1. Preheat oven to 350°. Bake pecans in a single layer in a shallow pan 5 to 7 minutes or until lightly toasted and fragrant, stirring halfway through.
2. Prepare pasta according to package directions.
3. Meanwhile, cut broccoli florets from stems, and separate florets into small pieces using tip of a paring knife. Peel away tough outer layer of stems, and finely chop stems.
4. Whisk together mayonnaise and next 4 ingredients in a large bowl; add broccoli, hot cooked pasta, and grapes, and stir to coat. Cover and chill 3 hours. Stir bacon and pecans into salad just before serving.