Is Costco Premium Gas 91 or 93 octane? (And does it even matter?) – Jalopnik

We need to separate the chemical ‘octane’ from the ‘octane number’ of a fuel because these can be two different things. Think about it this way. If you learned your shapes in kindergarten, you can easily remember this rule: all squares are rectangles, but not all rectangles are squares. Now let’s apply this maxim to the chemistry of gasoline: all octane compounds increase octane, but not all compounds that increase octane are actually made of octane.

An example of this is that both ferrocene and ethanol will increase ratings but won’t show up at octane family reunions. Lead will also do the job, but has a few drawbacks, including behavioral, learning, growth, reproductive, cognitive, hearing, memory, muscle and joint problems.

And this is why we care about octane. Most cars live on a “normal” diet of 87 octane, but high compression or forced induction (turbocharged or supercharged) engines require an octane rating closer to triple digits. High pressure and heat in these tightly compressed combustion chambers ignite low-octane fuel unevenly, resulting in detonation (bad for you, great for a mechanic financing his children’s college).

So when you drive your Bugatti Chiron (or any other high-performance or luxury car) into a Costco gas station, use 93 octane to spur all of the car’s 1,479 horses into action. Smile for photos, too, as Bugatti sightings at Costco stations are likely rare. But if you fuel your quad-turbo W16 warp drive with 91 octane, the engine will limit itself to a paltry 1,200 horsepower to avoid damaging explosions.

Now, CostcoThe FAQ page states that fuel ratings are “typically 87 octane for regular and 91 octane for premium gasoline.” The word “typical” is a problem for you Chiron owners, because you need to research which Costco gas stations with extra-long hoses can unleash all 1,479 ponies.

Life would be just that much better if Costco’s website listed which of its stations would offer the higher premium, but unfortunately that’s not the case. Costco’s site does show which US states have Costco warehouses and how many there are (606 at the time of writing), although not all warehouses sell gas (only about 67%). Simply finding a list of all Costco gas stations (or Kirkland, the brand Costco uses for its fuel) is a maddening undertaking. Your best bet is to use Costco’s warehouse directory to find nearby stations and call them if your engine really needs premium gasoline.

Even determining which states offer widespread 93 octane is difficult. According to find93.comdocumenting user-reported observations of 93 octane, 46 states sell 93. Take this list with a grain of salt, though, because California is also on it, and that state will not sell you 93 octane for street use. To understand why, simply turn back time to October 2001 and navigate to Autoweek.com on your beige Compaq Presario to enjoy a new article titled “No More 92: Premium Octane Rating Drops in California.”

The article reports that Governor Gray Davis banned the octane-boosting and carcinogenic methyl tertiary butyl ether (MTBE) in 1999, but the only real alternatives were using ethanol, which could not be added in the same proportions as MTBE, lowering the octane number to 91, or applying Unocal’s MTBE/ethanol-free, patented process for creating 92 octane, which would have meant licensing fees. for refineries. Ethanol clearly won, as evidenced by the fact that in 2001 about 1 billion bushels of corn went to ethanol production, and in 2010 that figure shot up to 5 billion bushels. More than 20 years later, 91 still reigns supreme and there is no 93 at the average California gas station.

In some states, such as Florida or Virginia, the top range may be 93 or 91 depending on the station. If you go for a Wawa in the 91/93 state, you might find them both at the same pump, but Costco only offers “regular and premium gasoline and diesel in select locations,” so you’ll never find a mid-range or other 89 octane options there. At Costco you get two choices, and if the top choice is 91, then that’s what you get. You might even find an octane rating of 92 feels like it’s California in the 1990s.

And 91 isn’t even the worst high-octane choice, as Alaska doesn’t sell anything with a higher octane rating than 90, which is below the bare minimum for premium as defined by the U.S. Energy Information Administration. Don’t bother calling any of the three Alaska Costco Warehouse locations with gas pumps—their high-mid 90-octane range won’t get your Chiron up to its reduced 1,200 horsepower. Maybe just rent a car from Costco and leave the Chiron at home.

If you’re reluctant to call your local Costco for octane levels, know that Yelp contributors often take photos of the pumps. The first photo in the Yelp review for Hoover, Alabama’s Costco clearly shows a button for 93 octane. After you’re done looking at the photos, enjoy strangely glowing reviews of the gas station atmosphere, like Laura S’s comment, “I love the gas station attendants! They’re always so super nice and love to chat!”

If you want to know where you can get 93 octane and have a good conversation about how much your favorite college football team disappointed you last weekend, this is where. Just don’t bring your Bugatti Chiron, otherwise the conversation will be constantly interrupted by looky-loos.