Preheat oven to 300 degrees F. Grease 2 (8-inch) cake pans. Beat together sugar, oil and eggs. Sift flour, baking soda, cinnamon, and salt together. Add to sugar mixture alternately with carrots, raisins, and nuts, blend well.
Turn into your greased cake pans equally and bake for approx. 1hr 10min. Frost when cool.
Combine cream cheese, butter, confectioners' sugar, and vanilla. Beat on medium to high speed until mixture is light and fluffy.