A computer model of fuel evaporation in an idealized intake system is used to study the effect of engine speed on air-fuel mixture temperatures. The model allows for multi-component fuels present both as entrained droplets and wall films. Data are presented showing the relative importance of a range of parameters including: fuel composition, air speed, and droplet size and distribution. Computer predictions are compared with empirical data gathered using various methanol-gasoline blends on a test-rig. Model predictions are found to correlate significantly with measured film and droplet temperature data.