price of premium gas

I’m thinking of buying a new car this year, and I’m wondering if I should avoid getting another car that requires premium gas, because the price differential between regular and premium seems to be climbing. For you overseas dopers, where gas is really expensive, what is the current differential between 87 octane and 91 or 92?

In percentage terms the gap between regular and premium has never been smaller. In my area I typically see premium at c. 22 cents more than regular (with plus at 10 more). In the old days of low $1.00 prices, the gap was still 20 cents typically. Thus

Here in metro Atlanta, most stations have a pretty strict 10 cent price difference between grades – mid-grade is 10 cents more than regular, and premium is 10 cents more than mid-grade. However, over the last year or so, I have noticed a few stations (mostly Citgo) that have broken away from that rule; QT & RaceTrac (the leading independent/low-price stations in the area) follow the 10-cent rule pretty much 100% of the time.

In Iowa (and maybe some other midwestern states), most stations actually offer premium for less than regular – their premium fuel is a 10% ethanol blend, and the state/federal subsidies are passed on to the consumer.

Premium runs between 30 and 42 cents more than regular at the stations I see around here. (southwestern PA)

In other words, the price of upgrading from regular to premium for a, say, 20 gallon tank is about $4. Four bucks on top of a ($3.69/gal * 20gal) $73 fill up isn’t really much at all. That same upgrade is $4 when gas is $1.69/gal but it ‘feels’ much worse when your tab is only $34.

I don’t have any specific overseas numbers, but most countries outside the US and Canada figure octane ratings differently. They use one specific measurement, while US/CA use the average of the two measurements. So a European pump might give higher rating numbers than in the US.

Have you checked whether or not your car runs well on the other two types of gas? I have a minivan that gets better mileage out of economy.

It has a turbocharged engine, and the owner’s manual says to use premium, so I never tried anything else.

Around here, nearly all stations are still sticking to the ten cents per grade difference, no matter what the “base price” is for regular. There are a couple here and there that are doing eleven or twelve cents per grade, but for now, they’re fairly uncommon.

Is it tradition, or are the octane-raising ingredients really staying at the same price over the years, and the gas companies are passing along the actual costs without charging extra?

These days, it’s not generally added ingredients–it’s extra processing involved to increase the branching of the hydrocarbons.

Also, it’s a misnomer to refer to lower-octane gasoline as “economy” and higher-octane gasoline as “premium.” Increasing the octane of gasoline simply refers to decreasing the tendency for gasoline to pre-ignite. All grades of gasoline have the same additives, and have a negligible difference in energy content. In fact, there is no correlation between octane rating and energy content.

Higher octane gas simply has more processing associated with the refining process to produce gasoline that burns less readily to prevent pre-ignition. It is therefore more suitable for high-compression engines often found in higher-performance cars.

Using a higher-octane gasoline unnecessarily (i.e. if your vehicle’s manual does not specify its use) is a waste of money. There is absolutely no benefit whatsover to use a higher-octane gasoline if it is not needed. I really wish the fuel companies would knock if off with the “premium” label.

Here in Boston the gap is constant as well - 20 cents between 87 and 93 octane. Given how competitive the market for gas, I imagine it will stay that way.

Looking at just this part of the question, I would say that regular vs. premium fuel should be one of your least concerns. Sincre you didn’t give any driving data, I’ll make some assumptions for the calculations:
Lets’ say you drive 15,000 miles per year and average 18 miles per gallon. That’s 833.33 gallons of gasoline per year. At a 20 cent per gallon differential, you’re looking at $167 per year difference in total fuel cost. That’s about $3.21 per week. At current fuel prices you’d be much better off looking for a vehicle that is 2 miles per gallon more efficient than your current ride.

Whether it’s a splash of some additive or an extra bit of processing, has it really held steady to cost ten cents a gallon for all these years?

I have driven cars that required higher octane for over a decade, and the differential in pricing has always been about 10 cents between each grade.

Petrol isn’t really expensive here, yet, around $NZ1.80 a litre for unleaded 91 octane. ($US4.76 a gallon approx). 95 octane is 5 cents a litre dearer, and some places have 98 at another 5c a litre. Those 5c/l differences are pretty close to 13 US cents a gallon. (US gallon = 3.78 litres)

Here, 91 is regular, 95 is super and 98 is for those who have expensive Euro cars that turn their noses up at anything ‘common’ :wink:

Figuring just fuel costs per mile a car that requires premium would be roughly equal to one that gets one MPG less. This assumes the price difference is $.20 a gallon.

15,000 miles a year / 20 MPG = 750 Gallons X $3.20 = $2400

15,000 miles a year / 19 MPG = 789.47 gal X $3.00 = $2368