Heat oven to 350°F. Grease and flour two 8x4 or 9x5-inch loaf pans. In large bowl, combine sugar, water, oil, eggs and sweet potatoes; blend well.
In medium bowl, combine flour, baking soda, salt, cinnamon and baking powder; mix well. Add to sweet potato mixture; stir just until dry ingredients are moistened. Stir in pecans. Pour into greased and floured pans.
Bake at 350°F. for 60 to 70 minutes or until toothpick inserted in center comes out clean. Cool 15 minutes; remove from pans. Cool 1 hour or until completely cooled. Wrap tightly and store in refrigerator.