If you’re like most of us here at Jalopnik, you’ve probably wondered why gas stations offer mid-grade gasoline when almost every automaker recommends either regular or premium fuel. As it turns out, very few cars are designed to use mid-grade gas, so it exists mostly to coax unknowing consumers into spending more on gas, and it’s a relic from the days of leaded gasoline. To explain how, we have to look into the annals of history.
Cars used to run on leaded gasoline until the EPA began banning the use of it in new cars in the ’70s, and it stopped being available at gas pumps around the mid-1990s. During the transition from leaded to unleaded gasoline, most gas stations offered regular leaded gasoline, regular unleaded gasoline, and premium unleaded gasoline.
Once gas stations stopped offering toxic leaded gasoline at the pumps, the pumps still had an extra button, so companies started mixing premium and regular unleaded gasoline to produce a mid-grade. This was done in anticipation of automakers producing cars intended to run on mid-grade gasoline, however the automakers didn’t actually end up doing that., according to CNET,
Most refiners don’t really make midgrade gas. They make regular and premium and that’s what’s stocked underground at the gas station. When you squeeze the midgrade handle you get a cocktail of the two fuels, “splash blended” as you pump. Thank the EPA, because it tightened underground storage tank rules in 1988 and again in 2015, causing a lot of service stations to dig up and replace their old gas storage tanks. When they put new ones in they often installed just two and started to blend on the fly.
According to FuelEconomy.gov, the only new vehicles that are recommended to run on mid-grade fuel are Stellantis vehicles, including some Ram trucks, some V8 Chargers, Challengers, and 300s, some Durangos and some Jeeps.
Mid-grade fuel accounts for about seven percent of all gasoline sales, which means probably five or six percent of gasoline sales were unnecessarily upcharged. To the general public that isn’t car obsessed, it’s a fair logical assumption that the more expensive gasoline is better for your car, but putting high octane fuel in a car that’s not engineered to run on it doesn’t actually help your engine. Higher octane ratings mean that the fuel resists detonation longer, and allows higher compression engines to produce more power while being more efficient. If your vehicle isn’t designed to run on higher octane fuels, then filling it with a higher octane fuel won’t necessarily result in more power or economy since the grade of fuel doesn’t impact the engine’s programming.
For those car people who don’t understand why anyone would buy higher octane fuel thinking it’s higher quality, think about it this way, if you’re buying wine and you want something a bit nicer than Franzia, you look one shelf higher and find more expensive options that should be higher quality, and usually that’s true. So why wouldn’t the same concept apply to gasoline? Unfortunately, it doesn’t.
If your car does recommend mid-grade gasoline, it might be cheaper for you to make your own blend of regular gas and premium gas, since mid-grade gas is just mixed at the pump. A 50/50 split between regular and premium gas is the same as the mid-grade gas, so mixing five gallons of regular and five gallons of premium will be the same as 10 gallons of mid-grade, and you’re likely to save a few cents per gallon over using the pump-mixed mid-grade gasoline.
It seems like mid-grade fuel is still sold at pumps because ignorant consumers still buy it assuming they’re doing their car a favor, but they’re really just padding the wallets of the oil companies and gas stations. As always, read your vehicle’s owners manual or check inside your fuel filler door to make sure you’re not needlessly wasting money on more expensive fuel.