Quote Originally Posted by Pat Germain View Post
^^ Yup.

- All the gas stations in a given area get their fuel from the same distribution point. The only variable is the additives package and water is not among those additives.

- Any modern gasoline engine is designed to burn ethanol-blended gasoline. Running 100% gasoline won't hurt it, but it's not necessary.

- Alcohol is hydroscopic and tends to absorb more moisture from the air that pure gasoline. But as long as the fuel isn't sitting for months on end, it won't be a problem.

- Even 100% gasoline will start to go bad after a few months. Additives like Sta-Bil help, but not indefinitely.

- Seems almost every time I get gas, there's a fuel truck parked at the gas station. Never, not once, have I had a problem with getting gas while a fuel truck was filling tanks.

- The only way there is going to be a lot of water in the gasoline is if:

A: The tank is so leaky that ground water is getting in
B: The owner is putting a garden hose into the tank to stretch the gas

- I have a 1970 Mustang Mach 1 with the factory, carbureted engine. It requires premium gasoline because the engine has high compression (10.7:1). There is exactly one pump in my area that dispenses 100% premium gasoline. It's on the other side of town, it's unattended and it requires a commercial account to use. Not gonna go there. I've been running ethanol blended, premium gasoline in my Mustang for years with zero issues. I have replaced all the rubber fuel lines with modern, fuel injection hoses. Those are resistant to alcohol. No other mods are necessary.

- There is absolutely, positively no reason to run premium gasoline in a small engine unless you have modified said engine to have high compression; which is extremely unlikely. High compression, either from the combination of piston and combustion chamber or from supercharging or turbocharging, is the ONLY reason to use premium, high octane gasoline. Premium/high octane gasoline does not have any more energy than lower octane gasoline. It does not have a better additives package other than the additive which boosts the octane to make it less volatile. Putting premium/high octane gasoline into an engine which does not have high compression won't hurt anything other than your wallet. But it is a complete waste of money.
I agree but for one some item.
As someone who has built and rebuilt many, many engines, premium leaves a cleaner engine inside, IME.
Premium (whatever that is these days, 91, 93 ?) may cost more and do little for most engines, as you say, but a compression ratio in the high 10's or 11:1 is not that uncommon these days and some cars you might not expect can benefit.