By Samuel Smith
Published: Thursday, February 28, 2019
Updated: March 1, 2019 at 2:41 pm
South Australians have some strong opinions about where to fill up and what’s in their fuel, according to RAA’s latest Fuel Survey Report.
But is BP fuel really of a higher quality? Can using e10 damage your car? Does premium fuel get you further?
Here, we bust a few myths about big-name petrol brands and give you the lowdown on what’s in your fuel, from 91 octane to ethanol.
Where we’re filling up and why
Close to a quarter (23%) of respondents surveyed said they used a Caltex Woolworths service station the last time they refuelled.
Liberty, BP and On the Run fuel outlets were visited by more than 10% of respondents for their last fuel purchase, with Costco, Mobil and Mogas being the least frequented. Less than 4% of respondents visited these outlets for their last fuel purchase.
The reason why could be tied up in our perceptions – for 20% of respondents, Costco fuel was perceived as the lowest quality.
Close to half (46.7%) rated BP fuel as above average quality and 40.7% of respondents rated Caltex Woolworths fuel as the same.
OTR and Coles Express fuel received above average quality ratings by 37.4% and 35.0% of respondents, respectively.
On the lower end of the scale, only 33% of respondents rated fuel from small independent brands as above average quality.
Is all fuel equal?
Contrary to the results of our fuel survey, RAA Future Mobility Expert Mark Borlace says fuel is fuel, as it all has to comply with the same quality standards.
“It’s all the same chicken; each brand just sprinkles it with their own secret herbs and spices,” he says.
Fried chicken analogies aside, Mr Borlace dispels the myth that one brand is better than another.
“There’s really no logical reason to choose one brand over another,” he says.
Mr Borlace goes on to explain that essentially, most fuel comes from the same place, so at the end of the day, you’re paying more for the brand name.
“The only difference is that some [brands] will put different additives in their fuel – none of which will have much noticeable difference on your car’s engine or performance.”
Fuel types explained
We’ve established that brand makes little difference to a fuel’s quality, but regardless of where you fill up, you’ll find a variety of different fuel types to choose from. It’s important to know what’s in each type so you can pick what’s best for your car.
Unleaded petrol is a lead-free gasoline mixture. Unleaded fuel is rated by its RON (research octane number), which measures the petrol’s anti-knock quality (the tendency of the fuel to detonate instead of burn smoothly). 91 octane fuel has a comparatively low anti-knock quality, whereas higher octane fuels such as 95 and 98 allow engines to run at a higher compression level.
- Unleaded 91 octane: This is the cheapest unleaded fuel available. If the inside of your petrol cap reads ‘unleaded petrol only’, you can use 91 octane fuel. If it reads ‘premium unleaded only’, you’ll need to use 95 or 98 octane fuel. You can use an octane number that’s higher than recommended, but using a lower octane fuel could cause engine damage.
- Unleaded 95 octane: Also known as premium unleaded, 95 octane should be used in vehicles that require ‘premium unleaded only’. Though you’ll be paying a higher price, 95 octane fuel contains slightly more energy than 91 octane fuel so could provide a very small increase in fuel economy, but nothing noticeable. That being said, there is no need to use 95 octane fuel in a car that only requires 91.
- Unleaded 98 octane: This is the highest rated unleaded petrol available, offering maximum protection from detonation. 98 octane fuel has a high price, but is essential for most performance vehicles. It goes without saying, if your car has a ‘98 octane only’ sticker on the inside of its petrol cap, you should only use 98 octane fuel. If your car is designed to run on a lower octane fuel, you won’t notice much difference when filling up with 98. It’s unlikely to improve your car’s perform, fuel economy, or emissions.
E10 is a blend of ethanol and unleaded petrol. Ethanol is a natural alternative to unleaded petrol, made from renewable sources such as sugar, starch and cellulose. Most cars built after the year 2000 can run on E10 fuel, and although it is usually slightly cheaper than 91 octane fuel, it contains less energy so you will use more fuel. Cars can emit around 7% less greenhouse gasses when using E10 fuel.
E10 fuel will not negatively affect most cars built after the year 2000, but it’s important you find out if your car can operate on E10 before you fill up. Filling up a car with E10 that isn’t compatible could result in damage to the fuel system and catalytic converters.
Although diesel fuel starts off as the same crude oil mixture as petrol, it is heavier, oilier and evaporates much more slowly. Diesel takes less refining to produce than petrol, which is why it was once so much cheaper.
Now, due to supply and demand, it costs slightly more at the pump than petrol. Diesel fuel can only be used in diesel engines and can result in more pollutants than other fuels.
LPG is a mixture of propane and butane and is far cheaper and cleaner than petrol. LPG can only be used in LPG-specific or LPG-converted cars.