Hot Weather Driveability and Vapor-Lock Performance with Alcohol-Gasoline Blends

The hot-weather driveability and vapor-lock performance of six vehicles were evaluated. Five fuels were tested: a base gasoline, base gasoline with Oxinol 50 at 3.5 weight percent oxygen, base gasoline with 8.2 percent methanol and 2.7 percent TBA (5 percent oxygen by weight), base gasoline with 3 percent methanol (1.5 percent oxygen by weight), and base gasoline with 7 percent methanol (3.5 percent oxygen by weight). Reid vapor pressure was matched for the driveability tests.

Overall, the hot-weather driveability and vapor-lock performance of the vehicles were good. As expected, the vapor-locking tendency of the carbureted vehicles increased with increasing RVP.