Fred482
ArboristSite Operative
Ethanol octane ratings vary but most users say it's in the range of 110-113, pure racing grade methanol can be as high as 120. Methanol has a higher latent heat of vaporization, thus provides more cooling during the evaporative process. If run rich, 5.5:1 AFR, it can support compression ratios of up to 20:1.
Corrosion issues aside, the key to making parts live in a race engine is heat, if it runs rich on methanol, the parts stay cool enough to survive. The down side is, when rich enough to save all the parts, it becomes hard to get it to burn.
I used to measure the cylinder head temps (5 HP Briggs Motor Sports block, aftermarket head and internals, Tillotson carb, straight methanol fuel) before and after a run with my daughter's junior dragster and found them at 125 degrees F at the start and just over 200 F at the finish line. Gasoline temps were higher, 185 F at the start and near 310 F at the finish. This with the carburetor adjusted for best performance.
Corrosion issues aside, the key to making parts live in a race engine is heat, if it runs rich on methanol, the parts stay cool enough to survive. The down side is, when rich enough to save all the parts, it becomes hard to get it to burn.
I used to measure the cylinder head temps (5 HP Briggs Motor Sports block, aftermarket head and internals, Tillotson carb, straight methanol fuel) before and after a run with my daughter's junior dragster and found them at 125 degrees F at the start and just over 200 F at the finish line. Gasoline temps were higher, 185 F at the start and near 310 F at the finish. This with the carburetor adjusted for best performance.