As we move closer to the fall/winter storage season consider that most parts of the country will be switching to "winter gasoline" blends sometime in the October to November time frame.
Winter gasolines have more high volatility components to aid cold starting, but the resulting higher Reid vapor pressure can increase percolation when next year's driving season begins. If you still have "winter gasoline" in your vintage Corvette when it gets hot next summer you will likely have increased percolation problems.
The switch to winter blend gasoline varies regionally, so you should do some research to find when the switch is required where you live. In California, winter blend is required from November 1 to March 1, and refineries begin to deliver winter blend in October.
It's a good idea to fill up on summer blend up to 30 days before winter blend is required to ensure that you're still getting the summer blend. Top off whatever you burn off before winter storage.
If you want to take a deep dive into the technological and regulatory framework of gasoline go to the following page:
Look at the right hand side and download the pdf "Motor Gasolines Technical Review".
You only need to read a far as the distillation profiles shown on page 2 to see why vintage cars are having percolation issues with ethanol-laced gasoline.
Duke
Winter gasolines have more high volatility components to aid cold starting, but the resulting higher Reid vapor pressure can increase percolation when next year's driving season begins. If you still have "winter gasoline" in your vintage Corvette when it gets hot next summer you will likely have increased percolation problems.
The switch to winter blend gasoline varies regionally, so you should do some research to find when the switch is required where you live. In California, winter blend is required from November 1 to March 1, and refineries begin to deliver winter blend in October.
It's a good idea to fill up on summer blend up to 30 days before winter blend is required to ensure that you're still getting the summer blend. Top off whatever you burn off before winter storage.
If you want to take a deep dive into the technological and regulatory framework of gasoline go to the following page:
Look at the right hand side and download the pdf "Motor Gasolines Technical Review".
You only need to read a far as the distillation profiles shown on page 2 to see why vintage cars are having percolation issues with ethanol-laced gasoline.
Duke
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