Which Fuel Drives Your Dollar Further? | Auto Expert John Cadogan | Australia

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• published: 09 Apr 2016
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Full report: http://autoexpert.com.au/buying-a-car/fuel-watch-which-fuel-drives-your-dollar-further You’re parked on the filling station forecourt: You want some cheap fuel. There are four different flavours of petrol - and four different petrol prices. It’s the ultimate grudge purchase: if you don’t buy petrol, your car becomes furniture - at best, a modern art masterpiece. You’re face to face with the fundamental first-world dilemma: Which petrol is really cheapest? Which fuel drives your dollar further? Let’s find out. Our way of life revolves around petrol prices. We are all fuel watchers, to some degree. Fuel consumption is one of modern life’s most fundamental exchanges: Money in exchange for miles - cash for kilometres, for the metrically minded. People obsess about petrol prices. Which is why I got a call from the news director at Channel 7 in Sydney the other day - Australia’s premier TV news network - he said: “Do you want to figure out petrol prices?” I said: “OK.” The back-story on petrol prices You, presumably, are a human being. Me too (more or less). In the modern world, we’re on top. And I like being on top. A lot. But we are not on top because of our big brains. Dolphins have big brains, and yet they end up in our tinned tuna. So that’s not it. We’re on top because we burn. It's all about fuel consumption - access to cheap fuel. Global superiority is all thermodynamics. We burn considerably more energy from cheap fuel than we derive from our food. We are the only species on earth that does this. Fuel consumption - access to cheap fuel - puts us on top. You enjoy unprecedented mobility as a direct consequence of fuel consumption: us taking ‘fire’ to the next level. It's all about access to cheap fuel. Seriously. Think about it. You have, today, the kind of mobility that a Roman Emperor or an Egyptian Pharaoh could only dream about after snorting the best drugs. It’s a lot of fun to burn cheap fuel. But I bet you don’t jump out of bed each morning, do a quick 'fuel watch' assessment, confirm your species' position (still on top) and riff a bit of air guitar because cheap fuel makes you more mobile than Tutankhamun could ever hope to be. I bet instead you bitch about petrol prices … you ungrateful asshole. The petrol prices test: who, what & how Here’s what we did with fuel consumption and petrol prices, plus how we did it, and what it means. First up: the car. New Hyundai Elantra. 2.0 multi-point injected petrol auto. Hyundai whipped up Pete - red-hot technician - and Pete whipped in a special fuel tank, and that allowed us to eliminate all kinds of fuel consumption uncertainty. We could do low-volume, controlled, repeatable petrol re-fills: dead easy. And, to boost our fuel consumption experimental controls, we used a controlled one-kilometre track at the Western Sydney International Dragway, and another secret weapon: Ian Luff - the Luff Man - Australia’s pre-eminent advanced driver trainer. He plonked himself in the Elantra and drove like a fuel consumption robot - a robot with Miss Daisy in the passenger’s seat. I take an average of the respective petrol prices and I work out how much petrol one Aussie dollar buys of each of the four fuels - a minimum of 740 ml of 98 octane premium and a maximum of 870 ml of e10. We prime up the lines with the target fuel, run the car to get that fuel all the way into the engine, shut down, pump all the residual fuel out of the special tank, tip in the carefully measured control volume of the required test fuel, zero the trip meter, and then the Luff robot takes over, and drives until … dry tank; dead silence. We note the distance and go again … times four fuels. The fuel consumption results lined up pretty well with the theory. Premium 98 delivered the best fuel consumption (in terms of the volume burned per distance driven), followed by premium 95, regular 91 and e10 fuel with the highest consumption - and that’s exactly what established combustion theory tells us to expect. So: No nasty little surprises there. But this wasn’t a test of that thermodynamic theory - it was really all about the economic rationality underpinning fuel consumption. It gets interesting when you factor in the price. Regular unleaded fuel - the 91 octane stuff - took us the furthest on $1.00 in fuel. Premium 98 octane operated at an 11 per cent fuel consumption disadvantage - at least in terms of how far every dollar takes you. Premium 95 octane was eight per cent behind the eight ball and e10 fuel lags by about four-and-a-half per cent. But if all you care about is the cost of getting from A to B, it’s fair to say oil companies are grossly overstating the purported benefits of putting premium petrol in average vehicles. Sure - there's a slight improvement in fuel consumption, but it's way more than eclipsed by the fuel price itself. They just want you to buy premium petrol because it pumps up their profits, while delivering almost no tangible benefit to you.