[JimGnitecki]

Obviously, gasoline octane rating is rather important for forced induction engines.

But gasoline octane apparently degrades as gasoline sits in storage in a car's fuel tank.

A 2018 article by a technical specialist at Sunoco Race Fuels says in part:

"87 octane fuels tend to be less refined and contain more unstable hydrocarbons. As the months pass during storage these unstable components react to form gums, varnishes and lower octane hydrocarbons. As a result the octane can decrease within months for 87 octane fuels, especially when stored under less than ideal conditions. 93 octane fuels are more refined and contain more stable hydrocarbons. These stable hydrocarbons can last 2-3 times longer than 87 octane fuel. Even in proper storage 87 octane gas can start to degrade in 3 months, 93 octane fuel should last closer to 9 months before degradation is noticeable. Keep in mind that 93 octane fuels are still susceptible to octane loss and vapor pressure decreases due to butane evaporation."

Here in the Province of Alberta, in Canada, we had an unusually (record even) cold, icy, and road-salted time period in November and December, that made driving my Magnuson supercharged LT1 impractical. So, basically, my Camaro has not been driven, except twice for a few kilometers each time, since Halloween, 2-1/2 months ago. The car was last refueled with 91 octane gasoline (the highest octane locally available) around Halloween.

I realize that the Sunoco tech article seems to say that high octane fuel MIGHT not degrade for as long as 9 months. But am I correct in thinking that when the current persistent icy period ends, it might be unwise to use a lot of throttle until the "old" gas in the tank gets used up and replaced by new fuel? Or, is there a safe additive that can be added to the tank to alleviate any octane concerns?

For what it's worth, the car has been stored in a garage where temperature has been relatively stable, most of the time remaining at about 8 degrees C = 46 degrees F, but once getting as low as +2C = 36F when the temperature outside hit -32C = -26F!

Jim G