What HD projectors have a 80" screen at about 13 feet?
You need to look for the lens throw ratio. That number will tell you how big the size of the image is going to be. Also many projectors have zoom capabilities.
A lens with a 2.0 throw ratio means that for every unit you go away from the projecting surface, the size of the image will grow 2 times (simplest example, you won't find that specific throw distance). So 152"/ 70" gives you a throw ratio of around 2.17.