Streams

Confusion at the Gas Pump: Which Grade is Best?

Tuesday, December 11, 2012 - 02:07 PM

Octane ratings at a California gas station, 2007 (photo by f31fud via flickr)

(Isabel Angell -- San Francisco, KALW) Gas prices in California are always a big problem. And this year, the average price per gallon is set to hit four dollars – the highest average ever. It seems like there’s nothing the average driver can do to lower their fuel costs – except, maybe, change what grade of gasoline they buy. Most people, though, have no idea what that means for their car.

A choice at the pump

At a gas station in El Cerrito, people pull up in their cars to fill up their tanks. At some point, each of them presses a button: regular, mid-grade, or premium. The higher the grade, the higher the octane content. And the higher the octane content, the higher the price. At this gas station, regular gasoline costs $3.82 per gallon and premium costs $4.05 – twenty-two cents more expensive. I’m curious, so I start asking people what kind of gas they’re buying, and why.

Kate Foley buys gets regular because it’s the cheapest, she tells me with a laugh.

Susie Marcus went for the regular unleaded, “I guess because it’s the least expensive and I have not seen any proof that buying the better gas makes you go farther or better mileage.”

Ariana Jones sprung for the premium. She tells me it’s the only kind her car will take.

So, how are they making these decisions? If it’s just based on price, there’s no reason to use premium, unless the more expensive gas is actually better.

For answers, I turned to Daniel Kammen, a professor at the Energy and Resources Group at UC Berkeley. He told me octane is a measure of energy content. So the different grades of gas have different energy contents. I asked him what that means for my car.

“You get more zip in the car when you use a fuel with a higher energy content,” says Kammen.

But before you start imagining your humble Honda Civic transforming into a fiery red Mustang, a word of warning from Kammen: “There's very little difference in everyday behavior. So if you're doing urban driving, you’re not going to notice much difference because you're not going at the speeds when it matters. And on the highway you have to have a really high performance car to really see that difference.”

And by high performance car, he doesn’t mean a lowly BMW.

“You most likely see it when you start driving Lamborghinis and Ferraris,” says Kammen.

The latest numbers from the California Energy Commission say that 18 percent of gas sold in California in 2010 was premium. But 18 percent of Californians probably don’t own a Lamborghini.

So why do people buy premium when they don’t have to? I asked Sudhot Bhat, who teaches marketing strategy at San Francisco State. He says that most consumers are not experts in the things that they buy.

“Even for things like toothpaste, they are not very good judges of quality,” Bhat says. “So what I sometimes think is that a lot of consumers use price as a gauge of quality. If they do not know much about a product, they tend to think that the product with the higher price is higher quality.”

Bhat says because most people don’t know what’s going on in their gas tank, some consumers might spring for the premium gas just because it’s more expensive. But he has a solution for people who want to get the most bang for their buck: look it up on the internet.

“I think if consumers had more time and they did some research, they would know what really is good quality. You don't have to take the manufacturer's word for it, you can actually go on see what other people are saying,” says Bhat.

One of the big reasons people say they like to buy premium is to prevent engine knocking, when the fuel doesn’t explode the right way in the engine, and that makes a knocking sound. It means you’re not getting the full power of the gas – and if it keeps happening, it can actually hurt your car. But, for the last fifteen years or so, engines have been built with sensors to prevent this exact thing from happening.

So what should you be buying? I took Sudhot Bhat’s advice and turned to the Internet. What I found matched what Berkeley’s Dan Kammen told me: if your car’s manual says it runs on regular, there’s no reason to splurge on a higher grade. And many high-performance cars will run on regular – you just might not get the maximum power possible. Turbo-charged really do require the high-octane premium, so check with your mechanic before making the switch.

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Comments [2]

Dan

I had a 2002 Miata from 2005 to 2008. The cas cap door said "premium preferred". If I ran it on regular mileage dropped by about 10%. Since premium was 6% more money I put in premium. But I would never buy premium for a car designed for regular.

In 2008 my daughter and I drove from LA to Pittsburgh in a "new for her" 2005 Chevy Cavalier and we worried not in the least about gas being over $4.50 a gallon at the time. We needed it and since we still spent no more on gas than we did for motels, it was just something we did. The cost is no big deal until it gets to $10 plus. I live in Vancouver BC now and we pay about $5.50 a gallon and it does not affect how much we drive up here in the least.

Jan. 07 2013 11:54 AM
Tom

I remember buying regular outside Yosemite Park for $4.59/gallon in 2008, and this was before the 'spike'.
I, and everyone else, bought just enough to make it to the Interstate at Merced where the price dropped precipitously.
Where & when, time & place utility, counts.

Dec. 12 2012 05:14 PM

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