I fill up when I get 145 on the tankful and typically use 3.1 to 3.2 gallons to refill. My light doesn't come on typically until I have 150+. I use premium grade fuel and add about 1/2 ounce of acetone which helps keep the alcohol in suspension and breaks down the surface tension of the fuel to vaporize/burn better. I do this for all my vehicles 1 oz. per 10 gallons of gasoline.
SEMPER FI2010 Vegas 8 Ball