how to barbecue a sirloin tip roast
1 Place the sirloin tip beef roast in a 1 gallon resealable bag. 2  Pour over the marinade to coat. 3  Marinate the roast for a minimum of four hours or overnight in a fridge. 4  Create a two-zone fire on your Char-Broil TRU-Infrared grill, turning one side of the grill on and leaving the other side off for indirect cooking. Remove the roast from the grill and increase the direct side of the grill to high. 2  Grill each side of the roast until the internal temperature is 120-130 degrees for rare. 3  Remove the roast from the grill and cover the roast with foil for 15 minutes.