This might be obvious, but did you turn the steering trim dial to "maximum" on your controller?
Otherwise, I would look in that little magazine that came with the car and do everything that promotes oversteer. Soft springs and tires up front; hard, stiff in rear
A more extreme measure can be found
here
Also, as I understand it, the stock tie rod/steering arm will give the smallest turn radius. Shifting your batteries to the rear-most setting will help as well.