Blower Speed

[TyMech]

I have a Coleman Model EB17B Serial #040112002 from what i can read this is a popular unit among mobile homes ours is in a double wide so it has the 16x6 duct board and a 8 inch round flex duct connecting the other side i was reading a post recently about this unit being capable of upgrading to a five ton blower for more cfm the blower side of the house blows fairly decent but the other side is weak i think this is due to not enough cfm. both inside and outside units were replaced two years ago all coils and filters clean is the upgraded blower an option i believe this is a multi speed blower it has a blue black yellow wires running from it with black being high speed hooked up. our house on a 105 degree day gets to 85 degrees with an outragous electricity bill do we have options?

[DaleM]

The 8" flex duct is too small. You should have a 12" duct for that.