how long should i bbq a 2.5 pound tritip?

Answer 1

There is a special secret to keeping your tri-tip moist and delicious on the grill. Double-wrap the tri-tip in foild, sealing the edges well. Put foil-covered tri-tip on the top rack of the grill on high heat for 40 minutes. Remove from grill. Open foil packet over a clean baking dish and drain out all the meat juices (liquid gold!!!). Put the tri-tip back on the grill without the foil (fat side down). Cook for an additional 7 minutes on each side.

Answer 2

Did you want it 'dead n' red' or no red meat at all?

Between 45min- 1hr and 30min depending on how red/dead you want it and what you are cooking it on.