How big a 2-by willI need to support a drop ceiling?

I'm installing a new garage door on my shop. The old door is a slab door that pivots and does not intrude into the shop. The new door will retract into the shop. The ceiling in the garage is a drop ceiling with shop lights attached. I'd like to have the garage door go above the ceiling, To do this I'll need to support the ceiling away from the front wall. I'm planning on supporting with a 2-by from a pair of steel hangers set back from the front wall 24". The span is 16 feet between the steel hangers can I get away with a 2x4 or will I need a 2x6?