Why do higher elevations have lower octane?

Air is less dense at higher altitudes than it is at sea level so when it is compressed in engine cylinders the pressure is proportionately less. The result is equivalent to having a lower compression ratio. Reduced compression pressure = reduced octane requirement.

Do you need higher octane fuel at higher altitudes?

A: At higher altitudes, the air is thinner so you can actually get by with a lower octane gasoline. For instance, regular grade fuel is 87 octane in Chicago, but 85 octane in Denver. Your car will adjust itself for any elevation.

Can you use lower octane fuel at higher altitudes?

A: Nearly all cars can run on a lower octane at high elevations. The lower octane fuel (usually regular grade) is usually 100 percent gasoline, no ethanol. It is popular in the West, especially the high plains where the air is thinner (oxygen content).

Why is Colorado gas lower octane?

According to this article from AAA, the stated reason is that most of Colorado is at high elevation, above 5000 feet (about 1500 meters), and the thinner air tends to prevent detonation. Therefore, in theory, one can use the cheaper, lower octane fuel without problems, and save some money.

Why is gas 85 octane in Colorado?

Octane Ratings At Altitude Because the air is less dense, less air flows to your car’s engine. This translates to a slightly richer air-fuel ratio, and deters engine knock. For that reason, you’ll find that regular gas carries an 85 octane rating here in Denver and throughout Colorado, Wyoming, Utah and Montana.

Does California have 93 octane?

Registered. California gas stations sell only 91 octane gas, not 93, but there are a few stations that sell ethanol-free 100 octane racing gas.

Why vehicles consume more fuel at high altitudes?

Due to the decrease in the air pressure and oxygen density with the increasing altitudes, the diesel engine combustion deteriorates and results in decreased thermal efficiency, reduced power output, and increased fuel consumption,6–10 especially in comparison with the engine operation at near sea level.

Can I use e88 gas instead of 87?

Turns out, some car owners should steer away from using it, even though it can be cheaper than the standard 87 octane fuel that is 10 percent ethanol. The 88 octane should have no effect if you happened to fill you tank with it once, but prolonged use by a car not equipped for it can cause an engine to wear out faster.

What does E85 stand for?

flex fuel
E85 (or flex fuel) is a term that refers to high-level ethanol-gasoline blends containing 51\% to 83\% ethanol, depending on geography and season (see Fuel Properties and E85 Flex Fuel Specification).