I had the 3d in my losi 8 before I sold it. Usually ran it on 5s but tried it on 4s a few times. Its going to be really tame on 4s but if you are on a small indoor track it probably would be fine. Kinda like running a 10.5 in a 10th scale 4wd. Not that fast but enough to get over all the jumps and be able to put all the power down.