Arrange pecans on a baking sheet in a single layer and toast them in the oven for 7-9 minutes, until golden brown and aromatic.
Reserve 1/2 cup of the toasted pecans for the topping.
Grease two 9 x 5 inch loaf pans or 36 standard-size muffin cups with butter or cooking spray.
Whisk the oil and sugar in a big bowl; add in eggs, pumpkin, and water; whisk until combined.
Stir in the flour, baking soda, spices, and salt; gently stir in 1 cup of the pecan pieces.
Pour half the batter into each loaf pan (for muffins, fill muffin pans almost to the top with batter).
Topping: Stir the sugar, butter, cinnamon, and the reserved 1/2 cup of pecan pieces in a bowl; sprinkle the topping liberally over the loaves or the muffins before baking.
Bake the loaves for 1 hour, or until a pick comes out clean; bake the muffins for 30-35 minutes.
**May substitute 1 cup of whole wheat pastry flour for 1 cup of all-purpose flour.