I run a 50/50 mix of 110 Turbo Blue and 90 octane “Rec” fuel with no ethanol. That technically gives me about 100 octane leaded gas. It’s $10/gal for 110 and $6/gal for rec fuel, netting $8/gal. But in fairness, my car has never seen ethanol fuel, and runs very well on that mix. When I have to hit the rec fuel first when I get low, the car does not run as well, but it’s about 15 minutes up to the station that sells the 110.
My understanding is that octane slows the burn of gas, allowing for a hotter burn, which these old cast iron engines were designed to run on. The ethanol raises the octane rating a couple points, so what you’re really running is 85 octane clear gas with an alcohol mix to boost the octane. It fires quicker but not as hot for as long, and cast iron engines don’t like that.
My understanding is that octane slows the burn of gas, allowing for a hotter burn, which these old cast iron engines were designed to run on. The ethanol raises the octane rating a couple points, so what you’re really running is 85 octane clear gas with an alcohol mix to boost the octane. It fires quicker but not as hot for as long, and cast iron engines don’t like that.
