As gas sits around, parts of it evaporate and can escape the fuel container–and we say “parts of it” because gasoline is a fairly complex substance.
Gasoline is made up of aliphatic and aromatic hydrocarbons–let’s call them open chains and closed rings. The light ends, technically known as short-chain aliphatic hydrocarbons, evaporate first, leaving behind the long-chain aliphatic and aromatic hydrocarbons.
You don’t need to own a lab coat to understand the results: A fuel that’s light on short-chain hydrocarbons is harder to ignite because it needs a higher temperature to vaporize enough fuel to support combustion, explains Zachary J. Santner, technical specialist at Sunoco Race Fuels.
Subscribe now to read the rest in the November issue of Grassroots Motorsports Magazine.
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