Why Is There 85 Octane Gas In Colorado?
October 21, 2020
I finally got around to looking up why regular gas in Colorado is 85 octane and not the 87 octane on the east coast. The following article is from the Denver Post in 2006:
With Colorado gasoline prices down 70 cents from a record high of $3.08 per gallon of regular unleaded in August, what’s left for consumers to complain about?
Octane levels, that’s what.
The arcane topic of octane isn’t on everybody’s radar screen, but for those attuned to the little yellow stickers with black numbers on the gas pump, it can be a big pet peeve.
The issue: Regular-grade gasoline in Colorado is 85 octane. In most of the rest of the country, regular is 87 octane. To get 87 in Colorado, motorists have to buy midgrade, which costs on average $2.54 a gallon, 16 cents more than regular. The nationwide average for 87 octane is $2.36.
“If I put 85 octane in my cars, they just knock like crazy,” said Ted Kinsman, a corporate financial trainer from Crestone. “I don’t really understand how we in Colorado can consistently operate on 85.”
Kinsman and other octane observers can take heart that a national standards body that recommends octane levels is set to discuss Colorado’s minimum octane in a December meeting.
But until that possible change, why is Colorado stuck with 85? And just what the heck is octane, anyway?
Octane is an index number that measures a gasoline’s ability to resist engine knocking.
American refineries produce gasoline with octane levels ranging from 85 to 94. The lower the octane level in gasoline, the less expensive it is for refiners to produce.
Colorado and several other Rocky Mountain states have minimum octane levels of 85 for regular gas, while most states with lower elevations have a minimum level of 87.
Research several years ago from the American Petroleum Institute showed that lower air pressure at higher altitudes allows vehicles to perform as well with 85 octane as they would with 87 at lower altitudes.
But a 2001 study by the Colorado Legislative Council, the state legislature’s research arm, concluded that the altitude difference may apply only to older cars.
“Research findings indicate that newer vehicles manufactured in and after 1984 are equipped with sophisticated electronic control systems that minimize this altitude effect and may perform better using higher-octane gasolines,” the report said.
So why does Colorado still have 85 octane in regular gas, even if most cars are better suited to 87?
The wheels turn slowly in the world of octane.
Colorado’s 85 octane standard was set decades ago based on a recommendation by ASTM International, a body that establishes standards for everything from detergents to paving materials to gasoline octanes.
Petroleum industry officials and state regulators say that for years they’ve gotten periodic complaints or inquiries from the public about octane.
But it was only last week that ASTM International officials determined that the newer automotive technologies that apparently have rendered 85 octane less useful warranted a discussion about possible changes in Colorado.
Many car manufacturers recommend that motorists use at least 87 octane.
“They used to put in fine print that 85 octane was acceptable at higher altitudes, but mostly the manufacturers no longer agree with that,” said Dick Piper, director of Colorado’s Division of Oil and Public Safety.
Yet Colorado motorists continue to show an overwhelming preference for regular- grade gas, even at 85 octane.
In the first half of 2006, 80 percent of Colorado’s 35 million gallons in gas sales was regular, according to the U.S. Energy Information Administration. Midgrade at 87 octane accounted for 9.5 percent of sales; premium at 91 octane represented 10.5 percent of sales.
“Sales of midgrade and premium have declined over the past few years as consumers have traded down octane levels in reaction to escalating gasoline prices,” said Jeff Lenard of the National Association of Convenience Stores.
Denver motorist Jason Sullivan said that although his 2004 Toyota Corolla specifies 87 octane, he’ll follow many experts’ recommendations to use the lowest octane available as long as the level doesn’t cause engine knocking or poor performance.
“It’s tough enough to fill this thing up even at regular (grade) prices,” he said last week while pumping 85 octane. “Until my car starts complaining, I’m going to stick with the cheaper stuff.”