Preheat oven to 350 degrees.
Coat the inside of a bundt pan well with butter or cooking spray. Sprinkle liberally with flour, turning the pan on it side and rotating to distribute flour evenly. The entire inside of the pan should be well coated.
In a large mixing bowl, combine cake and pudding mix. Add oil and water, mixing on a low speed just until combined. Increase mixer speed a little and add eggs, one at a time, allowing 2 minutes of mixing between each addition.
Struesel mixture: combine sugar, cinnamon and pecans in a small bowl; set aside.
Pour half of the batter into the bottom of the bundt pan. Sprinkle the struessel mixture over batter. Pour remaining batter into pan.
Bake at 350 degrees for 50-60 minutes or until cake is brown and set in the middle. Cake is done when a toothpick, inserted in the center, comes out clean.
Remove from oven and allow to cool 15 minutes. Use a very thin knife to gently release the outside edges of the cake from the pan. Place a serving dish over the top of the pan and invert quickly so the cake will drop onto the dish.
Allow to cool completely.
A powdered sugar frosting or glaze may be drizzled oner the cake, if desired.