Drivers forking out for high-end petrol in the hope of saving money may be better off sticking to the cheap, or at least cheaper stuff, a new study suggests.
The results of tests conducted by driving lobby group AA are to be published in its magazine Directions this week.
It compared 98 octane petrol, often dubbed "super", with 95 octane "premium" on a high performance car which travelled on 15 litres of each petrol.
While economy improved, the 2011 Subaru Impreza WRX drove only another 1km on super grade than premium, AA principal adviser Mark Stockdale said.
Based on the AA's assumption that the "average" driver travels 14,000km a year, the higher cost of super grade meant it cost another $83.67 a year to run.
A second test saw a car designed to use regular 91 octane fuel - a 1.5 litre 2010 Suzuki Swift - run as far as it could on 15 litres of regular grade, before repeating the test on premium 95 grade.
Mr Stockdale said the Suzuki's economy improved when using premium fuel, travelling 9km further. However, the added cost of premium meant that over the course of a year, a driver would end up paying another $6.86 than if they used regular grade.
BP spokesman Jonty Mills said the results for its super premium - which it markets as "ultimate" - were "outstanding" for the luxury grade which it promoted for performance, not economic, reasons.
"We don't make any claims about its economic benefits, it's about the best quality fuels to maximise the car's performance", such as reduced engine wear.
"Using this one example, we think $84 a year is perfectly reasonable."
The AA made no attempt to compare performance attributes between the fuels, but used the results to call for stations to clearly state what fuel is sold where.
BP sells 98 octane fuel at 99 of its 280 retail sites, while Mobil sells it at 31 North Island sites.
But for motorists it is often unclear which fuel is sold until they are at the pump because only the price of regular petrol is advertised on station hoardings.
The AA is also seeking a law change to assist car buyers.
Currently dealers are forced to tell buyers whether a car's FM stereo will work in New Zealand, but not what kind of fuel it is recommended to run on.
The AA says it has anecdotal evidence that second-hand importers often recommend ‘you can't go wrong with premium'.
It wants dealers to be forced to find out the recommended grade before selling a car.
- The Dominion Post
Subscribe to a digital replica of The Southland Times.
Southland Times subscriber news and information.
Click here for information about advertising with The Southland Times.