims.
:: Each super fuel had only a marginal effect on the emissions of measured pollutants, seemingly putting paid to environmental claims
:: There may be long-term benefits, but any break-even point in terms of reduced repair bills could take many years to reach.
A spokesman said: "For many cars it's a waste of money paying over the odds for so-called 'super-fuels'. The standard fuels we tested were all up to the job, whether from a major fuel brand or a supermarket."
© The Press Association 2008