Preheat oven to 350 degrees. Place pecans on baking sheet and toast in oven for 5 to 7 minutes, stirring half way through.
Prepare pasta according to package directions, cooking to al dente. Drain pasta and place in a large bowl.
In a medium bowl combine mayonnaise, sugar, red wine vinegar, red onion, and salt. Whisk well.
Add broccoli and grapes to the large bowl with pasta. Gradually add mayonnaise mixture (you may not want to add the whole amount).
Cover and chill for 3 hours. Stir bacon and pecans into salad just before serving.