In a large saucepan, combine sugar and flour. Add the raisins, butter, vinegar and water; cook and stir over medium heat until thickened.
Line a 9-in. pie plate with bottom crust; trim pastry even with edge. Fill with raisin mixture. Roll out remaining pastry to fit top of pie. Place over filling. Trim, seal and flute edges. Cut slits in pastry.
Bake at 400° for about 45 minutes or until golden brown.